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Chemistry and Chemical Reactivity

John C. Kotz, Paul M. Treichel, John R. Townsend

Chapter 4

Stoichiometry: Quantitative Information About Chemical Reactions - all with Video Answers

Educators

Chapter Questions

02:26

Problem 1

Aluminum reacts with oxygen to give aluminum oxide.
$$
4 \mathrm{Al}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{Al}_{2} \mathrm{O}_{3}(\mathrm{s})
$$
What amount of $\mathrm{O}_{2},$ in moles, is needed for complete reaction with 6.0 mol of Al? What mass of $\mathrm{Al}_{2} \mathrm{O}_{3},$ in grams, can be produced?

Lijeesh Krishnan
Lijeesh Krishnan
Numerade Educator
13:52

Problem 2

What mass of HCl, in grams, is required to react with $0.750 \mathrm{g}$ of $\mathrm{Al}(\mathrm{OH})_{3} ?$ What mass of water, in grams, is produced?
$$\mathrm{Al}(\mathrm{OH})_{3}(\mathrm{s})+3 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{AlCl}_{3}(\mathrm{aq})+3 \mathrm{H}_{2} \mathrm{O}(\ell)$$

Shveta Prithiani
Shveta Prithiani
Numerade Educator
00:58

Problem 3

Like many metals, aluminum reacts with a halogen to give a metal halide (see Figure 2.12 ).
$$
2 \mathrm{Al}(\mathrm{s})+3 \mathrm{Br}_{2}(\ell) \rightarrow \mathrm{Al}_{2} \mathrm{Br}_{6}(\mathrm{s})
$$
What mass of $\mathrm{Br}_{2}$, in grams, is required for complete reaction with $2.56 \mathrm{g}$ of Al? What mass of white, solid $\mathrm{Al}_{2} \mathrm{Br}_{6}$ is expected?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
09:40

Problem 4

The balanced equation for a reaction in the process of the reduction of iron ore to the metal is
$$
\mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{s})+3 \mathrm{CO}(\mathrm{g}) \rightarrow 2 \mathrm{Fe}(\mathrm{s})+3 \mathrm{CO}_{2}(\mathrm{g})
$$
(a) What is the maximum mass of iron, in grams, that can be obtained from $454 \mathrm{g}(1.00 \mathrm{lb})$ of iron(III) oxide?
(b) What mass of $\mathrm{CO}$ is required to react with $454 \mathrm{g}$ of $\mathrm{Fe}_{2} \mathrm{O}_{3} ?$

Shveta Prithiani
Shveta Prithiani
Numerade Educator
18:52

Problem 5

Methane, $\mathrm{CH}_{4},$ burns in oxygen.
(a) What are the products of the reaction?
(b) Write the balanced equation for the reaction.
(c) What mass of $\mathrm{O}_{2}$, in grams, is required for complete combustion of $25.5 \mathrm{g}$ of methane?
(d) What is the total mass of products expected from the combustion of $25.5 \mathrm{g}$ of methane?

Shveta Prithiani
Shveta Prithiani
Numerade Educator
01:20

Problem 6

The formation of water-insoluble silver chloride is useful in the analysis of chloride-containing substances. Consider the following unbalanced equation:
$\mathrm{BaCl}_{2}(\mathrm{aq})+\mathrm{AgNO}_{3}(\mathrm{aq}) \rightarrow \mathrm{AgCl}(\mathrm{s})+\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})$
(a) Write the balanced equation.
(b) What mass of $\mathrm{AgNO}_{3},$ in grams, is required for complete reaction with $0.156 \mathrm{g}$ of $\mathrm{BaCl}_{2} ?$ What mass of AgCl is produced?

David Collins
David Collins
Numerade Educator
01:05

Problem 7

A major source of air pollution years ago was the metals industry. One common process involved "roasting" metal sulfides in the air:
$$
2 \mathrm{PbS}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{PbO}(\mathrm{s})+2 \mathrm{SO}_{2}(\mathrm{g})
$$
If you heat 2.50 mol of $\mathrm{PbS}$ in the air, what amount of $\mathrm{O}_{2}$ is required for complete reaction? What amounts of $\mathrm{PbO}$ and $\mathrm{SO}_{2}$ are expected?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
00:59

Problem 8

Iron ore is converted to iron metal in a reaction with carbon.
$$
2 \mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{s})+3 \mathrm{C}(\mathrm{s}) \rightarrow 4 \mathrm{Fe}(\mathrm{s})+3 \mathrm{CO}_{2}(\mathrm{g})
$$
If 6.2 mol of $\mathrm{Fe}_{2} \mathrm{O}_{3}(\mathrm{s})$ is used, what amount of $\mathrm{C}(\mathrm{s})$ is needed, and what amounts of $\mathrm{Fe}$ and $\mathrm{CO}_{2}$ are produced?

David Collins
David Collins
Numerade Educator
01:19

Problem 9

Chromium metal reacts with oxygen to give chromium(III) oxide, $\mathrm{Cr}_{2} \mathrm{O}_{3}$.
(a) Write a balanced equation for the reaction.
(b) If a piece of chromium has a mass of $0.175 \mathrm{g},$ what mass (in grams) of $\mathrm{Cr}_{2} \mathrm{O}_{3}$ is produced if the metal is converted completely to the oxide?
(c) What mass of $\mathrm{O}_{2}$ (in grams) is required for the reaction?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
01:44

Problem 10

Ethane, $\mathrm{C}_{2} \mathrm{H}_{6},$ burns in oxygen.
(a) What are the products of the reaction?
(b) Write the balanced equation for the reaction.
(c) What mass of $\mathrm{O}_{2}$, in grams, is required for complete combustion of 13.6 of ethane?
(d) What is the total mass of products expected from the combustion of $13.6 \mathrm{g}$ of ethane?

David Collins
David Collins
Numerade Educator
06:12

Problem 11

Sodium sulfide, $\mathrm{Na}_{2} \mathrm{S}$, is used in the leather industry to remove hair from hides. The $\mathrm{Na}_{2} \mathrm{S}$ is made by the reaction
$$\mathrm{Na}_{2} \mathrm{SO}_{4}(\mathrm{s})+4 \mathrm{C}(\mathrm{s}) \rightarrow \mathrm{Na}_{2} \mathrm{S}(\mathrm{s})+4 \mathrm{CO}(\mathrm{g})$$
Suppose you $\operatorname{mix} 15$ g of $\mathrm{Na}_{2} \mathrm{SO}_{4}$ and $7.5 \mathrm{g}$ of $\mathrm{C} .$ Which is the limiting reactant? What mass of $\mathrm{Na}_{2} \mathrm{S}$ is produced?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:56

Problem 12

Ammonia gas can be prepared by the reaction of a metal oxide such as calcium oxide with ammonium chloride.
$$\mathrm{CaO}(\mathrm{s})+2 \mathrm{NH}_{4} \mathrm{Cl}(\mathrm{s}) \rightarrow{2} \mathrm{NH}_{3}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})+\mathrm{CaCl}_{2}(\mathrm{s})$$
If 112 g of $\mathrm{CaO}$ and $224 \mathrm{g}$ of $\mathrm{NH}_{4} \mathrm{Cl}$ are mixed, what is the limiting reactant, and what mass of $\mathrm{NH}_{3}$ can be produced?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
00:47

Problem 13

The compound $\mathrm{SF}_{6}$ is made by burning sulfur in an atmosphere of fluorine. The balanced equation is
$$
\mathrm{S}_{8}(\mathrm{s})+24 \mathrm{F}_{2}(\mathrm{g}) \rightarrow 8 \mathrm{SF}_{6}(\mathrm{g})
$$
If you begin with 1.6 mol of sulfur, $\mathrm{S}_{8},$ and 35 mol of $\mathrm{F}_{2},$ which is the limiting reagent?

David Collins
David Collins
Numerade Educator
05:06

Problem 14

Disulfur dichloride, $\mathrm{S}_{2} \mathrm{Cl}_{2}$ is used to vulcanize rubber. It can be made by treating molten sulfur with gaseous chlorine:
$$\mathrm{S}_{8}(\ell)+4 \mathrm{Cl}_{2}(\mathrm{g}) \rightarrow 4 \mathrm{S}_{2} \mathrm{Cl}_{2}(\ell)$$
Starting with a mixture of $32.0 \mathrm{g}$ of sulfur and $71.0 \mathrm{g}$ of $\mathrm{Cl}_{2}$
(a) Which is the limiting reactant?
(b) What is the theoretical yield of $\mathrm{S}_{2} \mathrm{Cl}_{2} ?$
(c) What mass of the excess reactant remains when the reaction is completed?

Dylan Gunawardene
Dylan Gunawardene
Numerade Educator
00:56

Problem 15

The reaction of methane and water is one way to prepare hydrogen for use as a fuel:
$$
\mathrm{CH}_{4}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightarrow \mathrm{CO}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g})
$$
If you begin with $995 \mathrm{g}$ of $\mathrm{CH}_{4}$ and $2510 \mathrm{g}$ of water,
(a) Which reactant is the limiting reactant?
(b) What is the maximum mass of $\mathrm{H}_{2}$ that can be prepared?
(c) What mass of the excess reactant remains when the reaction is completed?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
05:37

Problem 16

Aluminum chloride, AlCl_, is made by treating scrap aluminum with chlorine.
$$2 \mathrm{Al}(\mathrm{s})+3 \mathrm{Cl}_{2}(\mathrm{g}) \rightarrow 2 \mathrm{AlCl}_{3}(\mathrm{s})$$
If you begin with $2.70 \mathrm{g}$ of $\mathrm{Al}$ and $4.05 \mathrm{g}$ of $\mathrm{Cl}_{2}$,
(a) Which reactant is limiting?
(b) What mass of AlCl $_{3}$ can be produced?
(c) What mass of the excess reactant remains when the reaction is completed?
(d) Set up an amounts table for this problem.

Ronald Prasad
Ronald Prasad
Numerade Educator
02:34

Problem 17

Hexane $\left(\mathrm{C}_{6} \mathrm{H}_{14}\right)$ burns in air $\left(\mathrm{O}_{2}\right)$ to give $\mathrm{CO}_{2}$ and $\mathrm{H}_{2} \mathrm{O}$
(a) Write a balanced equation for the reaction.
If 215 g of $$\mathrm{C}_{6} \mathrm{H}_{14}$$ is mixed with $215 \mathrm{g}$ of $\mathbf{O}_{2}$,what masses of $\mathrm{CO}_{2}$ and $\mathrm{H}_{2} \mathrm{O}$ are produced in the reaction?
(c) What mass of the excess reactant remains after the hexane has been burned?
(d) Set up an amounts table for this problem.

Jacquelin Ho
Jacquelin Ho
Numerade Educator
04:18

Problem 18

Aspirin, $\mathrm{C}_{6} \mathrm{H}_{4}\left(\mathrm{OCOCH}_{3}\right) \mathrm{CO}_{2} \mathrm{H}$, is produced by the reaction of salicylic acid, $\mathrm{C}_{6} \mathrm{H}_{4}(\mathrm{OH}) \mathrm{CO}_{2} \mathrm{H}$, and acetic anhydride, $\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}($ page 168$)$.
$$\begin{array}{r}
\mathrm{C}_{6} \mathrm{H}_{4}(\mathrm{OH}) \mathrm{CO}_{2} \mathrm{H}(\mathrm{s})+\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}(\ell) \rightarrow \\
\mathrm{C}_{6} \mathrm{H}_{4}\left(\mathrm{OCOCH}_{3}\right) \mathrm{CO}_{2} \mathrm{H}(\mathrm{s})+\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}(\ell)
\end{array}$$
If you mix $100 . \mathrm{g}$ of each of the reactants, what is the maximum mass of aspirin that can be obtained?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
01:43

Problem 19

In Example $4.2,$ you found that a particular mixture of $\mathrm{CO}$ and $\mathrm{H}_{2}$ could produce $407 \mathrm{g}$ $$\mathrm{CH}_{3} \mathrm{OH}$$
$$\mathrm{CO}(\mathrm{g})+2 \mathrm{H}_{2}(\mathrm{g}) \rightarrow \mathrm{CH}_{3} \mathrm{OH}(\ell)$$
If only $332 \mathrm{g}$ of $\mathrm{CH}_{3} \mathrm{OH}$ is actually produced, what is the percent yield of the compound?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
00:58

Problem 20

Ammonia gas can be prepared by the following reaction:
$$\begin{aligned}
\mathrm{CaO}(\mathrm{s})+2 \mathrm{NH}_{4} \mathrm{Cl}(\mathrm{s}) & \rightarrow \\
& 2 \mathrm{NH}_{3}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})+\mathrm{CaCl}_{2}(\mathrm{s})
\end{aligned}$$
If $112 \mathrm{g}$ of $\mathrm{CaO}$ and $224 \mathrm{g}$ of $\mathrm{NH}_{4} \mathrm{Cl}$ are mixed, the theoretical yield of $\mathrm{NH}_{3}$ is $68.0 \mathrm{g}$ (Study Question 12 ). If only $16.3 \mathrm{g}$ of $\mathrm{NH}_{3}$ is actually obtained, what is its percent yield?

Ronald Prasad
Ronald Prasad
Numerade Educator
00:46

Problem 21

The deep blue compound $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{SO}_{4}$ is made by the reaction of copper(II) sulfate and ammonia.
$$
\mathrm{CuSO}_{4}(\mathrm{aq})+4 \mathrm{NH}_{3}(\mathrm{aq}) \rightarrow \mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{SO}_{4}(\mathrm{aq})
$$
(a) If you use $10.0 \mathrm{g}$ of $\mathrm{CuSO}_{4}$ and excess $\mathrm{NH}_{3},$ what is the theoretical yield of $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{SO}_{4} ?$
(b) If you isolate $12.6 \mathrm{g}$ of $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{SO}_{4},$ what is the percent yield of $\mathrm{Cu}\left(\mathrm{NH}_{3}\right)_{4} \mathrm{SO}_{4} ?$

Jacquelin Ho
Jacquelin Ho
Numerade Educator
03:17

Problem 22

Black smokers are found in the depths of the oceans (page 112 ). Thinking that the conditions in these smokers might be conducive to the formation of organic compounds, two chemists in Germany found the following reaction could occur in similar conditions.
$$2 \mathrm{CH}_{3} \mathrm{SH}+\mathrm{CO} \rightarrow \mathrm{CH}_{3} \mathrm{COSCH}_{3}+\mathrm{H}_{2} \mathrm{S}$$
If you begin with $10.0 \mathrm{g}$ of $\mathrm{CH}_{3} \mathrm{SH}$ and excess $\mathrm{CO}$
(a) What is the theoretical yield of $\mathrm{CH}_{3} \mathrm{COSCH}_{3} ?$
(b) If $8.65 \mathrm{g}$ of $\mathrm{CH}_{3} \mathrm{COSCH}_{3}$ is isolated, what is its percent yield?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
05:58

Problem 23

A mixture of $$\mathrm{CuSO}_{4} \text { and } \mathrm{CuSO}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O}$$ has a mass of 1.245 g. After heating to drive off all the water, the mass is only $0.832 \mathrm{g} .$ What is the mass percent of $$\mathrm{CuSO}_{4} \cdot 5 \mathrm{H}_{2} \mathrm{O}$$ in the mixture? (See page $97 .)$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:52

Problem 24

A $2.634-\mathrm{g}$ sample containing impure $\mathrm{CuCl}_{2} \cdot 2 \mathrm{H}_{2} \mathrm{O}$
was heated. The sample mass after heating to drive off the water was $2.125 \mathrm{g} .$ What was the mass percent of $\mathrm{CuCl}_{2} \cdot 2 \mathrm{H}_{2} \mathrm{O}$ in the original sample?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:59

Problem 25

A sample of limestone and other soil materials was heated, and the limestone decomposed to give calcium oxide and carbon dioxide.
$$
\mathrm{CaCO}_{3}(\mathrm{s}) \rightarrow \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})
$$
A $1.506-\mathrm{g}$ sample of limestone-containing material gave $0.558 \mathrm{g}$ of $\mathrm{CO}_{2},$ in addition to $\mathrm{CaO},$ after being heated at a high temperature. What is the mass percent of $\mathrm{CaCO}_{3}$ in the original sample?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:38

Problem 26

At higher temperatures, NaHCO is converted quantitatively to $\mathrm{Na}_{2} \mathrm{CO}_{3}$
$$
2 \mathrm{NaHCO}_{3}(\mathrm{s}) \rightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\mathrm{g})
$$
Heating a 1.7184 -g sample of impure $\mathrm{NaHCO}_{3}$ gives $0.196 \mathrm{g}$ of $\mathrm{CO}_{2} .$ What was the mass percent of $\mathrm{NaHCO}_{3}$ in the original $1.7184-\mathrm{g}$ sample?

Ronald Prasad
Ronald Prasad
Numerade Educator
00:54

Problem 27

A pesticide contains thallium (I) sulfate, $\mathrm{Tl}_{2} \mathrm{SO}_{4}$. Dissolving a $10.20-\mathrm{g}$ sample of impure pesticide in water and adding sodium iodide precipitates $0.1964 \mathrm{g}$ of thallium(I) iodide, TII.
$\mathrm{TI}_{2} \mathrm{SO}_{4}(\mathrm{aq})+2 \mathrm{NaI}(\mathrm{aq}) \rightarrow 2 \mathrm{TII}(\mathrm{s})+\mathrm{Na}_{2} \mathrm{SO}_{4}(\mathrm{aq})$
What is the mass percent of $\mathrm{Tl}_{2} \mathrm{SO}_{4}$ in the original $10.20-\mathrm{g}$ sample?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
00:45

Problem 28

The aluminum in a 0.764 -g sample of an unknown material was precipitated as aluminum hydroxide, $\mathrm{Al}(\mathrm{OH})_{3},$ which was then converted to $\mathrm{Al}_{2} \mathrm{O}_{3}$ by heating strongly. If $0.127 \mathrm{g}$ of $\mathrm{Al}_{2} \mathrm{O}_{3}$ is obtained from the 0.764 g sample, what is the mass percent of aluminum in the sample?

David Collins
David Collins
Numerade Educator
00:48

Problem 29

Styrene, the building block of polystyrene, consists of only $\mathrm{C}$ and $\mathrm{H}$. If $0.438 \mathrm{g}$ of styrene is burned in oxygen and produces $1.481 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.303 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O},$ what is the empirical formula of styrene?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
01:18

Problem 30

Mesitylene is a liquid hydrocarbon. Burning 0.115 g of the compound in oxygen gives $0.379 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.1035 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O} .$ What is the empirical formula of mesitylene?

David Collins
David Collins
Numerade Educator
01:01

Problem 31

Cyclopentane is a simple hydrocarbon. If $0.0956 \mathrm{g}$ of the compound is burned in oxygen, $0.300 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.123 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O}$ are isolated.
(a) What is the empirical formula of cyclopentane?
(b) If a separate experiment gave $70.1 \mathrm{g} / \mathrm{mol}$ as the molar mass of the compound, what is its molecular formula?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
01:00

Problem 32

Azulene is a beautiful blue hydrocarbon. If $0.106 \mathrm{g}$ of the compound is burned in oxygen, $0.364 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.0596 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O}$ are isolated.
(a) What is the empirical formula of azulene?
(b) If a separate experiment gave $128.2 \mathrm{g} / \mathrm{mol}$ as the molar mass of the compound, what is its molecular formula?

David Collins
David Collins
Numerade Educator
01:21

Problem 33

An unknown compound has the formula $\mathrm{C}_{x} \mathrm{H}_{y} \mathrm{O}_{z} .$ You burn 0.0956 g of the compound and isolate $0.1356 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.0833 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O} .$ What is the empirical formula of the compound? If the molar mass is $62.1 \mathrm{g} /$ mol, what is the molecular formula? (See Exercise 4.6.)

Jacquelin Ho
Jacquelin Ho
Numerade Educator
05:46

Problem 34

An unknown compound has the formula $\mathrm{C}_{x} \mathrm{H}, \mathrm{O}_{z}$ You burn $0.1523 \mathrm{g}$ of the compound and isolate $0.3718 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.1522 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O} .$ What is the empirical formula of the compound? If the molar mass is $72.1 \mathrm{g} / \mathrm{mol},$ what is the molecular formula? (See Exercise $4.6 .)$

Ronald Prasad
Ronald Prasad
Numerade Educator
07:30

Problem 35

Nickel forms a compound with carbon monoxide, $\mathrm{Ni}_{x}(\mathrm{CO}),$ To determine its formula, you carefully heat a 0.0973 -g sample in air to convert the nickel to 0.0426 g of $\mathrm{NiO}$ and the $\mathrm{CO}$ to $0.100 \mathrm{g}$ of $\mathrm{CO}_{2} .$ What is the empirical formula of $\mathrm{Ni}_{x}(\mathrm{CO})_{y} ?$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:35

Problem 36

To find the formula of a compound composed of iron and carbon monoxide, $\mathrm{Fe}_{x}(\mathrm{CO})_{y},$ the compound is burned in pure oxygen to give $\mathrm{Fe}_{2} \mathrm{O}_{3}$ and $\mathrm{CO}_{2}$. If you burn $1.959 \mathrm{g}$ of $\mathrm{Fe}_{x}(\mathrm{CO})_{y}$ and obtain $0.799 \mathrm{g}$ of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ and $2.200 \mathrm{g}$ of $\mathrm{CO}_{2},$ what is the empirical formula of $\mathrm{Fe}_{x}(\mathrm{CO})_{y} ?$

Hailey Tomashek
Hailey Tomashek
Numerade Educator
04:53

Problem 37

If $6.73 \mathrm{g}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ is dissolved in enough water to make $250 .$ mL of solution, what is the molar concentration of the sodium carbonate? What are the molar concentrations of the $\mathrm{Na}^{+}$ and $\mathrm{CO}_{3}^{2-}$ ions?

Angelina Chavez
Angelina Chavez
Numerade Educator
01:56

Problem 38

Some potassium dichromate $\left(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\right), 2.335 \mathrm{g},$ is dissolved in enough water to make exactly $500 .$ mL of solution. What is the molar concentration of the potassium dichromate? What are the molar concentrations of the $\mathrm{K}^{+}$ and $\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$ ions?

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
02:37

Problem 39

What is the mass of solute, in grams, in $250 .$ mL of a $0.0125 \mathrm{M}$ solution of $\mathrm{KMnO}_{4}$ ?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:37

Problem 40

What is the mass of solute, in grams, in 125 mL of a $1.023 \times 10^{-3} \mathrm{M}$ solution of $\mathrm{Na}_{3} \mathrm{PO}_{4} ?$ What is the molar concentration of the $\mathrm{Na}^{+}$ and $\mathrm{PO}_{4}{^3}{^-}$ ion?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:10

Problem 41

What volume of $0.123 \mathrm{M} \mathrm{NaOH},$ in milliliters, contains $25.0 \mathrm{g}$ of $\mathrm{NaOH} ?$

Angelina Chavez
Angelina Chavez
Numerade Educator
02:10

Problem 42

What volume of $2.06 \mathrm{M} \mathrm{KMnO}_{4},$ in liters, contains 322 g of solute?

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
04:12

Problem 43

For each solution, identify the ions that exist in aqueous solution, and specify the concentration of each ion.
(a) $0.25 \mathrm{M}\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$
(b) $0.123 \mathrm{M} \mathrm{Na}_{2} \mathrm{CO}_{3}$
(c) $0.056 \mathrm{M} \mathrm{HNO}_{3}$

Angelina Chavez
Angelina Chavez
Numerade Educator
02:35

Problem 44

For each solution, identify the ions that exist in aqueous solution, and specify the concentration of each ion.
(a) $0.12 \mathrm{M} \mathrm{BaCl}_{2}$
(b) $0.0125 \mathrm{M} \mathrm{CuSO}_{4}$
(c) $0.500 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
04:54

Problem 45

An experiment in your laboratory requires $500 .$ mL of a $0.0200 \mathrm{M}$ solution of $\mathrm{Na}_{2} \mathrm{CO}_{3} .$ You are given solid $\mathrm{Na}_{2} \mathrm{CO}_{3},$ distilled water, and a $500 .$ -mL volumetric flask. Describe how to prepare the required solution.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:23

Problem 46

What mass of oxalic acid, $\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4},$ is required to prepare $250 .$ mL of a solution that has a concentration of $0.15 \mathrm{M} \mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:13

Problem 47

If you dilute $25.0 \mathrm{mL}$ of $1.50 \mathrm{M}$ hydrochloric acid to $500 . \mathrm{mL},$ what is the molar concentration of the dilute acid?

Angelina Chavez
Angelina Chavez
Numerade Educator
01:23

Problem 48

If $4.00 \mathrm{mL}$ of $0.0250 \mathrm{M} \mathrm{CuSO}_{4}$ is diluted to $10.0 \mathrm{mL}$
with pure water, what is the molar concentration of copper(II) sulfate in the diluted solution?

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
02:30

Problem 49

Which of the following methods would you use to prepare $1.00 \mathrm{L}$ of $0.125 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4} ?$
(a) Dilute $20.8 \mathrm{mL}$ of $6.00 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}$ to a volume of
$1.00 \mathrm{L}$
(b) Add $950 .$ mL of water to 50.0 mL of $3.00 \mathrm{M} \mathrm{H}_{2} \mathrm{SO}_{4}$

Angelina Chavez
Angelina Chavez
Numerade Educator
01:55

Problem 50

Which of the following methods would you use to prepare $300 .$ mL of $0.500 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7} ?$
(a) Add $30.0 \mathrm{mL}$ of $1.50 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ to $270 .$ mL of water.
(b) Dilute $250 .$ mL of $0.600 \mathrm{M} \mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ to a volume of
$300 . \mathrm{mL}$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
02:55

Problem 51

You have $250 .$ mL of $0.136 \mathrm{M}$ HCl. Using a volumetric pipet, you take $25.00 \mathrm{mL}$ of that solution and dilute it to $100.00 \mathrm{mL}$ in a volumetric flask. Now you take $10.00 \mathrm{mL}$ of that solution, using a volumetric pipet, and dilute it to $100.00 \mathrm{mL}$ in a volumetric flask. What is the concentration of hydrochloric acid in the final solution?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:04

Problem 52

Suppose you have $100.00 \mathrm{mL}$ a solution of a dye and transfer $2.00 \mathrm{mL}$ of the solution to a $100.00-\mathrm{mL}$ volumetric flask. After adding water to the $100.00 \mathrm{mL}$ mark, you take 5.00 mL of that solution and again dilute to $100.00 \mathrm{mL}$. If you find the dye concentration in the final diluted sample is $0.000158 \mathrm{M},$ what was the dye concentration in the original solution?

Anna D.
Anna D.
Numerade Educator
01:24

Problem 53

A table wine has a pH of $3.40 .$ What is the hydronium ion concentration of the wine? Is it acidic or basic?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
04:01

Problem 54

A saturated solution of milk of magnesia, $\mathrm{Mg}(\mathrm{OH})_{2}$ has a pH of $10.5 .$ What is the hydronium ion concentration of the solution? Is the solution acidic or basic?

Vishal Sharma
Vishal Sharma
Numerade Educator
01:21

Problem 55

What is the hydronium ion concentration of a 0.0013 M solution of HNOs? What is its pH?

Angelina Chavez
Angelina Chavez
Numerade Educator
00:53

Problem 56

What is the hydronium ion concentration of a $1.2 \times 10^{-4} \mathrm{M}$ solution of $\mathrm{HClO}_{4} ?$ What is its $\mathrm{pH} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:44

Problem 57

Make the following conversions. In each case, tell whether the solution is acidic or basic.
$$\begin{array}{ll}
\text { pH } & {\left[\mathrm{H}_{3} \mathrm{O}^{+}\right]} \\
\text { (a) } 1.00 & \underline{\quad \quad}\\
\text { (b) } 10.50 &\underline{\quad \quad}\\
\text { (c) } \underline{\quad \quad}& {1.3 \times} 10^{-5} \mathrm{M} \\
\text { (d) } \underline{\quad \quad}& 2.3 \times 10^{-8} \mathrm{M}
\end{array}$$

HC
Harliv Chakkal
Numerade Educator
02:49

Problem 58

Make the following conversions. In each case, tell whether the solution is acidic or basic.
(TABLE CANNOT COPY)

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:54

Problem 59

What volume of $0.109 \mathrm{M} \mathrm{HNO}_{3},$ in milliliters, is required to react completely with $2.50 \mathrm{g}$ of $\mathrm{Ba}(\mathrm{OH})_{2} ?$ $2 \mathrm{HNO}_{3}(\mathrm{aq})+\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{s}) \rightarrow$
$$
2 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})
$$

Angelina Chavez
Angelina Chavez
Numerade Educator
03:20

Problem 60

What mass of $\mathrm{Na}_{2} \mathrm{CO}_{3},$ in grams, is required for complete reaction with $50.0 \mathrm{mL}$ of $0.125 \mathrm{M} \mathrm{HNO}_{3} ?$
$\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+2 \mathrm{HNO}_{3}(\mathrm{aq}) \rightarrow$
$$
2 \mathrm{NaNO}_{3}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell)
$$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
03:32

Problem 61

When an electric current is passed through an aqueous solution of $\mathrm{NaCl}$, the valuable industrial chemicals $\mathrm{H}_{2}(\mathrm{g}), \mathrm{Cl}_{2}(\mathrm{g}),$ and $\mathrm{NaOH}$ are produced.
$2 \mathrm{NaCl}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow$
$$
\mathrm{H}_{2}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g})+2 \mathrm{NaOH}(\mathrm{aq})
$$
What mass of NaOH can be formed from $15.0 \mathrm{L}$ of $0.35 \mathrm{M} \mathrm{NaCl} ?$ What mass of chlorine is obtained?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
03:15

Problem 62

Hydrazine, $\mathrm{N}_{2} \mathrm{H}_{4},$ a base-like ammonia, can react with sulfuric acid.
$$
2 \mathrm{N}_{2} \mathrm{H}_{4}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) \rightarrow 2 \mathrm{N}_{2} \mathrm{H}_{5}^{+}(\mathrm{aq})+\mathrm{SO}_{4}^{2-}(\mathrm{aq})
$$
What mass of hydrazine reacts with $250 .$ mL of $0.146 \mathrm{M}$ $\mathrm{H}_{2} \mathrm{SO}_{4} ?$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
04:04

Problem 63

In the photographic developing process, silver bromide is dissolved by adding sodium thiosulfate.
$\mathrm{AgBr}(\mathrm{s})+2 \mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3}(\mathrm{aq}) \rightarrow$
$$
\mathrm{Na}_{3} \mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{2}(\mathrm{aq})+\mathrm{NaBr}(\mathrm{aq})
$$
If you want to dissolve $0.225 \mathrm{g}$ of $\mathrm{AgBr}$, what volume of $0.0138 \mathrm{M} \mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3},$ in milliliters, should be used?
(IMAGE CANNOT COPY)

Susan Hallstrom
Susan Hallstrom
Numerade Educator
04:38

Problem 64

You can dissolve an aluminum soft-drink can in an aqueous base such as potassium hydroxide.
$2 \mathrm{Al}(\mathrm{s})+2 \mathrm{KOH}(\mathrm{aq})+6 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow$
$$
2 \mathrm{KAl}(\mathrm{OH})_{4}(\mathrm{aq})+3 \mathrm{H}_{2}(\mathrm{g})
$$
If you place $2.05 \mathrm{g}$ of aluminum in a beaker with 185 mL of $1.35 \mathrm{M} \mathrm{KOH},$ will any aluminum remain? What mass of $\mathrm{KAl}(\mathrm{OH})_{4}$ is produced?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:37

Problem 65

What volume of $0.750 \mathrm{M} \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2},$ in milliliters, is required to react completely with $1.00 \mathrm{L}$ of $2.25 \mathrm{M} \mathrm{NaCl}$ solution? The balanced equation is
$\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+2 \mathrm{NaCl}(\mathrm{aq}) \rightarrow$
$$
\mathrm{PbCl}_{2}(\mathrm{s})+2 \mathrm{NaNO}_{3}(\mathrm{aq})
$$

Angelina Chavez
Angelina Chavez
Numerade Educator
04:05

Problem 66

What volume of 0.125 M oxalic acid, $\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$ is required to react with $35.2 \mathrm{mL}$ of $0.546 \mathrm{M} \mathrm{NaOH} ?$
$\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow$
$$
\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell)
$$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
02:25

Problem 67

What volume of $0.812 \mathrm{M} \mathrm{HCl}$, in milliliters, is required to titrate $1.45 \mathrm{g}$ of $\mathrm{NaOH}$ to the equivalence point?
$$\mathrm{NaOH}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{NaCl}(\mathrm{aq})$$

Angelina Chavez
Angelina Chavez
Numerade Educator
03:09

Problem 68

What volume of $0.955 \mathrm{M} \mathrm{HCl},$ in milliliters, is required to titrate $2.152 \mathrm{g}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ to the equivalence point?
$\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow$
$$
\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})+2 \mathrm{NaCl}(\mathrm{aq})
$$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
04:11

Problem 69

If 38.55 mL of $\mathrm{HCl}$ is required to titrate $2.150 \mathrm{g}$ of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ according to the following equation, what is the concentration $(\mathrm{mol} / \mathrm{L})$ of the HCl solution?
$\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow$
$$
2 \mathrm{NaCl}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell)
$$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:42

Problem 70

Potassium hydrogen phthalate, $\mathrm{KHC}_{8} \mathrm{H}_{4} \mathrm{O}_{4},$ is used to standardize solutions of bases. The acidic anion reacts with strong bases according to the following net ionic equation:
$\mathrm{HC}_{8} \mathrm{H}_{4} \mathrm{O}_{4}^{-}(\mathrm{aq})+\mathrm{OH}^{-}(\mathrm{aq}) \rightarrow$
$$
\mathrm{C}_{8} \mathrm{H}_{4} \mathrm{O}_{4}^{2-}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)
$$
If a 0.902 -g sample of potassium hydrogen phthalate is dissolved in water and titrated to the equivalence point with $26.45 \mathrm{mL}$ of $\mathrm{NaOH},$ what is the molar concentration of the NaOH?

Michelle Neer
Michelle Neer
Numerade Educator
04:41

Problem 71

You have $0.954 \mathrm{g}$ of an unknown acid, $\mathrm{H}_{2} \mathrm{A},$ which reacts with NaOH according to the balanced equation
$$\mathrm{H}_{2} \mathrm{A}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow \mathrm{Na}_{2} \mathrm{A}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell)$$
If $36.04 \mathrm{mL}$ of $0.509 \mathrm{M} \mathrm{NaOH}$ is required to titrate the acid to the second equivalence point, what is the molar mass of the acid?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:39

Problem 72

An unknown solid acid is either citric acid or tartaric acid. To determine which acid you have, you titrate a sample of the solid with aqueous $\mathrm{NaOH}$ and from this determine the molar mass of the unknown acid. The appropriate equations are as follows:
Citric acid:
$\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{NaOH}(\mathrm{aq}) \rightarrow$
$$
3 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})
$$
Tartanic acid:
$\mathrm{H}_{2} \mathrm{C}_{4} \mathrm{H}_{4} \mathrm{O}_{6}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow$
$$
2 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Na}_{2} \mathrm{C}_{4} \mathrm{H}_{4} \mathrm{O}_{6}(\mathrm{aq})
$$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:26

Problem 73

To analyze an iron-containing compound, you convert all the iron to $\mathrm{Fe}^{2+}$ in aqueous solution and then titrate the solution with standardized $\mathrm{KMnO}_{4} .$ The balanced, net ionic equation is
$$\begin{aligned}
\mathrm{MnO}_{4}^{-}(\mathrm{aq})+5 \mathrm{Fe}^{2+}(\mathrm{aq})+8 \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq}) & \rightarrow \\
& \mathrm{Mn}^{2+}(\mathrm{aq})+5 \mathrm{Fe}^{3+}(\mathrm{aq})+12 \mathrm{H}_{2} \mathrm{O}(\ell)
\end{aligned}$$
A $0.598-\mathrm{g}$ sample of the iron-containing compound requires $22.25 \mathrm{mL}$ of $0.0123 \mathrm{M} \mathrm{KMnO}_{4}$ for titration to the equivalence point. What is the mass percent of iron in the sample?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:21

Problem 74

Vitamin C has the formula $\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6} .$ Besides being an acid, it is a reducing agent. One method for determining the amount of vitamin $\mathrm{C}$ in a sample is therefore to titrate it with a solution of bromine, $\mathrm{Br}_{2},$ an oxidizing agent.
$$\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}(\mathrm{aq})+\mathrm{Br}_{2}(\mathrm{aq}) \rightarrow 2 \mathrm{HBr}(\mathrm{aq})+\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{6}(\mathrm{aq})$$
A $1.00-\mathrm{g}$ "chewable" vitamin C tablet requires $27.85 \mathrm{mL}$ of $0.102 \mathrm{M} \mathrm{Br}_{2}$ for titration to the equivalence point. What is the mass of vitamin $\mathrm{C}$ in the tablet?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:13

Problem 75

A solution of a dye was analyzed by spectrophotometry, and the following calibration data were collected.
(TABLE CANNOT COPY)
(a) Construct a calibration plot, and determine the slope and intercept.
(b) What is the dye concentration in a solution with $A=0.52 ?$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:21

Problem 76

The nitrite ion is involved in the biochemical nitrogen cycle. You can analyze for the nitrite ion content of a sample using spectrophotometry by first using several organic compounds to create a colored compound from the ion. The following data were collected.
(TABLE CANNOT COPY)
(a) Construct a calibration plot, and determine the slope and intercept.
(b) What is the nitrite ion concentration in the unknown solution?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:22

Problem 77

Suppose $16.04 \mathrm{g}$ of benzene, $\mathrm{C}_{6} \mathrm{H}_{6},$ is burned in oxygen.
(a) What are the products of the reaction?
(b) What is the balanced equation for the reaction?
(c) What mass of $\mathrm{O}_{2}$, in grams, is required for complete combustion of benzene?
(d) What is the total mass of products expected from $16.04 \mathrm{g}$ of benzene?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
03:38

Problem 78

The metabolic disorder diabetes causes a buildup of acetone, $\mathrm{CH}_{3} \mathrm{COCH}_{3},$ in the blood. Acetone, a volatile compound, is exhaled, giving the breath of untreated diabetics a distinctive odor. The acetone is produced by a breakdown of fats in a series of reactions. The equation for the last step, the breakdown of acetoacetic acid to give acetone and $\mathrm{CO}_{2}$, is
$$\mathrm{CH}_{3} \mathrm{COCH}_{2} \mathrm{CO}_{2} \mathrm{H} \rightarrow \mathrm{CH}_{3} \mathrm{COCH}_{3}+\mathrm{CO}_{2}$$
(FIGURE CANNOT COPY)
What mass of acetone can be produced from $125 \mathrm{mg}$ of acetoacetic acid?

Ronald Prasad
Ronald Prasad
Numerade Educator
05:54

Problem 79

Your body deals with excess nitrogen by excreting it in the form of urea, $\mathrm{NH}_{2} \mathrm{CONH}_{2}$. The reaction producing it is the combination of arginine $\left(\mathrm{C}_{6} \mathrm{H}_{14} \mathrm{N}_{4} \mathrm{O}_{2}\right)$ with water to give urea and ornithine $\left(\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{N}_{2} \mathrm{O}_{2}\right)$
$$
\mathrm{C}_{6} \mathrm{H}_{14} \mathrm{N}_{4} \mathrm{O}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{NH}_{2} \mathrm{CONH}_{2}+\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{N}_{2} \mathrm{O}_{2}
$$
Arginine Urea Ornithine
If you excrete 95 mg of urea, what mass of arginine must have been used? What mass of ornithine must have been produced?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
05:05

Problem 80

The reaction of iron metal and chlorine gas to give iron(III) chloride is illustrated in Figure 3.2
(a) Write the balanced chemical equation for the reaction.
(b) Beginning with $10.0 \mathrm{g}$ of iron, what mass of $\mathrm{Cl}_{2},$ in grams, is required for complete reaction? What mass of $\mathrm{FeCl}_{3}$ can be produced?
(c) If only $18.5 \mathrm{g}$ of $\mathrm{FeCl}_{3}$ is obtained from $10.0 \mathrm{g}$ of iron and excess $\mathrm{Cl}_{2},$ what is the percent yield?
(d) If $10.0 \mathrm{g}$ each of iron and chlorine are combined, what is the theoretical yield of iron(III) chloride?

Ronald Prasad
Ronald Prasad
Numerade Educator
08:25

Problem 81

Some metal halides react with water to produce the metal oxide and the appropriate hydrogen halide (see photo). For example,
$$
\mathrm{TiCl}_{4}(\ell)+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow \mathrm{TiO}_{2}(\mathrm{s})+4 \mathrm{HCl}(\mathrm{g})
$$
(FIGURE CANNOT COPY)
(a) Name the four compounds involved in this reaction.
(b) If you begin with $14.0 \mathrm{mL}$ of $\mathrm{TiCl}_{4}(d=1.73 \mathrm{g} / \mathrm{mL})$
what mass of water, in grams, is required for complete reaction?
(c) What mass of each product is expected?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:19

Problem 82

The reaction of $750 .$ g each of $\mathrm{NH}_{3}$ and $\mathrm{O}_{2}$ was found to produce $562 \mathrm{g}$ of $\mathrm{NO}$ (see pages $163-165$ ).
$$
4 \mathrm{NH}_{3}(\mathrm{g})+5 \mathrm{O}_{2}(\mathrm{g}) \rightarrow 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_{2} \mathrm{O}(\ell)
$$
(a) What mass of water is produced by this reaction?
(b) What mass of $\mathrm{O}_{2}$ is required to consume $750 .$ g of $\mathrm{NH}_{3} ?$

Ronald Prasad
Ronald Prasad
Numerade Educator
02:58

Problem 83

Sodium azide, the explosive chemical used in automobile airbags, is made by the following reaction:
$$
\mathrm{NaNO}_{3}+3 \mathrm{NaNH}_{2} \rightarrow \mathrm{NaN}_{3}+3 \mathrm{NaOH}+\mathrm{NH}_{3}
$$
If you combine $15.0 \mathrm{g}$ of $\mathrm{NaNO}_{3}(85.0 \mathrm{g} / \mathrm{mol})$ with
$15.0 \mathrm{g}$ of $\mathrm{NaNH}_{2},$ what mass of $\mathrm{NaN}_{3}$ is produced?

Jacquelin Ho
Jacquelin Ho
Numerade Educator
07:34

Problem 84

Iodine is made by the following reaction
$2 \mathrm{NaIO}_{3}(\mathrm{aq})+5 \mathrm{NaHSO}_{3}(\mathrm{aq}) \rightarrow$
$$
3 \mathrm{NaHSO}_{4}(\mathrm{aq})+2 \mathrm{Na}_{2} \mathrm{SO}_{4}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{I}_{2}(\mathrm{aq})
$$
(a) Name the two reactants.
(b) If you wish to prepare $1.00 \mathrm{kg}$ of $\mathrm{I}_{2},$ what mass of $\mathrm{NaIO}_{3}$ is required? What mass of $\mathrm{NaHSO}_{3} ?$
(c) What is the theoretical yield of $I_{2}$ if you mixed $15.0 \mathrm{g}$ of $\mathrm{NaIO}_{3}$ with $125 \mathrm{mL}$ of $0.853 \mathrm{M} \mathrm{NaHSO}_{3} ?$

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
00:43

Problem 85

Saccharin, an artificial sweetener, has the formula $\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{NO}_{3} \mathrm{S} .$ Suppose you have a sample of a saccharincontaining sweetener with a mass of $0.2140 \mathrm{g} .$ After decomposition to free the sulfur and convert it to the $\mathrm{SO}_{4}{^2}{^-}$ ion, the sulfate ion is trapped as water-insoluble BaSO (see Figure 4.6 ). The quantity of $\mathrm{BaSO}_{4}$ obtained is $0.2070 \mathrm{g} .$ What is the mass percent of saccharin in the sample of sweetener?

David Collins
David Collins
Numerade Educator
01:39

Problem 86

Boron forms an extensive series of compounds with hydrogen, all with the general formula $\mathbf{B}_{x} \mathbf{H}_{y}$
$$\mathrm{B}_{x} \mathrm{H}_{y}(\mathrm{s})+\operatorname{excess} \mathrm{O}_{2}(\mathrm{g}) \rightarrow \frac{x}{2} \mathrm{B}_{2} \mathrm{O}_{3}(\mathrm{s})+\frac{y}{2} \mathrm{H}_{2} \mathrm{O}(\mathrm{g})$$
If $0.148 \mathrm{g}$ of $\mathrm{B}_{x} \mathrm{H}_{y}$ gives $0.422 \mathrm{g}$ of $\mathrm{B}_{2} \mathrm{O}_{3}$ when burned in excess $\mathrm{O}_{2},$ what is the empirical formula of $\mathrm{B}_{x} \mathrm{H}_{y} ?$

David Collins
David Collins
Numerade Educator
01:03

Problem 87

Silicon and hydrogen form a series of compounds with the general formula $\mathrm{Si}_{x} \mathrm{H}_{y}$. To find the formula of one of them, a 6.22 -g sample of the compound is burned in oxygen. All of the Si is converted to $11.64 \mathrm{g}$ of $\mathrm{Si} \mathrm{O}_{2}$ and all of the $\mathrm{H}$ is converted to $6.980 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O} .$ What is the empirical formula of the silicon compound?

David Collins
David Collins
Numerade Educator
02:20

Problem 88

Menthol, from oil of mint, has a characteristic odor. The compound contains only $\mathrm{C}, \mathrm{H},$ and $\mathrm{O} .$ If $95.6 \mathrm{mg}$ of menthol burns completely in $\mathrm{O}_{2},$ and gives $269 \mathrm{mg}$ of $\mathrm{CO}_{2}$ and $110 \mathrm{mg}$ of $\mathrm{H}_{2} \mathrm{O},$ what is the empirical formula of menthol?

David Collins
David Collins
Numerade Educator
02:01

Problem 89

Quinone, a chemical used in the dye industry and in photography, is an organic compound containing only C, H, and O. What is the empirical formula of the compound if $0.105 \mathrm{g}$ of the compound gives $0.257 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $0.0350 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O}$ when burned completely in oxygen?

David Collins
David Collins
Numerade Educator
06:20

Problem 90

Iron (II) chloride and sodium sulfide react to form iron(II)sulfide and sodium chloride (ChemistryNow Screen $4.8 .$
(a) Write the balanced equation for the reaction.
(b) If you combine 40 g each of $\mathrm{Na}_{2} \mathrm{S}$ and $\mathrm{FeCl}_{2}$, what is the limiting reactant?
(c) What mass of FeS is produced?
(d) What mass of $\mathrm{Na}_{2} \mathrm{S}$ or $\mathrm{FeCl}_{2}$ remains after the reaction?
(e) What mass of $\mathrm{FeCl}_{2}$ is required to react completely with $40 \mathrm{g}$ of $\mathrm{Na}_{2} \mathrm{S}$ ?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:09

Problem 91

Sulfuric acid can be prepared starting with the sulfide ore, cuprite $\left(\mathrm{Cu}_{2} \mathrm{S}\right) .$ If each $\mathrm{S}$ atom in $\mathrm{Cu}_{2} \mathrm{S}$ leads to one molecule of $\mathrm{H}_{2} \mathrm{SO}_{4},$ what is the theoretical yield of $\mathrm{H}_{2} \mathrm{SO}_{4}$ from $3.00 \mathrm{kg}$ of $\mathrm{Cu}_{2} \mathrm{S} ?$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:31

Problem 92

In an experiment, $1.056 \mathrm{g}$ of a metal carbonate, containing an unknown metal $\mathrm{M}$, is heated to give the metal oxide and $0.376 \mathrm{g} \mathrm{CO}_{2}$
$$\mathrm{MCO}_{3}(\mathrm{s})+\text { heat } \rightarrow \mathrm{MO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})$$
What is the identity of the metal M?
(a) $\mathrm{M}=\mathrm{Ni}$
(b) $\mathrm{M}=\mathrm{Cu}$
(c) $\mathrm{M}=\mathrm{Zn}$
(d) $\mathbf{M}=\mathbf{B a}$

David Collins
David Collins
Numerade Educator
01:46

Problem 93

An unknown metal reacts with oxygen to give the metal oxide, MO $_{2}$. Identify the metal based on the following information:
Mass of metal $=0.356 \mathrm{g}$
Mass of sample after converting metal completely to oxide $=0.452 \mathrm{g}$

David Collins
David Collins
Numerade Educator
03:56

Problem 94

Titanium(IV) oxide, $\mathrm{TiO}_{2}$, is heated in hydrogen gas to give water and a new titanium oxide, $\mathrm{Ti}_{x} \mathrm{O}_{y}$. If 1.598 $\mathrm{g}$ of $\mathrm{TiO}_{2}$ produces $1.438 \mathrm{g}$ of $\mathrm{Ti}_{x} \mathrm{O}_{y},$ what is the empirical formula of the new oxide?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:07

Problem 95

Potassium perchlorate is prepared by the following sequence of reactions:
$\mathrm{Cl}_{2}(\mathrm{g})+2 \mathrm{KOH}(\mathrm{aq}) \rightarrow \mathrm{KCl}(\mathrm{aq})+\mathrm{KClO}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)$
$3 \mathrm{KClO}(\mathrm{aq}) \rightarrow 2 \mathrm{KCl}(\mathrm{aq})+\mathrm{KClO}_{3}(\mathrm{aq})$
$4 \mathrm{KClO}_{3}(\mathrm{aq}) \rightarrow 3 \mathrm{KClO}_{4}(\mathrm{aq})+\mathrm{KCl}(\mathrm{aq})$
What mass of $\mathrm{Cl}_{2}(\mathrm{g})$ is required to produce $234 \mathrm{kg}$ of $\mathrm{KClO}_{4} ?$

David Collins
David Collins
Numerade Educator
05:22

Problem 96

Commercial sodium "hydrosulfite" is $90.1 \%$ $\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4} .$ The sequence of reactions used to prepare the compound is
$$\begin{array}{c}
\mathrm{Zn}(\mathrm{s})+2 \mathrm{SO}_{2}(\mathrm{g}) \rightarrow \mathrm{ZnS}_{2} \mathrm{O}_{4}(\mathrm{s}) \\
\mathrm{ZnS}_{2} \mathrm{O}_{4}(\mathrm{s})+\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq}) \rightarrow \mathrm{ZnCO}_{3}(\mathrm{s})+\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4}(\mathrm{aq})
\end{array}$$
(a) What mass of pure $\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4}$ can be prepared from
$125 \mathrm{kg}$ of $\mathrm{Zn}, 500 \mathrm{g}$ of $\mathrm{SO}_{2},$ and an excess of $\mathrm{Na}_{2} \mathrm{CO}_{3} ?$
(b) What mass of the commercial product would contain the $\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4}$ produced using the amounts of reactants in part (a)?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
00:56

Problem 97

What mass of lime, CaO, can be obtained by heating $125 \mathrm{kg}$ of limestone that is $95.0 \%$ by mass $\mathrm{CaCO}_{3} ?$
$$\mathrm{CaCO}_{3}(\mathrm{s}) \rightarrow \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g})$$

David Collins
David Collins
Numerade Educator
02:41

Problem 98

The elements silver, molybdenum, and sulfur combine to form $\mathrm{Ag}_{2} \mathrm{MoS}_{4} .$ What is the maximum mass of $\mathrm{Ag}_{2} \mathrm{MoS}_{4}$ that can be obtained if $8.63 \mathrm{g}$ of silver, $3.36 \mathrm{g}$ of molybdenum, and $4.81 \mathrm{g}$ of sulfur are combined?

David Collins
David Collins
Numerade Educator
09:24

Problem 99

A mixture of butene, $\mathrm{C}_{4} \mathrm{H}_{8},$ and butane, $\mathrm{C}_{4} \mathrm{H}_{10},$ is burned in air to give $\mathrm{CO}_{2}$ and water. Suppose you burn $2.86 \mathrm{g}$ of the mixture and obtain $8.80 \mathrm{g}$ of $\mathrm{CO}_{2}$ and $4.14 \mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O} .$ What are the mass percentages of butene and butane in the mixture?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
05:05

Problem 100

Cloth can be waterproofed by coating it with a silicone layer. This is done by exposing the cloth to $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}$ vapor. The silicon compound reacts with OH groups on the cloth to form a waterproofing film (density $=1.0 \mathrm{g} / \mathrm{cm}^{3}$ ) of $\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiO}\right]_{n},$ where $n$ is a large integer number.
$n\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}+2 n \mathrm{OH}^{-} \rightarrow$
$$
2 n \mathrm{Cl}^{-}+n \mathrm{H}_{2} \mathrm{O}+\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiO}\right]_{n}
$$
The coating is added layer by layer, each layer of $\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiO}\right]_{n}$ being $0.60 \mathrm{nm}$ thick. Suppose you want to waterproof a piece of cloth that is 3.00 m square, and you want 250 layers of waterproofing compound on the cloth. What mass of $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}$ do you need?

Ronald Prasad
Ronald Prasad
Numerade Educator
09:24

Problem 101

Copper metal can be prepared by roasting copper ore, which can contain cuprite $\left(\mathrm{Cu}_{2} \mathrm{S}\right)$ and $\operatorname{copper}(\mathrm{II})$ sulfide.
$$\begin{aligned}
\mathrm{Cu}_{2} \mathrm{S}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) & \rightarrow 2 \mathrm{Cu}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g}) \\
\mathrm{CuS}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) & \rightarrow \mathrm{Cu}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g})
\end{aligned}$$
Suppose an ore sample contains $11.0 \%$ impurity in addition to a mixture of $\mathrm{CuS}$ and $\mathrm{Cu}_{2} \mathrm{S}$ Heating $100.0 \mathrm{g}$ of the mixture produces $75.4 \mathrm{g}$ of copper metal with a purity of $89.5 \% .$ What is the weight percent of $\mathrm{CuS}$ in the ore? The weight percent of $\mathrm{Cu}_{2} \mathrm{S} ?$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:14

Problem 102

Which has the larger concentration of hydronium ions, 0.015 M HCl or aqueous HCl with a pH of $1.2 ?$

Angelina Chavez
Angelina Chavez
Numerade Educator
05:27

Problem 103

The mineral dolomite contains magnesium carbonate.
$$\begin{aligned}
\operatorname{MgCO}_{3}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) & \rightarrow \\
& \mathrm{CO}_{2}(\mathrm{g})+\mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)
\end{aligned}$$
(a) Write the net ionic equation for the reaction of $\mathrm{MgCO}_{3}$ and $\mathrm{HCl}(\mathrm{aq})$
(b) What type of reaction is this?
(c) What mass of MgCO $_{3}$ will react with $125 \mathrm{mL}$ of $\mathrm{HCl}(\mathrm{aq})$ with a $\mathrm{pH}$ of $1.56 ?$

Angelina Chavez
Angelina Chavez
Numerade Educator
01:47

Problem 104

An Alka-Seltzer tablet contains exactly $100 .$ mg of citric acid, $\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7},$ plus some sodium bicarbonate. If the following reaction occurs, what mass of sodium bicarbonate must the tablet also contain if citric acid is completely consumed by the following reaction?
$$\begin{aligned}
\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq}) &+3 \mathrm{NaHCO}_{3}(\mathrm{aq}) \rightarrow \\
& 3 \mathrm{H}_{2} \mathrm{O}(\ell)+3 \mathrm{CO}_{2}(\mathrm{g})+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})
\end{aligned}$$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:18

Problem 105

Sodium bicarbonate and acetic acid react according to the equation
$\mathrm{NaHCO}_{3}(\mathrm{aq})+\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}(\mathrm{aq}) \rightarrow$
$$
\mathrm{NaCH}_{3} \mathrm{CO}_{2}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell)
$$
What mass of sodium acetate can be obtained from mixing $15.0 \mathrm{g}$ of $\mathrm{NaHCO}_{3}$ with $125 \mathrm{mL}$ of $0.15 \mathrm{M}$ acetic acid?

Angelina Chavez
Angelina Chavez
Numerade Educator
02:30

Problem 106

A noncarbonated soft drink contains an unknown amount of citric acid, $\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7} .$ If $100 .$ mL of the soft drink requires $33.51 \mathrm{mL}$ of $0.0102 \mathrm{M} \mathrm{NaOH}$ to neutralize the citric acid completely, what mass of citric acid does the soft drink contain per $100 .$ mL? The reaction of citric acid and $\mathrm{NaOH}$ is
$\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{NaOH}(\mathrm{aq}) \rightarrow$
$$
\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{H}_{2} \mathrm{O}(\ell)
$$

Banhishikha Sinha
Banhishikha Sinha
Numerade Educator
09:49

Problem 107

Sodium thiosulfate, $\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3},$ is used as a "fixer" in black-and-white photography. Suppose you have a bottle of sodium thiosulfate and want to determine its purity. The thiosulfate ion can be oxidized with $\mathrm{I}_{2}$ according to the balanced, net ionic equation
$$
\mathrm{I}_{2}(\mathrm{aq})+2 \mathrm{S}_{2} \mathrm{O}_{3}^{2-}(\mathrm{aq}) \rightarrow 2 \mathrm{I}^{-}(\mathrm{aq})+\mathrm{S}_{4} \mathrm{O}_{6}^{2-}(\mathrm{aq})
$$
If you use $40.21 \mathrm{mL}$ of $0.246 \mathrm{M} \mathrm{I}_{2}$ in a titration, what is the weight percent of $\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3}$ in a $3.232-\mathrm{g}$ sample of impure material?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:07

Problem 108

You have a mixture of oxalic acid, $\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4},$ and another solid that does not react with sodium hydroxide. If $29.58 \mathrm{mL}$ of $0.550 \mathrm{M} \mathrm{NaOH}$ is required to titrate the oxalic acid in the 4.554 -g sample to the second equivalence point, what is the mass percent of oxalic acid in the mixture? Oxalic acid and NaOH react according to the equation
$\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow$
$$
\mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell)
$$

Ronald Prasad
Ronald Prasad
Numerade Educator
05:52

Problem 109

(a) What is the pH of a 0.105 M HCl solution?
(b) What is the hydronium ion concentration in a solution with a pH of $2.56 ?$ Is the solution acidic or basic?
(c) A solution has a pH of $9.67 .$ What is the hydronium ion concentration in the solution? Is the solution acidic or basic?
(d) A 10.0 -mL sample of $2.56 \mathrm{M}$ HCl is diluted with water to $250 .$ mL. What is the $\mathrm{pH}$ of the dilute solution?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:31

Problem 110

A solution of hydrochloric acid has a volume of $125 \mathrm{mL}$ and a $\mathrm{pH}$ of $2.56 .$ What mass of $\mathrm{NaHCO}_{3}$ must be added to completely consume the HCl?

Ronald Prasad
Ronald Prasad
Numerade Educator
02:58

Problem 111

One half liter $(500 . \mathrm{mL})$ of $2.50 \mathrm{M} \mathrm{HCl}$ is mixed with $250 .$ mL of 3.75 M HCl. Assuming the total solution volume after mixing is $750 .$ mL, what is the concentration of hydrochloric acid in the resulting solution? What is its pH?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
05:40

Problem 112

A solution of hydrochloric acid has a volume of $250 .$ mL and a pH of $1.92 .$ Exactly $250 .$ mL of $0.0105 \mathrm{M} \mathrm{NaOH}$ is added. What is the pH of the resulting solution?

Angelina Chavez
Angelina Chavez
Numerade Educator
10:05

Problem 113

You place $2.56 \mathrm{g}$ of $\mathrm{CaCO}_{3}$ in a beaker containing 250. mL of 0.125 M HCl. When the reaction has ceased, does any calcium carbonate remain? What mass of $\mathrm{CaCl}_{2}$ can be produced?
$\mathrm{CaCO}_{3}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow$
$$
\mathrm{CaCl}_{2}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell)
$$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
08:52

Problem 114

The cancer chemotherapy drug cisplatin, $\operatorname{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}$ can be made by reacting $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{PtCl}_{4}$ with ammonia in aqueous solution. Besides cisplatin, the other product is $\mathrm{NH}_{4} \mathrm{Cl}$.
(a) Write a balanced equation for this reaction.
(b) To obtain $12.50 \mathrm{g}$ of cisplatin, what mass of $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{PtCl}_{4}$ is required? What volume of $0.125 \mathrm{M} \mathrm{NH}_{3}$ is required?
(c) Cisplatin can react with the organic compound pyridine, $\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N},$ to form a new compound.
$$
\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}(\mathrm{aq})+x \mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}(\mathrm{aq}) \rightarrow
$$
$$
\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\left(\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}\right)_{x}(\mathrm{s})
$$
Suppose you treat $0.150 \mathrm{g}$ of cisplatin with what you believe is an excess of liquid pyridine $(1.50 \mathrm{mL} ; \bar{d}=$ $0.979 \mathrm{g} / \mathrm{mL}) .$ When the reaction is complete, you can find out how much pyridine was not used by titrating the solution with standardized HCl. If 37.0 mL of $0.475 \mathrm{M} \mathrm{HCl}$ is required to titrate the excess pyridine,
$$
\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{C}_{5} \mathrm{H}_{5} \mathrm{NH}^{+}(\mathrm{aq})+\mathrm{Cl}^{-}(\mathrm{aq})
$$
what is the formula of the unknown compound $\mathrm{Pt}\left(\mathrm{NH}_{3}\right)_{2} \mathrm{Cl}_{2}\left(\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{N}\right)_{x}$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:47

Problem 115

You need to know the volume of water in a small swimming pool, but, owing to the pool's irregular shape, it is not a simple matter to determine its dimensions and calculate the volume. To solve the problem, you stir in a solution of a dye ( $1.0 \mathrm{g}$ of methylene blue, $\left.\mathrm{C}_{16} \mathrm{H}_{18} \mathrm{ClN}_{3} \mathrm{S}, \text { in } 50.0 \mathrm{mL} \text { of water }\right) .$ After the dye has
mixed with the water in the pool, you take a sample of the water. Using a spectrophotometer, you determine that the concentration of the dye in the pool is $4.1 \times$ $10^{-8} \mathrm{M} .$ What is the volume of water in the pool?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
06:32

Problem 116

Calcium and magnesium carbonates occur together in the mineral dolomite. Suppose you heat a sample of the mineral to obtain the oxides, $\mathrm{CaO}$ and $\mathrm{MgO}$, and then treat the oxide sample with hydrochloric acid. If $7.695 \mathrm{g}$ of the oxide sample requires $125 \mathrm{mL}$ of $2.55 \mathrm{M} \mathrm{HCl}$,
$$\begin{array}{l}
\mathrm{CaO}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{CaCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell) \\
\mathrm{MgO}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)
\end{array}$$
What is the weight percent of each oxide (CaO and $\mathrm{MgO})$ in the sample?

Rashmi Sinha
Rashmi Sinha
Numerade Educator
06:03

Problem 117

Gold can be dissolved from gold-bearing rock by treating the rock with sodium cyanide in the presence of oxygen.
$4 \mathrm{Au}(\mathrm{s})+8 \mathrm{NaCN}(\mathrm{aq})+\mathrm{O}_{2}(\mathrm{g})+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow$
$$
4 \mathrm{NaAu}(\mathrm{CN})_{2}(\mathrm{aq})+4 \mathrm{NaOH}(\mathrm{aq})
$$
(a) Name the oxidizing and reducing agents in this reaction. What has been oxidized, and what has been reduced?
(b) If you have exactly one metric ton ( 1 metric ton $=1000 \mathrm{kg})$ of gold-bearing rock, what volume of $0.075 \mathrm{M} \mathrm{NaCN},$ in liters, do you need to extract the gold if the rock is $0.019 \%$ gold?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
07:52

Problem 118

You mix $25.0 \mathrm{mL}$ of $0.234 \mathrm{M} \mathrm{FeCl}_{3}$ with $42.5 \mathrm{mL}$ of $0.453 \mathrm{M} \mathrm{NaOH}$.
(a) What mass of $\mathrm{Fe}(\mathrm{OH})_{3}$ (in grams) will precipitate from this reaction mixture?
(b) One of the reactants $\left(\mathrm{FeCl}_{3} \text { or } \mathrm{NaOH}\right)$ is present in a stoichiometric excess. What is the molar concentration of the excess reactant remaining in solution after $\mathrm{Fe}(\mathrm{OH})_{3}$ has been precipitated?

Ronald Prasad
Ronald Prasad
Numerade Educator
03:43

Problem 119

Suppose you dilute $25.0 \mathrm{mL}$ of a $0.110 \mathrm{M}$ solution of $\mathrm{Na}_{2} \mathrm{CO}_{3}$ to exactly $100.0 \mathrm{mL}$. You then take exactly $10.0 \mathrm{mL}$ of this diluted solution and add it to a $250-$ mL volumetric flask. After filling the volumetric flask to the mark with distilled water (indicating the volume of the new solution is $250 . \mathrm{mL}$ ), what is the concentration of the diluted $\mathrm{Na}_{2} \mathrm{CO}_{3}$ solution?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
08:40

Problem 120

In some laboratory analyses, the preferred technique is to dissolve a sample in an excess of acid or base and then "back-titrate" the excess with a standard base or acid. This technique is used to assess the purity of a sample of $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4} .$ Suppose you dissolve
a 0.475 -g sample of impure $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$ in aqueous $\mathrm{KOH}$
$$\begin{aligned}
\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}(\mathrm{aq}) &+2 \mathrm{KOH}(\mathrm{aq}) \rightarrow \\
& 2 \mathrm{NH}_{3}(\mathrm{aq})+2 \mathrm{K}_{2} \mathrm{SO}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell)
\end{aligned}$$
The $\mathrm{NH}_{3}$ liberated in the reaction is distilled from the solution into a flask containing $50.0 \mathrm{mL}$ of $0.100 \mathrm{M}$ HCl. The ammonia reacts with the acid to produce $\mathrm{NH}_{4} \mathrm{Cl},$ but not all of the $\mathrm{HCl}$ is used in this reaction. The amount of excess acid is determined by titrating the solution with standardized NaOH. This titration consumes $11.1 \mathrm{mL}$ of $0.121 \mathrm{M} \mathrm{NaOH}$. What is the weight percent of $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4}$ in the $0.475 \mathrm{-g}$ sample?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
08:50

Problem 121

You wish to determine the weight percent of copper in a copper-containing alloy. After dissolving a $0.251-\mathrm{g}$ sample of the alloy in acid, an excess of KI is added, and the $\mathrm{Cu}^{2+}$ and $\mathrm{I}^{-}$ ions undergo the reaction
$$
2 \mathrm{Cu}^{2+}(\mathrm{aq})+5 \mathrm{I}^{-}(\mathrm{aq}) \rightarrow 2 \mathrm{CuI}(\mathrm{s})+\mathrm{I}_{3}^{-}(\mathrm{aq})
$$
The liberated $I_{3}-$ is titrated with sodium thiosulfate according to the equation
$$
\mathrm{I}_{3}^{-}(\mathrm{aq})+2 \mathrm{S}_{2} \mathrm{O}_{3}^{2-}(\mathrm{aq}) \rightarrow \mathrm{S}_{4} \mathrm{O}_{6}^{2-}(\mathrm{aq})+3 \mathrm{I}^{-}(\mathrm{aq})
$$
(a) Designate the oxidizing and reducing agents in the two reactions above.
(b) If 26.32 mL of $0.101 \mathrm{M} \mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3}$ is required for titration to the equivalence point, what is the weight percent of Cu in the alloy?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
05:07

Problem 122

A compound has been isolated that can have either of two possible formulas: (a) $\mathrm{K}\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{2}\left(\mathrm{H}_{2} \mathrm{O}\right)_{2}\right]$ or
(b) $\mathrm{K}_{3}\left[\mathrm{Fe}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right] .$ To find which is correct, you dissolve a weighed sample of the compound in acid and then titrate the oxalate ion $(\mathrm{C}_{2} \mathrm{O}_{4}^{2-},$ which in acid becomes $\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}$ ) with potassium permanganate, $\mathrm{KMnO}_{4}$ (the source of the $\mathrm{MnO}_{4}^{-}$ ion). The balanced, net ionic equation for the titration is $$\begin{aligned}
5 \mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+& 2 \mathrm{MnO}_{4}^{-}(\mathrm{aq})+6 \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq}) \rightarrow \\
& 2 \mathrm{Mn}^{2+}(\mathrm{aq})+10 \mathrm{CO}_{2}(\mathrm{g})+14 \mathrm{H}_{2} \mathrm{O}(\ell)
\end{aligned}$$
Titration of $1.356 \mathrm{g}$ of the compound requires 34.50 mL of $0.108 \mathrm{M} \mathrm{KMnO}_{4} .$ Which is the correct formula of the iron-containing compound: (a) or (b)?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:07

Problem 123

Chromium(III) ion forms many compounds with ammonia. To find the formula of one of these compounds, you titrate the $\mathrm{NH}_{3}$ in the compound with standardized acid.
$\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{x} \mathrm{Cl}_{3}(\mathrm{aq})+x \mathrm{HCl}(\mathrm{aq}) \rightarrow$
$$
x \mathrm{NH}_{4}^{+}(\mathrm{aq})+\mathrm{Cr}^{3+}(\mathrm{aq})+(x+3) \mathrm{Cl}^{-}(\mathrm{aq})
$$
Assume that $24.26 \mathrm{mL}$ of $1.500 \mathrm{M} \mathrm{HCl}$ is used to titrate $1.580 \mathrm{g}$ of $\mathrm{Cr}\left(\mathrm{NH}_{3}\right)_{x} \mathrm{Cl}_{3} .$ What is the value of $x ?$

Angelina Chavez
Angelina Chavez
Numerade Educator
03:05

Problem 124

Thioridazine, $\mathrm{C}_{21} \mathrm{H}_{26} \mathrm{N}_{2} \mathrm{S}_{2},$ is a pharmaceutical agent used to regulate dopamine. (Dopamine, a neurotransmitter, affects brain processes that control movement, emotional response, and ability to experience pleasure and pain.) A chemist can analyze a sample of the pharmaceutical for the thioridazine content by decomposing it to convert the sulfur in the compound to sulfate ion. This is then "trapped" as water-insoluble barium sulfate (see Figure 4.6 ).
$$\begin{aligned}
\mathrm{SO}_{4}{^3}{^-}
(\text { aq, from thioridazine })+& \mathrm{BaCl}_{2}(\mathrm{aq}) \rightarrow \\
& \mathrm{BaSO}_{4}(\mathrm{s})+2 \mathrm{Cl}^{-}(\mathrm{aq})
\end{aligned}$$
Suppose a 12 -tablet sample of the drug yielded 0.301 g of BaSO, What is the thioridazine content, in milligrams, of each tablet?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:26

Problem 125

A herbicide contains $2,4-\mathrm{D}$ ( 2,4 -dichlorophenoxy-acetic acid), $\mathrm{C}_{8} \mathrm{H}_{6} \mathrm{Cl}_{2} \mathrm{O}_{3} .$ A $1.236-\mathrm{g}$ sample of the herbicide was decomposed to liberate the chlorine as $\mathrm{Cl}^{-}$ ion. This was precipitated as AgCl, with a mass of 0.1840g. What is the the sample?
(FIGURE CANNOT COPY)

David Collins
David Collins
Numerade Educator
07:05

Problem 126

Sulfuric acid is listed in a catalog with a concentration of $95-98 \% .$ A bottle of the acid in the stockroom states that $1.00 \mathrm{L}$ has a mass of $1.84 \mathrm{kg} .$ To determine the concentration of sulfuric acid in the stockroom bottle, a student dilutes $5.00 \mathrm{mL}$ to $500 .$ mL. She then takes four $10.00-\mathrm{mL}$ samples and titrates each with standardized sodium hydroxide $(c=0.1760 \mathrm{mol} / \mathrm{L})$ $\begin{array}{lcccc}\text { Sample } & 1 & 2 & 3 & 4 \\ \text { Volume NaOH (mL) } & 20.15 & 21.30 & 20.40 & 20.35\end{array}$
(a) What is the average concentration of the diluted sulfuric acid sample?
(b) What is the mass percent of $\mathrm{H}_{2} \mathrm{SO}_{4}$ in the original bottle of the acid?

Himanshu Kushwaha
Himanshu Kushwaha
Numerade Educator
View

Problem 127

Anhydrous calcium chloride is a good drying agent as it will rapidly pick up water. Suppose you have stored some carefully dried $\mathrm{CaCl}_{2}$ in a dessicator. Unfortunately, someone did not close the top of the dessicator tightly, and the $\mathrm{CaCl}_{2}$ became partially hydrated. A 150 -g sample of this partially hydrated material was dissolved in $80 \mathrm{g}$ of hot water. When the solution was cooled to $20^{\circ} \mathrm{C}, 74.9 \mathrm{g}$ of $\mathrm{CaCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}$
precipitated. Knowing the solubility of calcium chloride in water at $20^{\circ} \mathrm{C}$ is $74.5 \mathrm{g} \mathrm{CaCl}_{2} / 100 \mathrm{g}$ water, determine the water content of the 150 -g sample of partially hydrated calcium chloride (in moles of water per mole of $\mathrm{CaCl}_{2}$ ).

Victor Salazar
Victor Salazar
Numerade Educator
03:03

Problem 128

A sample consisting of a mixture of iron and iron(III) oxide was dissolved completely in acid (which converted the iron to iron(III) ions.) After adding a reducing agent to ensure that all of the iron was in the form of iron(II) ions, the solution was titrated with the standardized $\mathrm{KMnO}_{4}(0.04240 \mathrm{M})$ $37.50 \mathrm{mL}$ of the $\mathrm{KMnO}_{4}$ solution was required. Calculate the mass percent of $\mathrm{Fe}$ and $\mathrm{Fe}_{2} \mathrm{O}_{3}$ in the $0.5510-\mathrm{g}$ sample. (See Example 4.12 for the reaction of iron(II) and $\mathrm{KMnO}_{4}$.)

Ronald Prasad
Ronald Prasad
Numerade Educator
05:04

Problem 129

Phosphate in urine can be determined by spectrophotometry. After removing protein from the sample, it is treated with a molybdenum compound to give, ultimately, a deep blue polymolybdate. The absorbance of the blue polymolybdate can be measured at 650 nm and is directly related to the urine phosphate concentration. A 24 -hour urine sample was collected from a patient; the volume of urine was 1122 mL. The phosphate in a $1.00 \mathrm{mL}$ portion of the urine sample was converted to the blue polymolybdate (P) and diluted to 50.00 mL. A calibration curve was prepared using phosphate-containing solutions.
(TABLE CANNOT COPY)
(a) What are the slope and intercept of the calibration curve?
(b) What is the mass of phosphorus per liter of urine?
(c) What mass of phosphate did the patient excrete per day?

Ronald Prasad
Ronald Prasad
Numerade Educator
View

Problem 130

A $4.000-\mathrm{g}$ sample containing $\mathrm{KCl}$ and $\mathrm{KClO}_{4}$ was dissolved in sufficient water to give $250.00 \mathrm{mL}$ of solution. A 50.00 -mL portion of the solution required $41.00 \mathrm{mL}$ of $0.0750 \mathrm{M} \mathrm{AgNO}_{3}$ in a Mohr titration (page 186 ). Next, a 25.00 -mL portion of the original solution was treated with $\mathrm{V}_{2}\left(\mathrm{SO}_{4}\right)_{3}$ to reduce the perchlorate ion to chloride,
$8 \mathrm{V}^{3+}(\mathrm{aq})+\mathrm{CIO}_{4}{^-}(\mathrm{aq})+12 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow$
$$
\mathrm{Cl}^{-}(\mathrm{aq})+8 \mathrm{VO}^{2+}(\mathrm{aq})+8 \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq})
$$
and the resulting solution was titrated with AgNO $_{3} .$ This titration required $38.12 \mathrm{mL}$ of $0.0750 \mathrm{M} \mathrm{AgNO}_{3} .$ What is the mass percent of KCl and $\mathrm{KClO}_{4}$ in the mixture?

Victor Salazar
Victor Salazar
Numerade Educator
02:20

Problem 131

Two beakers sit on a balance; the total mass is $167.170 \mathrm{g} .$ One beaker contains a solution of $\mathrm{KI}$ the other contains a solution of $\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2} .$ When the solution in one beaker is poured completely into the other, the following reaction occurs:
$$
2 \mathrm{KI}(\mathrm{aq})+\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq}) \rightarrow 2 \mathrm{KNO}_{3}(\mathrm{aq})+\mathrm{PbI}_{2}(\mathrm{s})
$$
(FIGURE CANNOT COPY)
What is the total mass of the beakers and solutions after reaction? Explain completely.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
07:58

Problem 132

A weighed sample of iron (Fe) is added to liquid bromine $\left(\mathrm{Br}_{2}\right)$ and allowed to react completely. The reaction produces a single product, which can be isolated and weighed. The experiment was repeated a number of times with different masses of iron but with the same mass of bromine. (See the graph below.)
(FIGURE CANNOT COPY)
(a) What mass of $\mathrm{Br}_{2}$ is used when the reaction consumes $2.0 \mathrm{g}$ of Fe?
(b) What is the mole ratio of $\mathrm{Br}_{2}$ to Fe in the reaction?
(c) What is the empirical formula of the product?
(d) Write the balanced chemical equation for the reaction of iron and bromine.
(e) What is the name of the reaction product?
(f) Which statement or statements best describe the experiments summarized by the graph?
(i) When $1.00 \mathrm{g}$ of Fe is added to the $\mathrm{Br}_{2},$ Fe is the limiting reagent.
(ii) When $3.50 \mathrm{g}$ of $\mathrm{Fe}$ is added to the $\mathrm{Br}_{2}$, there is an excess of Br
(iii) When $2.50 \mathrm{g}$ of $\mathrm{Fe}$ is added to the $\mathrm{Br}_{2},$ both reactants are used up completely.
(iv) When $2.00 \mathrm{g}$ of $\mathrm{Fe}$ is added to the $\mathrm{Br}_{2}, 10.0 \mathrm{g}$ of product is formed. The percent yield must therefore be $20.0 \%$

Ronald Prasad
Ronald Prasad
Numerade Educator
04:02

Problem 133

Let us explore a reaction with a limiting reactant. (See ChemistryNow Screens 4.4 and $4.5 .$ ) Here, zinc metal is added to a flask containing aqueous HCl, and $\mathrm{H}_{2}$ gas is a product.
$$
\mathrm{Zn}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{ZnCl}_{2}(\mathrm{aq})+\mathrm{H}_{2}(\mathrm{g})
$$
The three flasks each contain 0.100 mol of HCl. Zinc is added to each flask in the following quantities.
Flask $1: 7.00 \mathrm{g}$ Zn
Flask 2: 3.27 g $\mathrm{Zn}$
Flask $3: 1.31 \mathrm{g}$ Zn
(FIGURE CANNOT COPY)
When the reactants are combined, the $\mathrm{H}_{2}$ inflates the balloon attached to the flask. The results are as follows:
Flask 1: Balloon inflates completely, but some Zn remains when inflation ceases. Flask 2: Balloon inflates completely. No Zn remains. Flask 3: Balloon does not inflate completely. No Zn remains.
Explain these results. Perform calculations that support your explanation.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
00:27

Problem 134

The reaction of aluminum and bromine is pictured in Figure 2.12 and below. The white solid on the lip of the beaker at the end of the reaction is $\mathrm{Al}_{2} \mathrm{Br}_{6}$. In the reaction pictured below, which was the limiting reactant, Al or Br $_{2} ?$ (See ChemistryNow Screen 4.2.)
(FIGURE CANNOT COPY)

David Collins
David Collins
Numerade Educator
01:31

Problem 135

Two students titrate different samples of the same solution of HCl using $0.100 \mathrm{M} \mathrm{NaOH}$ solution and phenolphthalein indicator (see Figure 4.14 ). The first student pipets $20.0 \mathrm{mL}$ of the HCl solution into a flask, adds $20 \mathrm{mL}$ of distilled water and a few drops of phenolphthalein solution, and titrates until a lasting pink color appears. The second student pipets 20.0 mL of the HCl solution into a flask, adds $60 \mathrm{mL}$ of distilled water and a few drops of phenolphthalein solution, and titrates to the first lasting pink color. Each student correctly calculates the molarity of an HCl solution. What will the second student's result be?
(a) four times less than the first student's result
(b) four times greater than the first student's result
(c) two times less than the first student's result
(d) two times greater than the first student's result
(e) the same as the first student's result

Angelina Chavez
Angelina Chavez
Numerade Educator
05:07

Problem 136

A video on Screen 4.12 of ChemistryNow shows the reaction of $\mathrm{Fe}^{2+}$ with $\mathrm{MnO}_{4}{^-}$ in aqueous solution.
(a) What is the balanced equation for the reaction that occurred?
(b) What is the oxidizing agent, and what is the reducing agent?
(c) Equal volumes of $\mathrm{Fe}^{2+}$ - containing solution and $\mathrm{MnO}_{4}{^-}$ -containing solution were mixed. The amount of $\mathrm{Fe}^{2+}$ was just sufficient to consume all of the $\mathrm{MnO}_{4}{^-} .$ Which ion $\left(\mathrm{Fe}^{2+} \text { or } \mathrm{MnO}_{4}{^-}\right)$ was initially present in larger concentration?

Ahmed Ali
Ahmed Ali
Numerade Educator
02:18

Problem 137

In some states, a person will receive a "driving while intoxicated" (DWI) ticket if the blood alcohol level (BAL) is 100 mg per deciliter (dL) of blood or higher. Suppose a person is found to have a BAL of 0.033 mol of ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ per liter of blood. Will the person receive a DWI ticket?

Ronald Prasad
Ronald Prasad
Numerade Educator