Chemistry A Molecular Approach

Nivaldo J. Tro

Chapter 3

Molecules, Compounds, and Chemical Equations - all with Video Answers

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Chapter Questions

Problem 1

How do the properties of compounds compare to the properties of the elements from which the compounds are composed?

Rikhil Makwana

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Problem 2

What is a chemical bond? Explain the difference between an ionic bond and a covalent bond.

James Irizarry

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Problem 3

Explain the different ways to represent compounds. Why are there so many?

Rikhil Makwana

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Problem 4

What is the difference between an empirical formula and a molecular formula?

James Irizarry

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Problem 5

Define and provide an example for each of the following: atomic element, molecular element, ionic compound, molecular compound.

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Problem 6

Explain how to write a formula for an ionic compound given the names of the metal and nonmetal (or polyatomic ion) in the compound.

James Irizarry

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Problem 7

Explain how to name binary ionic compounds. How do you name an ionic compound if it contains a polyatomic ion?

Rikhil Makwana

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Problem 8

Why do the names of some ionic compounds include the charge of the metal ion while others do not?

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Problem 9

Explain how to name molecular inorganic compounds.

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Problem 10

How many atoms are specified by each of these prefixes: $mono{-,}$ $di{-,} tri{-,}$ $tetra{-,}$ $penta{-,}$ $hexa{-?}$

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Problem 11

Explain how to name binary and oxyacids.

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Problem 12

What is the formula mass for a compound? Why is it useful?

James Irizarry

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Problem 13

Explain how you can use the information in a chemical formula to determine how much of a particular element is present in a given amount of a compound. Provide some examples of why this might be important.

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Problem 14

What is mass percent composition? Why is it useful?

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Problem 15

What kinds of conversion factors are inherent in chemical formulas? Provide an example.

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Problem 16

What kind of chemical formula can be obtained from experimental data showing the relative masses of the elements in a compound?

James Irizarry

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Problem 17

How can a molecular formula be obtained from an empirical formula? What additional information is required?

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Problem 18

What is combustion analysis? What is it used for?

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Problem 19

Which elements are normally present in organic compounds?

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Problem 20

What is the difference between an alkane, an alkene, and an alkyne?

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Problem 21

What are functionalized hydrocarbons? Cite an example of a functionalized hydrocarbon.

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Problem 22

Write a generic formula for each of the families of organic compounds.
\begin{equation}\begin{array}{ll}{\text { a. alcohols }} & {\text { e. carboxylic acids }} \\ {\text { b. ethers }} & {\text { f. esters }} \\ {\text { c. aldehydes }} & {\text { g. amines }} \\ {\text { d. ketones }}\end{array}\end{equation}

James Irizarry

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Problem 23

Determine the number of each type of atom in each formula.
\begin{equation}
\quad \text { a. }\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2} \quad \text { b. } \mathrm{BaCl}_{2} \quad \text { c. } \mathrm{Fe}\left(\mathrm{NO}_{2}\right)_{2} \quad \text { d. } \mathrm{Ca}(\mathrm{OH})_{2}
\end{equation}

Rikhil Makwana

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Problem 24

Determine the number of each type of atom in each formula.
\begin{equation} \quad \text { a. }\mathrm{Ca}\left(\mathrm{NO}_{2}\right)_{2} \quad \text { b. } \operatorname{CuSO}_{4} \quad \text { c. } \mathrm{Al}\left(\mathrm{NO}_{3}\right)_{3} \quad \text { d. } \mathrm{Mg}\left(\mathrm{HCO}_{3}\right)_{2}\end{equation}

James Irizarry

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Problem 25

Write a chemical formula for each molecular model. (See Appendix IIA for color codes.)

KC

Kara Cecil

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Problem 26

Write a chemical formula for each molecular model. (See Appendix IIA for color codes.)

James Irizarry

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Problem 27

Classify each element as atomic or molecular.
\begin{equation}\begin{array}{l}{\text { a. neon } \quad \text { b. fluorine } \quad \text { c. potassium } \quad \text { d. nitrogen }}\end{array}\end{equation}

Rikhil Makwana

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Problem 28

Identify the elements that have molecules as their basic units.
\begin{equation}\begin{array}{l}{\text { a. hydrogen b. iodine } \quad \text { c. lead } \quad \text { d. oxygen }}\end{array}\end{equation}

James Irizarry

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Problem 29

Classify each compound as ionic or molecular.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{CO}_{2} \quad \text { b. } \mathrm{NiCl}_{2} \quad \text { c. Nal } \quad \text { d. } \mathrm{PCl}_{3}}\end{array}\end{equation}

Rikhil Makwana

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Problem 30

Classify each compound as ionic or molecular.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{CF}_{2} \mathrm{Cl}_{2} \quad \text { b. } \mathrm{CCl}_{4} \quad \text { c. PtO }_{2} \quad \text { d. SO }_{3}}\end{array}\end{equation}

James Irizarry

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Problem 31

Based on the molecular views, classify each substance as an atomic element, a molecular element, an ionic compound, or a molecular compound.

Rikhil Makwana

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Problem 32

Based on the molecular views, classify each substance as an atomic element, a molecular element, an ionic compound, or a molecular compound.

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Problem 33

Write a formula for the ionic compound that forms between each pair of elements.
\begin{equation}\begin{array}{ll}{\text { a. calcium and oxygen }} & {\text { b. zinc and sulfur }} \\ {\text { c. rubidium and bromine }} & {\text { d. aluminum and oxygen }}\end{array}\end{equation}

Rikhil Makwana

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Problem 34

Write a formula for the ionic compound that forms between each pair of elements.
\begin{equation}\begin{array}{ll}{\text { a. silver and chlorine }} & {\text { b. sodium and sulfur }} \\ {\text { c. aluminum and sulfur }} & {\text { d. potassium and chlorine }}\end{array}\end{equation}

James Irizarry

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Problem 35

Write a formula for the compound that forms between calcium and each polyatomic ion.
\begin{equation}\begin{array}{ll}{\text { a. hydroxide }} & {\text { b. chromate }} \\ {\text { c. phosphate }} & {\text { d. cyanide }}\end{array}\end{equation}

Rikhil Makwana

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Problem 36

Write a formula for the compound that forms between potassium and each polyatomicion.
\begin{equation}\begin{array}{ll}{\text { a. carbonate }} & {\text { b. phosphate }} \\ {\text { c. hydrogen phosphate }} & {\text { d. acetate }}\end{array}\end{equation}

James Irizarry

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Problem 37

Name each ionic compound.
\begin{equation}\quad \text { a. }
\mathrm{Mg}_{3} \mathrm{N}_{2} \quad \text { b. KF } \quad \text { c. } \mathrm{Na}_{2} \mathrm{O} \\ \text { d. }\mathrm{Li}_{2} \mathrm{S} \quad \text { e. } \mathrm{CsF} \quad \text { f. } \mathrm{KI}\end{equation}

Rikhil Makwana

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Problem 38

Name each ionic compound.
\begin{equation} \quad \text { a. }\operatorname{SnCl}_{4} \quad \text { b. } \mathrm{PbI}_{2} \quad \text { c. } \mathrm{Fe}_{2} \mathrm{O}_{3} \\ \quad \text { d. } \mathrm{CuI}_{2} \quad \text { e. HgBr }_{2} \quad \text { f. } \operatorname{CrCl}_{2}\end{equation}

James Irizarry

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Problem 39

Give each ionic compound an appropriate name.
\begin{equation} \quad \text { a. }\mathrm{SnO}
\quad \text { b. } \mathrm{Cr}_{2} \mathrm{S}_{3} \quad \text { c. RbI } \quad \text { d. } \operatorname{BaBr}_{2}\end{equation}

Rikhil Makwana

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Problem 40

Give each ionic compound an appropriate name.
\begin{equation}\begin{array}{l}{\text { a. BaS } \quad \text { b. FeCl }_{3}} \quad \text { c. }
\mathrm{PbI}_{4} \quad \text { d. } \operatorname{SrBr}_{2} \end{array}\end{equation}

Jennifer Hudspeth

Jennifer Hudspeth

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Problem 41

Name each ionic compound containing a polyatomic ion.
\begin{equation}\begin{array}{ll}{\text { a. } \mathrm{CuNO}_{2}} & {\text { b. } \operatorname{Mg}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2}} \\ {\text { c. } \mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}} & {\text { d. } \mathrm{Pb}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2}}\end{array}\end{equation}

Rikhil Makwana

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Problem 42

Name each ionic compound containing a polyatomic ion.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{Ba}(\mathrm{OH})_{2} \quad \text { b. } \mathrm{NH}_{4} \mathrm{I}} & {\text { c. } \mathrm{NaBrO}_{4}} \quad \text { d. } \mathrm{Fe}(\mathrm{OH})_{3}\end{array}\end{equation}

James Irizarry

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Problem 43

Write the formula for each ionic compound.
\begin{equation}\begin{array}{l}{\text { a. sodium hydrogen sulfite }} \\ {\text { b. lithium permanganate }} \\ {\text { c. silver nitrate }} \\ {\text { d. potassium sulfate }} \\ {\text { e. rubidium hydrogen sulfate }} \\ {\text { f. potassium hydrogen carbonate }}\end{array}\end{equation}

Rikhil Makwana

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Problem 44

Write the formula for each ionic compound.
\begin{equation}\begin{array}{ll}{\text { a. copper (II) chloride }} & {\text { b. copper (I) iodate }} \\ {\text { c. lead(II) chromate }} & {\text { d. calcium fluoride }} \\ {\text { e. potassium hydroxide }} & {\text { f. iron(II) phosphate }}\end{array}\end{equation}

James Irizarry

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Problem 45

Write the name from the formula or the formula from the name for each hydrated ionic compound.
\begin{equation}\begin{array}{llll}{\text { a. } \cos \mathrm{O}_{4} \cdot 7 \mathrm{H}_{2} \mathrm{O}} & {\text { b. }} {\text { iridium(II) bromide tetrahydrate }} \\ {\text { c. } \mathrm{Mg}\left(\mathrm{BrO}_{3}\right)_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}} & {\text { d. potassium carbonate dihydrate }}\end{array}\end{equation}

Rikhil Makwana

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Problem 46

Write the name from the formula or the formula from the name for each hydrated ionic compound.
\begin{equation}\begin{array}{ll}{\text { a. cobalt(II) phosphate octahydrate }} & {\text { b. } \operatorname{BeCl}_{2} \cdot 2 \mathrm{H}_{2} \mathrm{O}} \\ {\text { c. chromium(II) phosphate trihydrate }} & {\text { d. } \operatorname{LiNO}_{2} \cdot \mathrm{H}_{2} \mathrm{O}}\end{array}\end{equation}

James Irizarry

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Problem 47

Name each molecular compound.
\begin{equation} \quad \text { a. }
\mathrm{CO} \quad \text { b. } \mathrm{NI}_{3} \quad \text { c. } \mathrm{SiCl}_{4} \quad \text { d. } \mathrm{N}_{4} \mathrm{Se}_{4}\end{equation}

Rikhil Makwana

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Problem 48

Name each molecular compound.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{SO}_{3} \quad \text { b. SO }_{2} \quad \text { c. BrF}_{5} \quad \text { d. NO }}\end{array}\end{equation}

James Irizarry

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Problem 49

Write the formula for each molecular compound.
\begin{equation}\begin{array}{ll}{\text { a. phosphorus trichloride }} & {\text { b. chlorine monoxide }} \\ {\text { c. disulfur tetrafluoride }} & {\text { d. phosphorus pentafluoride }}\end{array}\end{equation}

Rikhil Makwana

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Problem 50

Write the formula for each molecular compound.
\begin{equation}\begin{array}{ll}{\text { a. boron tribromide }} & {\text { b. dichlorine monoxide }} \\ {\text { c. xenon tetrafluoride }} & {\text { d. carbon tetrabromide }}\end{array}\end{equation}

James Irizarry

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Problem 51

Name each acid.
\begin{equation}\begin{array}{l}{\text { a. HI }(a q)} & {\text { b. } \mathrm{HNO}_{3}(a q) \quad \text { c. } \mathrm{H}_{2} \mathrm{CO}_{3}(a q)}\end{array}\end{equation}

Rikhil Makwana

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Problem 52

Name each acid.
\begin{equation}\begin{array}{l}{\text { a. HCl(aq) } \text { b. } \mathrm{HClO}_{2}(a q) \ \text { c. } \mathrm{H}_{2} \mathrm{SO}_{4}(a q)}\end{array}\end{equation}

James Irizarry

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Problem 53

Write the formula for each acid.
\begin{equation}\begin{array}{ll}{\text { a. hydrofluoric acid }} & {\text { b. hydrobromic acid }} \\ {\text { c. sulfurousacid }}\end{array}\end{equation}

Rikhil Makwana

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Problem 54

Write the formula for each acid.
\begin{equation}\begin{array}{ll}{\text { a. phosphoric acid }} & {\text { b. hydrobromic acid }} \\ {\text { c. chlorous acid }}\end{array}\end{equation}

James Irizarry

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Problem 55

Refer to the nomenclature flowchart (Figure 3.11) to name each compound.
\begin{equation} \quad \text { a. }\mathrm{SrCl}_{2} \quad \text { b. } \mathrm{SnO}_{2} \quad \text { c. }\mathrm{P}_{2} \mathrm{S}_{5} \quad \text { d. } \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}(a q)\end{equation}

Rikhil Makwana

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Problem 56

Refer to the nomenclature flowchart (Figure 3.11) to name each compound.
\begin{equation} \quad \text { a. }\mathrm{HNO}_{2}(a q) \quad \text { b. } \mathrm{B}_{2} \mathrm{Cl}_{2} \quad \text { c. }\mathrm{BaCl}_{2} \quad \text { d. } \mathrm{CrCl}_{3}
\end{equation}

James Irizarry

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Problem 57

Refer to the nomenclature flowchart (Figure 3.11) to name each compound.
\begin{equation} \quad \text { a. }\mathrm{KClO}_{3} \quad \text { b. } \mathrm{I}_{2} \mathrm{O}_{5} \quad \text { c. PbSO }_{4}\end{equation}

Rikhil Makwana

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Problem 58

Refer to the nomenclature flowchart (Figure 3.11) to name each compound.
\begin{equation} \quad \text { a. }\mathrm{XeO}_{3} \quad \text { b. KClO } \quad \text { c. } \cos \mathrm{O}_{4}\end{equation}

James Irizarry

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Problem 59

Calculate the formula mass for each compound.
\begin{equation} \quad \text { a. }\mathrm{NO}_{2} \quad \text { b. } \mathrm{C}_{4} \mathrm{H}_{10} \quad \text { c. } \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6} \quad \text { d. } \operatorname{Cr}\left(\mathrm{NO}_{3}\right)_{3}\end{equation}

KC

Kara Cecil

Numerade Educator

Problem 60

Calculate the formula mass for each compound.
\begin{equation} \quad \text { a. }\mathrm{MgBr}_{2} \quad \text { b. HNO }_{2} \quad \text { c. } \mathrm{CBr}_{4} \quad \text { d. } \operatorname{Ca}\left(\mathrm{NO}_{3}\right)_{2}\end{equation}

James Irizarry

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Problem 61

Calculate the number of moles in each sample.
\begin{equation}\begin{array}{llll}{\text { a. } 72.5 \mathrm{gCCl}_{4}} & {\text { b. } 12.4 \mathrm{g} \mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}} \\ {\text { c. } 25.2 \mathrm{kg} \mathrm{C}_{2} \mathrm{H}_{2}} & {\text { d. } 12.3 \mathrm{g} \text { dinitrogen monoxide }}\end{array}\end{equation}

WK

Waliul Islam Khan

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Problem 62

Calculate the mass of each sample.
\begin{equation}\begin{array}{l}{\text { a. } 15.7 \mathrm{mol} \mathrm{HNO}_{3}} \\ {\text { b. } 1.04 \times 10^{-3} \mathrm{mol} \mathrm{H}_{2} \mathrm{O}_{2}} \\ {\text { c. } 72.1 \mathrm{mmol} \mathrm{SO}_{2}} \\ {\text { d. } 1.23 \mathrm{mol} \text { xenon difluoride }}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 63

Determine the number of moles (of molecules or formula units) in each sample.
\begin{equation}\begin{array}{ll}{\text { a. } 25.5 \mathrm{gNO}_{2}} & {\text { b. } 1.25 \mathrm{kg} \mathrm{CO}_{2}} \\ {\text { c. } 38.2 \mathrm{gKNO}_{3}} & {\text { d. } 155.2 \mathrm{kg} \mathrm{Na}_{2} \mathrm{SO}_{4}}\end{array}\end{equation}

KC

Kara Cecil

Numerade Educator

Problem 64

Determine the number of moles (of molecules or formula units) in each sample.
\begin{equation}\begin{array}{ll}{\text { a. } 55.98 \mathrm{gCF}_{2} \mathrm{Cl}_{2}} & {\text { b. } 23.6 \mathrm{kg} \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2}} \\ {\text { c. } 0.1187 \mathrm{g} \mathrm{C}_{8} \mathrm{H}_{18}} & {\text { d. } 195 \mathrm{kg} \mathrm{CaO}}\end{array}\end{equation}

James Irizarry

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Problem 65

How many molecules are in each sample?
\begin{equation}\quad \text { a. } 6.5 \mathrm{gH}_{2} \mathrm{O} \quad \text { b. } 389 \mathrm{gCBr}_{4} \quad \text { c. } 22.1 \mathrm{g} \mathrm{O}_{2} \quad \text { d. } 19.3 \mathrm{g} \mathrm{C}_{8} \mathrm{H}_{10}\end{equation}

KC

Kara Cecil

Numerade Educator

Problem 66

How many molecules (or formula units) are in each sample?
\begin{equation}\begin{array}{ll}{\text { a. } 85.26 \mathrm{gCCl}_{4}} & {\text { b. } 55.93 \mathrm{kg} \mathrm{NaHCO}_{3}} \\ {\text { c. } 119.78 \mathrm{gC}_{4} \mathrm{H}_{10}} & {\text { d. } 4.59 \times 10^{5} \mathrm{g} \mathrm{Na}_{3} \mathrm{PO}_{4}}\end{array}\end{equation}

James Irizarry

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Problem 67

Calculate the mass (in g) of each sample.
\begin{equation}\begin{array}{l}{\text { a. } 5.94 \times 10^{20} \mathrm{SO}_{3} \text { molecules }} \\ {\text { b. } 2.8 \times 10^{22} \mathrm{H}_{2} \mathrm{O} \text { molecules }} \\ {\text { c. } 1 \text { glucose molecule }\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)}\end{array}\end{equation}

KC

Kara Cecil

Numerade Educator

Problem 68

Calculate the mass (in g) of each sample.
\begin{equation}\begin{array}{l}{\text { a. } 4.5 \times 10^{25} \mathrm{O}_{3} \text { molecules }} \\ {\text { b. } 9.85 \times 10^{19} \mathrm{CCl}_{2} \mathrm{F}_{2} \text { molecules }} \\ {\text { c. } 1 \text { water molecule }}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 69

A sugar crystal contains approximately $1.8 \times 10^{17}$ sucrose $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)$ molecules. What is its mass in mg?

KC

Kara Cecil

Numerade Educator

Problem 70

A salt crystal has a mass of 0.12 $\mathrm{mg} .$ How many NaCl formula units does it contain?

James Irizarry

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Problem 71

Calculate the mass percent composition of carbon in each carbon-containing compound.
\begin{equation} \quad \text { a. }\mathrm{CH}_{4} \quad \text { b. } \mathrm{C}_{2} \mathrm{H}_{6} \quad \text { c. } \mathrm{C}_{2} \mathrm{H}_{2} \quad \text { d. } \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}\end{equation}

KC

Kara Cecil

Numerade Educator

Problem 72

Calculate the mass percent composition of nitrogen in each nitrogen-containing compound.
\begin{equation}\quad \text { a. }\mathrm{N}_{2} \mathrm{O} \quad \text { b. } \mathrm{NO} \quad \text { c. } \mathrm{NO}_{2} \quad \text { d. HNO }_{3}\end{equation}

James Irizarry

Numerade Educator

Problem 73

Most fertilizers consist of nitrogen-containing compounds such as $\mathrm{NH}_{3}, \mathrm{CO}\left(\mathrm{NH}_{2}\right)_{2}, \mathrm{NH}_{4} \mathrm{NO}_{3},$ and $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{SO}_{4} .$ Plants use the nitrogen content in these compounds for protein synthesis. Calculate the mass percent composition of nitrogen in each of
the fertilizers listed. Which fertilizer has the highest nitrogen content?

Ronald Prasad

Numerade Educator

Problem 74

Iron in the earth is in the form of iron ore. Common ores include $\mathrm{Fe}_{2} \mathrm{O}_{3}$ (hematite), $\mathrm{Fe}_{3} \mathrm{O}_{4}$ (magnetite), and FeCO$_{3}$ (siderite). Calculate the mass percent composition of iron for each of these iron ores. Which ore has the highest iron content?

James Irizarry

Numerade Educator

Problem 75

Copper(II) fluoride contains 37.42$\% \mathrm{F}$ by mass. Calculate the mass of fluorine (in $\mathrm{g} )$ in 55.5 $\mathrm{g}$ of copper(II) fluoride.

Ronald Prasad

Numerade Educator

Problem 76

Silver chloride, often used in silver plating, contains 75.27$\%$ Ag by mass. Calculate the mass of silver chloride required to plate 155 mg of pure silver.

James Irizarry

Numerade Educator

Problem 77

The iodide ion is a dietary mineral essential to good nutrition. In countries where potassium iodide is added to salt, iodine deficiency (or goiter) has been almost completely eliminated. The recommended daily allowance (RDA) for iodine is 150$\mu \mathrm{g} / \mathrm{day}$. How much potassium iodide $(76.45 \% \mathrm{I})$ should you consume if you want to meet the RDA?

ER

Eli Riekeberg

Numerade Educator

Problem 78

The American Dental Association recommends that an adult female should consume 3.0 $\mathrm{mg}$ of fluoride $\left(\mathrm{F}^{-}\right)$per day to prevent tooth decay. If the fluoride is consumed in the form of sodium fluoride $(45.24 \% \mathrm{F}),$ what amount of sodium fluoride contains the recommended amount of fluoride?

James Irizarry

Numerade Educator

Problem 79

Write a ratio showing the relationship between the molar amounts of each element for each compound. (See Appendix IIA for color codes.)

Ronald Prasad

Numerade Educator

Problem 80

Write a ratio showing the relationship between the molar amounts of each element for each compound. (See Appendix IIA for color codes.)

James Irizarry

Numerade Educator

Problem 81

Determine the number of moles of hydrogen atoms in each sample.
\begin{equation}\begin{array}{ll}{\text { a. } 0.0885 \mathrm{mol} \mathrm{C}_{4} \mathrm{H}_{10}} & {\text { b. } 1.3 \mathrm{mol} \mathrm{CH}_{4}} \\ {\text { c. } 2.4 \mathrm{mol} \mathrm{C}_{6} \mathrm{H}_{12}} & {\text { d. } 1.87 \mathrm{mol} \mathrm{C}_{8} \mathrm{H}_{18}}\end{array}\end{equation}

Ronald Prasad

Numerade Educator

Problem 82

Determine the number of moles of oxygen atoms in each sample.
\begin{equation}
\begin{array}{ll}{\text { a. } 4.88 \mathrm{mol} \mathrm{H}_{2} \mathrm{O}_{2}} & {\text { b. } 2.15 \mathrm{mol} \mathrm{N}_{2} \mathrm{O}} \\ {\mathrm{c} .0 .0237 \mathrm{mol} \mathrm{H}_{2} \mathrm{CO}_{3}} & {\text { d. } 24.1 \mathrm{mol} \mathrm{CO}_{2}}\end{array}
\end{equation}

Angela Williamson

Angela Williamson

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Problem 83

Calculate mass (in grams) of sodium in 8.5 $\mathrm{g}$ of each sodium-containing food additive.
\begin{equation}\begin{array}{l}{\text { a. NaCl (table salt) }} \\ {\text { b. } \mathrm{Na}_{3} \mathrm{PO}_{4}(\text { sodium phosphate })} \\ {\text { c. } \mathrm{NaC}_{7} \mathrm{H}_{5} \mathrm{O}_{2} \text { (sodium benzoate) }} \\ {\text { d. } \mathrm{Na}_{2} \mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{7}(\text { sodium hydrogen citrate })}\end{array}\end{equation}

Ronald Prasad

Numerade Educator

Problem 84

Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).
\begin{equation}\quad \text { a. }\mathrm{CF}_{2} \mathrm{Cl}_{2} \quad \text { b. } \mathrm{CFCl}_{3} \quad \text { c. } \mathrm{C}_{2} \mathrm{F}_{3} \mathrm{Cl}_{3} \quad \text { d. } \mathrm{CF}_{3} \mathrm{Cl}\end{equation}

James Irizarry

Numerade Educator

Problem 85

How many fluorine atoms are present in 5.85 $\mathrm{g}$ of $\mathrm{C}_{2} \mathrm{F}_{4} ?$

Ronald Prasad

Numerade Educator

Problem 86

How many bromine atoms are present in 35.2 $\mathrm{g}$ of $\mathrm{CH}_{2} \mathrm{Br}_{2} ?$

James Irizarry

Numerade Educator

Problem 87

A chemist decomposes samples of several compounds; the masses of their constituent elements are listed. Calculate the empirical formula for each compound.
\begin{equation}
\begin{array}{l}{\text { a. } 1.651 \text { g Ag, } 0.1224 \mathrm{g} \mathrm{O}} \\ {\text { b. } 0.672 \mathrm{g} \mathrm{Co}, 0.569 \mathrm{g} \mathrm{As}, 0.486 \mathrm{gO}} \\ {\text { c. } 1.443 \mathrm{g} \mathrm{Se}, 5.841 \mathrm{g} \mathrm{Br}}\end{array}
\end{equation}

Ronald Prasad

Numerade Educator

Problem 88

A chemist decomposes samples of several compounds; the masses of their constituent elements are listed. Calculate the empirical formula for each compound.
\begin{equation}\begin{array}{l}{\text { a. } 1.245 \text { g } \mathrm{Ni}, 5.381 \mathrm{g} \mathrm{I}} \\ {\text { b. } 2.677 \mathrm{g} \mathrm{Ba}, 3.115 \mathrm{g} \mathrm{Br}} \\ {\text { c. } 2.128 \mathrm{g} \mathrm{Be}, 7.557 \mathrm{g} \mathrm{S}, 15.107 \mathrm{g} \mathrm{O}}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 89

Calculate the empirical formula for each stimulant based on its elemental mass percent composition.
\begin{equation}\begin{array}{l}{\text { a. nicotine (found in tobacco leaves): C } 74.03 \%, \mathrm{H} 8.70 \%,} \\ \quad {\text { N } 17.27 \%}\\ {\text { b. caffeine (found in coffee beans): } \mathrm{C} 49.48 \%, \mathrm{H} \text { 5.19\%, }} \\ \quad {\mathrm{N} 28.85 \%, \mathrm{O} 16.48 \%} \end{array}\end{equation}

MK

Michael Kelly

Numerade Educator

Problem 90

Calculate the empirical formula for each natural flavor based on its elemental mass percent composition.
\begin{equation}
\begin{array}{l}{\text { a. methyl butyrate (component of apple taste and smell): }} \\ \quad {\text { C } 58.80 \%, \mathrm{H} 9.87 \%, \mathrm{O} 31.33 \%}\\ {\text { b. vanillin (responsible for the taste and smell of vanilla): }} \\ \quad {\text { C } 63.15 \%, \text { H } 5.30 \%, \text { O } 31.55 \%}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 91

The elemental mass percent composition of ibuprofen (a nonsteroidal anti-inflammatory drug [NSAID]) is $75.69 \% \mathrm{C}, 8.80 \% \mathrm{H}$, and 15.51$\%$ O. Determine the empirical formula of ibuprofen.

Ronald Prasad

Numerade Educator

Problem 92

The elemental mass percent composition of ascorbic acid (vitamin $\mathrm{C} )$ is $40.99 \% \mathrm{C}, 4.58 \% \mathrm{H},$ and 54.50$\%$ o. Determine the empirical formula of ascorbic acid.

James Irizarry

Numerade Educator

Problem 93

A 0.77-mg sample of nitrogen reacts with chlorine to form $\mathrm{mg}$ of the chloride. Determine the empirical formula of nitrogen chloride.

Ronald Prasad

Numerade Educator

Problem 94

A 45.2 -mg sample of phosphorus reacts with selenium to form 131.6 $\mathrm{mg}$ of the selenide. Determine the empirical formula of phosphorus selenide.

James Irizarry

Numerade Educator

Problem 95

From the given empirical formula and molar mass, find the molecular formula of each compound.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{C}_{6} \mathrm{H}_{7} \mathrm{N}, 186.24 \mathrm{g} / \mathrm{mol}} \quad \quad \text { b. } \mathrm{C}_{2} \mathrm{HCl}, 181.44 \mathrm{g} / \mathrm{mol} \\ {\text { c. } \mathrm{C}_{5} \mathrm{H}_{10} \mathrm{NS}_{2}, 296.54 \mathrm{g} / \mathrm{mol}}\end{array}
\end{equation}

Ronald Prasad

Numerade Educator

Problem 96

From the given molar mass and empirical formula of several compounds, find the molecular formula of each compound.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{C}_{4} \mathrm{H}_{9}, 114.22 \mathrm{g} / \mathrm{mol}} \quad \text { b. } \mathrm{CCl}, 284.77 \mathrm{g} / \mathrm{mol} \\ {\text { c. } \mathrm{C}_{3} \mathrm{H}_{2} \mathrm{N}, 312.29 \mathrm{g} / \mathrm{mol}}\end{array}
\end{equation}

James Irizarry

Numerade Educator

Problem 97

Combustion analysis of a hydrocarbon produces 33.01 $\mathrm{g} \mathrm{CO}_{2}$ and 13.51 $\mathrm{g} \mathrm{H}_{2} \mathrm{O} .$ Calculate the empirical formula of the hydrocarbon.

Ronald Prasad

Numerade Educator

Problem 98

Combustion analysis of naphthalene, a hydrocarbon used in mothballs, produces 8.80 $\mathrm{g} \mathrm{CO}_{2}$ and 1.44 $\mathrm{g} \mathrm{H}_{2} \mathrm{O} .$ Calculate the empirical formula of naphthalene.

James Irizarry

Numerade Educator

Problem 99

The foul odor of rancid butter is due largely to butyric acid, a compound containing carbon, hydrogen, and oxygen. Combustion analysis of a $4.30-$ g sample of butyric acid produces 8.59 $\mathrm{g} \mathrm{CO}_{2}$ and 3.52 $\mathrm{g} \mathrm{H}_{2} \mathrm{O} .$ Determine the empirical formula of butyric acid.

Ronald Prasad

Numerade Educator

Problem 100

Tartaric acid is the white, powdery substance that coats tart candies such as Sour Patch Kids. Combustion analysis of a $12.01-g$ sample of tartaric acid-which contains only carbon, hydrogen, and oxygen-produces 14.08 $\mathrm{g} \mathrm{CO}_{2}$ and 4.32 $\mathrm{gH}_{2} \mathrm{O}$. Determine the empirical formula of tartaric acid.

James Irizarry

Numerade Educator

Problem 101

Sulfuric acid is a component of acid rain formed when gaseous sulfur dioxide pollutant reacts with gaseous oxygen and liquid water to form aqueous sulfuric acid. Write the balanced chemical equation this reaction. (Note: this is a simplified representation of this reaction.)

Rikhil Makwana

Numerade Educator

Problem 102

Nitric acid is a component of acid rain that forms when gaseous nitrogen dioxide pollutant reacts with gaseous oxygen and liquid water to form aqueous nitric acid. Write the balanced chemical equation for this reaction. (Note: this a simplified representation of this reaction.)

James Irizarry

Numerade Educator

Problem 103

In a popular classroom demonstration, solid sodium is added to liquid water and reacts to produce hydrogen gas and aqueous sodium hydroxide. Write the balanced chemical equation for this reaction.

Rikhil Makwana

Numerade Educator

Problem 104

When iron rusts, solid iron reacts with gaseous oxygen to form solid iron(III) oxide. Write the balanced chemical equation for this reaction.

Ronald Prasad

Numerade Educator

Problem 105

Write the balanced chemical equation for the fermentation of sucrose $\left(\mathrm{C}_{12} \mathrm{H}_{22} \mathrm{O}_{11}\right)$ by yeasts in which the aqueous sugar reacts with water to form aqueous ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ and carbon dioxide gas.

Rikhil Makwana

Numerade Educator

Problem 106

Write the balanced equation for the photosynthesis reaction in which gaseous carbon dioxide and liquid water react in the presence of chlorophyll to produce aqueous glucose $\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\right)$ and oxygen gas.

James Irizarry

Numerade Educator

Problem 107

Write the balanced chemical equation for each reaction.
\begin{equation}\begin{array}{l}{\text { a. Solid lead(II) sulfide reacts with aqueous hydrobromic }} \\ \quad {\text { acid to form solid lead(II) bromide and dihydrogen monosulfide }} \\ \quad {\text { gas. }}\\ {\text { b. Gaseous carbon monoxide reacts with hydrogen gas to form }} \\ \quad{\text { gaseous methane }\left(\mathrm{CH}_{4}\right) \text { and liquid water. }}\\ {\text { c. Aqueous hydrochloric acid reacts with solid manganese(IV) }} \\ \quad {\text { oxide to form aqueous manganese(II) chloride, liquid water, }} \\ \quad {\text { and chlorine gas. }} \\ {\text { d. Liquid pentane }\left(\mathrm{C}_{5} \mathrm{H}_{12}\right) \text { reacts with gaseous oxygen to form }} \\ \quad {\text { carbon dioxide and liquid water. }}\end{array}\end{equation}

Ronald Prasad

Numerade Educator

Problem 108

Write the balanced chemical equation for each reaction.
\begin{equation}\begin{array}{l}{\text { a. Solid copper reacts with solid sulfur to form solid copper(I) }} \\ \quad {\text { sulfide. }} \\ {\text { b. Solid iron(III) oxide reacts with hydrogen gas to form solid }} \\ \quad {\text { iron and liquid water. }}\\ {\text { c. Sulfur dioxide gas reacts with oxygen gas to form sulfur trioxide }} \\ \quad {\text { gas. }} \\ {\text { d. Gaseous ammonia (NH_ ) reacts with gaseous oxygen to form }} \\ \quad {\text { gaseous nitrogen monoxide and gaseous water. }}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 109

Write the balanced chemical equation for the reaction of aqueous sodium carbonate with aqueous copper(II) chloride to form solid copper(II) carbonate and aqueous sodium chloride.

Rikhil Makwana

Numerade Educator

Problem 110

Write the balanced chemical equation for the reaction of aqueous potassium hydroxide with aqueous iron(III) chloride to form solid iron(II) hydroxide and aqueous potassium chloride.

James Irizarry

Numerade Educator

Problem 111

Balance each chemical equation.
\begin{equation}
\begin{array}{l}{\text { a. } \mathrm{CO}_{2}(g)+\mathrm{CaSiO}_{3}(s)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow} \mathrm{SiO}_{2}(s)+\mathrm{Ca}\left(\mathrm{HCO}_{3}\right)_{2}(a q) \\ {\text { b. } \mathrm{Co}\left(\mathrm{NO}_{3}\right)_{3}(a q)+\left(\mathrm{NH}_{4}\right) \mathrm{S}(a q) \longrightarrow \mathrm{Co}_{2} \mathrm{S}_{3}(s)+\mathrm{NH}_{4} \mathrm{NO}_{3}(a q)} \\ {\text { c. } \mathrm{Cu}_{2} \mathrm{O}(s)+\mathrm{Cl}(s) \longrightarrow \mathrm{Cu}(s)+\mathrm{CO}(g)} \\ {\text { d. } \mathrm{H}_{2}(g)+\mathrm{Cl}_{2}(g) \longrightarrow \mathrm{HCl}(g)}\end{array}\end{equation}

Ronald Prasad

Numerade Educator

Problem 112

Balance each chemical equation.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{Na}_{2} \mathrm{S}(a q)+\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(a q) \longrightarrow \mathrm{NaNO}_{3}(a q)+\mathrm{CuS}(s)} \\ {\text { b. } \mathrm{N}_{2} \mathrm{H}_{4}(l) \longrightarrow \mathrm{NH}_{3}(g)+\mathrm{N}_{2}(g)} \\ {\text { c. } \mathrm{HCl}(a q)+\mathrm{O}_{2}(g) \longrightarrow \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{Cl}_{2}(g)} \\ {\text { d. } \mathrm{FeS}(s)+\mathrm{HCl}(a q) \rightarrow \mathrm{FeCl}_{2}(a q)+\mathrm{H}_{2} \mathrm{S}(g)}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 113

Classify each compound as organic or inorganic.
\begin{equation}
\begin{array}{l}{\text { a. } \mathrm{CaCO}_{3} \quad \text { b. } \mathrm{C}_{4} \mathrm{H}_{8} \quad \text { c. } \mathrm{C}_{4} \mathrm{H}_{6} \mathrm{O}_{6} \quad \text { d. LiF }}\end{array}
\end{equation}

Rikhil Makwana

Numerade Educator

Problem 114

Classify each compound as organic or inorganic.
\begin{equation}\begin{array}{l} {\text { a. } \mathrm{C}_{8} \mathrm{H}_{18} \quad \text { b. } \mathrm{CH}_{3} \mathrm{NH}_{2} \quad \text { c. } \mathrm{CaO} \quad \text { d. FeCO }_{3}}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 115

Classify each hydrocarbon as an alkane, alkene, or alkyne.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{H}_{2} \mathrm{C}=\mathrm{CH}-\mathrm{CH}_{3}} \\ {\text { b. } \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{CH}_{3}} \\ {\text { c. } \mathrm{HC}=\mathrm{C}-\mathrm{CH}_{3}} \\ {\text { d. } \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}_{3}}\end{array}\end{equation}

Rikhil Makwana

Numerade Educator

Problem 116

Classify each hydrocarbon as an alkane, alkene, or alkyne.
\begin{equation}\begin{array}{l}{\text { a. } \mathrm{HC}=\mathrm{CH}}\end{array} \quad \quad \text { b. } \mathrm{H}_{3} \mathrm{C}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}_{3}
\end{equation}
\begin{equation}
\begin{array}{ll} \\ \text { c. } & {\mathrm{CH}_{3}} & {\text { d. } \mathrm{H}_{3} \mathrm{C}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_{3}} \\ {\mathrm{H}_{3} \mathrm{C}-} & {\mathrm{CH}-\mathrm{CH}_{3}}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 117

Write the formula based on the name, or the name based on the formula, for each hydrocarbon.
\begin{equation}\begin{array}{ll}{\text { a. propane }} & {\text { b. } C \mathrm{H}_{3} \mathrm{CH}_{2} \mathrm{CH}_{3}} \\ {\text { c. octane }} & {\text { d. } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}}\end{array}\end{equation}

Rikhil Makwana

Numerade Educator

Problem 118

Write the formula based on the name, or the name based on the formula, for each hydrocarbon.
\begin{equation}\begin{array}{ll}{\text { a. } \mathrm{CH}_{3} \mathrm{CH}_{3}} & {\text { b. pentane }} \\ {\text { c. } \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2}} & {\text { d. heptane }}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 119

Classify each organic compound as a hydrocarbon or a functionalized hydrocarbon. For functionalized hydrocarbons, identify the compound's family.

Ronald Prasad

Numerade Educator

Problem 120

Classify each organic compound as a hydrocarbon or a functionalized hydrocarbon. For functionalized hydrocarbons, identify the compound's family.

James Irizarry

Numerade Educator

Problem 121

How many molecules of ethanol $\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)$ (the alcohol in alcoholic beverages) are present in 145 $\mathrm{mL}$ of ethanol? The density of ethanol is 0.789 $\mathrm{g} / \mathrm{cm}^{3} .$

Ronald Prasad

Numerade Educator

Problem 122

A drop of water has a volume of approximately 0.05 $\mathrm{mL}$ . How many water molecules does it contain? The density of water is 1.0 $\mathrm{g} / \mathrm{cm}^{3} .$

James Irizarry

Numerade Educator

Problem 123

Determine the chemical formula of each compound and then use it to calculate the mass percent composition of each constituent element.
\begin{equation}\begin{array}{ll}{\text { a. potassium chromate }} & {\text { b. lead(II) phosphate }} \\ {\text { c. sulfurous acid }} & {\text { d. cobalt(II) bromide }}\end{array}\end{equation}

Ronald Prasad

Numerade Educator

Problem 124

Determine the chemical formula of each compound and then use it to calculate the mass percent composition of each constituent element.
\begin{equation}
\begin{array}{l}{\text { a. perchloric acid }} \\ {\text { b. phosphorus pentachloride }} \\ {\text { c. nitrogen triiodide }} \\ {\text { d. carbon dioxide }}\end{array}
\end{equation}

James Irizarry

Numerade Educator

Problem 125

A Freon leak in the air-conditioning system of an old car releases 25 g of $\mathrm{CF}_{2} \mathrm{Cl}_{2}$ per month. What mass of chlorine does this car emit into the atmosphere each year?

Ronald Prasad

Numerade Educator

Problem 126

A Freon leak in the air-conditioning system of a large building releases 12 kg of $\mathrm{CHF}_{2} \mathrm{Cl}$ per month. If the leak is allowed to continue, how many kilograms of Cl will be emitted into the atmosphere each year?

James Irizarry

Numerade Educator

Problem 127

A metal (M) forms a compound with the formula $\mathrm{MCl}_{3}.$ If the compound contains 65.57$\%$ Cl by mass, what is the identity of the metal?

Ronald Prasad

Numerade Educator

Problem 128

A metal (M) forms an oxide with the formula $\mathrm{M}_{2} \mathrm{O}$ . If the oxide contains 16.99$\% \mathrm{O}$ by mass, what is the identity of the metal?

James Irizarry

Numerade Educator

Problem 129

Estradiol is a female sexual hormone that is responsible for the maturation and maintenance of the female reproductive system. Elemental analysis of estradiol gives the following mass percent composition: $\mathrm{C} 79.37 \%, \mathrm{H} 8.88 \%, \mathrm{O} 11.75 \% .$ The molar mass of estradiol is 272.37 $\mathrm{g} / \mathrm{mol} .$ Find the molecular formula of estradiol.

Ronald Prasad

Numerade Educator

Problem 130

Fructose is a common sugar found in fruit. Elemental analysis of fructose gives the following mass percent composition: C $40.00 \%, \mathrm{H} 6.72 \%, \mathrm{O} 53.28 \% .$ The molar mass of fructose is 180.16 $\mathrm{g} / \mathrm{mol} .$ Find the molecular formula of fructose.

James Irizarry

Numerade Educator

Problem 131

Combustion analysis of a $13.42-\mathrm{g}$ sample of equilin (which contains only carbon, hydrogen, and oxygen) produces 39.61 $\mathrm{g} \mathrm{CO}_{2}$ and 9.01 $\mathrm{g} \mathrm{H}_{2} \mathrm{O} .$ The molar mass of equilin is 268.34 $\mathrm{g} / \mathrm{mol}$ Find its molecular formula.

Ronald Prasad

Numerade Educator

Problem 132

Estrone, which contains only carbon, hydrogen, and oxygen, is a female sexual hormone in the urine of pregnant women. Combustion analysis of a $1.893-$ sample of estrone produces 5.545 $\mathrm{g}$ of $\mathrm{CO}_{2}$ and 1.388 $\mathrm{g} \mathrm{H}_{2} \mathrm{O} .$ The molar mass of estrone is 270.36 $\mathrm{g} / \mathrm{mol} .$ Find its molecular formula.

James Irizarry

Numerade Educator

Problem 133

Epsom salts is a hydrated ionic compound with the following formula: $\mathrm{MgSO}_{4} \cdot x \mathrm{H}_{2} \mathrm{O} . \mathrm{A} 4.93-\mathrm{g}$ sample of Epsom salts is heated to drive off the water of hydration. The mass of the sample after complete dehydration is 2.41 $\mathrm{g}$ . Find the number of waters of hydration $(x)$ in Epsom salts.

Ronald Prasad

Numerade Educator

Problem 134

A hydrate of copper(II) chloride has the following formula: $\mathrm{CuCl}_{2} \cdot x \mathrm{H}_{2} \mathrm{O}$ . The water in a $3.41-\mathrm{g}$ sample of the hydrate is driven off by heating. The remaining sample has a mass of 2.69 $\mathrm{g}$ .Find the number of waters of hydration $(x)$ in the hydrate.

James Irizarry

Numerade Educator

Problem 135

A compound of molar mass 177 $\mathrm{g} / \mathrm{mol}$ contains only carbon, hydrogen, bromine, and oxygen. Analysis reveals that the compound contains eight times as much carbon as hydrogen by mass. Find the molecular formula.

MT

Marshall Tomat

Numerade Educator

Problem 136

Researchers obtained the following data from experiments to find the molecular formula of benzocaine, a local anesthetic, which contains only carbon, hydrogen, nitrogen, and oxygen. Complete combustion of a 3.54 sample of benzocaine with excess $\mathrm{O}_{2}$ forms 8.49 g of $\mathrm{CO}_{2}$ and 2.14 $\mathrm{g} \mathrm{H}_{2} \mathrm{O}$ . Another $2.35 \mathrm{g}$ sample contains 0.199 $\mathrm{g}$ of $\mathrm{N} .$ The molar mass of benzocaine is 165 $\mathrm{g} / \mathrm{mol} .$ Find the molar formula of benzocaine.

James Irizarry

Numerade Educator

Problem 137

Find the total number of atoms in a sample of cocaine hydro-chloride, $\mathrm{C}_{17} \mathrm{H}_{22} \mathrm{ClNO}_{4},$ of mass 23.5 $\mathrm{mg} .$

Ronald Prasad

Numerade Educator

Problem 138

Vanadium forms four different oxides in which the percent by mass of vanadium is, respectively, (a) $76 \%,$ (b) $68 \%,(\mathrm{c}) 61 \%,$ and (d) 56$\% .$ Determine the formula and the name of each oxide.

James Irizarry

Numerade Educator

Problem 139

The chloride of an unknown metal is believed to have the formula $\mathrm{MCl}_{3} . \mathrm{A}$ 2.395-g sample of the compound contains $3.606 \times 10^{-2} \mathrm{mol} \mathrm{Cl} .$ Find the atomic mass of $\mathrm{M} .$

Ronald Prasad

Numerade Educator

Problem 140

Write the structural formulas of three different compounds that each have the molecular formula $\mathrm{C}_{5} \mathrm{H}_{12}.$

James Irizarry

Numerade Educator

Problem 141

A chromium-containing compound has the formula $\mathrm{Fe}_{x} \mathrm{Cr}_{y} \mathrm{O}_{4}$ and is 28.59$\%$ oxygen by mass. Find $x$ and $y .$

Ronald Prasad

Numerade Educator

Problem 142

A phosphorus compound that contains 34.00$\%$ phosphorus by mass has the formula $\mathrm{X}_{3} \mathrm{P}_{2}$ . Identify the element $\mathrm{X}$ .

James Irizarry

Numerade Educator

Problem 143

A particular brand of beef jerky contains 0.0552$\%$ sodium nitrite by mass and is sold in an $8.00-$ oz bag. What mass of sodium does the sodium nitrite contribute to the sodium content of the bag of beef jerky?

Ronald Prasad

Numerade Educator

Problem 144

Phosphorus is obtained primarily from ores containing calcium phosphate. If a particular ore contains 57.8$\%$ calcium phosphate, what minimum mass of the ore must be processed to obtain 1.00 kg of phosphorus?

James Irizarry

Numerade Educator

Problem 145

A mixture of $\mathrm{NaCl}$ and $\mathrm{NaBr}$ has a mass of 2.00 $\mathrm{g}$ and contains 0.75 $\mathrm{g}$ of Na. What is the mass of NaBr in the mixture?

Ronald Prasad

Numerade Educator

Problem 146

Three pure compounds form when 1.00 -g samples of element $X$ combine with, respectively, $0.472 \mathrm{g}, 0.630 \mathrm{g},$ and 0.789 $\mathrm{g}$ of element Z. The first compound has the formula $\mathrm{X}_{2} \mathrm{Z}_{3}$ . Find the empirical formulas of the other two compounds.

James Irizarry

Numerade Educator

Problem 147

A mixture of $\mathrm{CaCO}_{3}$ and $\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3}$ is 61.9$\% \mathrm{CO}_{3}$ by mass. Find the mass percent of $\mathrm{CaCO}_{3}$ in the mixture.

Ronald Prasad

Numerade Educator

Problem 148

A mixture of 50.0 $\mathrm{g}$ of S and $1.00 \times 10^{2} \mathrm{g}$ of $\mathrm{Cl}_{2}$ reacts completely to form $\mathrm{S}_{2} \mathrm{Cl}_{2}$ and $\mathrm{SCl}_{2}$ . Find the mass of $\mathrm{S}_{2} \mathrm{Cl}_{2}$ formed.

James Irizarry

Numerade Educator

Problem 149

Because of increasing evidence of damage to the ozone layer, chlorofluorocarbon (CFC) production was banned in $1996 .$ However, many older cars still have air conditioners that use $\mathrm{CFC}-12\left(\mathrm{CF}_{2} \mathrm{Cl}_{2}\right) .$ These air conditioners are recharged from stockpiled supplies of CFC-12. Suppose that 100 million auto-mobiles each contain 1.1 $\mathrm{kg}$ of $\mathrm{CFC}-12$ and leak 25$\%$ of their $\mathrm{CFC}-12$ into the atmosphere per year. How much chlorine, in $\mathrm{kg},$ is added to the atmosphere each year due to to these air conditioners? (Assume two significant figures in your calculations.)

Ronald Prasad

Numerade Educator

Problem 150

A particular coal contains 2.55$\%$ sulfur by mass. When the coal is burned, it produces $S O_{2}$ emissions, which combine with rain-water to produce sulfuric acid. Use the formula of sulfuric acid to calculate the mass percent of $S$ in sulfuric acid. Then determine how much sulfuric acid (in metric tons) is produced by the combustion of 1.0 metric ton of this coal. (A metric ton is 1000 $\mathrm{kg.}$ .

James Irizarry

Numerade Educator

Problem 151

Lead is found in Earth's crust as several different lead ores. Suppose a certain rock is 38.0$\%$ Pbs (galena), 25.0$\%$ PbCO $_{3}$ (cerussite), and 17.4$\%$ PbSO $_{4}$ (anglesite). The remainder of the rock is composed of substances containing no lead. How much of this rock (in kg must be processed to obtain 5.0 metric tons of lead? (A metric ton is 1000 $\mathrm{kg.}$ .

Ronald Prasad

Numerade Educator

Problem 152

A 2.52 -g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur is burned in excess oxygen to yield 4.23 g of $\mathrm{CO}_{2}$ and 1.01 $\mathrm{g}$ of $\mathrm{H}_{2} \mathrm{O}$ . Another sample of the same compound, of mass 4.14 g, yields 2.11 g of $\mathrm{SO}_{3} .$ A third sample, of mass $5.66 \mathrm{g},$ yields 2.27 $\mathrm{g}$ of HNO $_{3} .$ Calculate the empirical formula of the compound.

James Irizarry

Numerade Educator

Problem 153

A compound of molar mass 229 $\mathrm{g} / \mathrm{mol}$ contains only carbon, hydrogen, iodine, and sulfur. Analysis shows that a sample of the compound contains six times as much carbon as hydrogen, by mass. Calculate the molecular formula of the compound.

Ronald Prasad

Numerade Educator

Problem 154

The elements $\mathrm{X}$ and $\mathrm{Y}$ form a compound that is 40$\% \mathrm{X}$ and 60$\%$ $\mathrm{Y}$ by mass. The atomic mass of $\mathrm{X}$ is twice that of Y. What is the empirical formula of the compound?

James Irizarry

Numerade Educator

Problem 155

A compound of $\mathrm{X}$ and $\mathrm{Y}$ is $\frac{1}{3} \mathrm{X}$ by mass. The atomic mass of element $\mathrm{X}$ is $\frac{1}{3}$ the atomic mass of element $\mathrm{Y}$ . Find the empirical formula of the compound.

Ronald Prasad

Numerade Educator

Problem 156

A mixture of carbon and sulfur has a mass of 9.0 $\mathrm{g} .$ Complete combustion with excess $\mathrm{O}_{2}$ gives 23.3 $\mathrm{g}$ of a mixture of $\mathrm{CO}_{2}$ and $\mathrm{SO}_{2} .$ Find the mass of sulfur in the original mixture.

James Irizarry

Numerade Educator

Problem 157

When molecules are represented by molecular models, what does each sphere represent? How big is the nucleus of an atom in comparison to the sphere used to represent an atom in a molecular model?

Ronald Prasad

Numerade Educator

Problem 158

Without doing any calculations, determine which element in each compound has the highest mass percent composition.
\begin{equation}\begin{array}{ll}{\text { a. } \mathrm{CO}} & {\text { b. } \mathrm{N}_{2} \mathrm{O}} \\ {\text { c. } \mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}} & {\mathrm{d} . \mathrm{NH}_{3}}\end{array}\end{equation}

James Irizarry

Numerade Educator

Problem 159

Explain the problem with the following statement and correct it: "The chemical formula for ammonia $\left(\mathrm{NH}_{3}\right)$ indicates that ammonia contains three grams of hydrogen for each gram of nitrogen."

Ronald Prasad

Numerade Educator

Problem 160

Explain the problem with the following statement and correct it. "When a chemical equation is balanced, the number of molecules of each type on both sides of the equation is equal."

James Irizarry

Numerade Educator

Problem 161

Without doing any calculations, arrange the elements in $\mathrm{H}_{2} \mathrm{SO}_{4}$ in order of decreasing mass percent composition.

Ronald Prasad

Numerade Educator

Problem 162

Element $\mathrm{A}$ is an atomic element, and element $\mathrm{B}$ is a diatomic molecular element. Using circles to represent atoms of $\mathrm{A}$ and squares to represent atoms of $\mathrm{B},$ draw molecular-level views of each element.

James Irizarry

Numerade Educator

Problem 163

With group members playing the roles of nuclei and electrons, demonstrate the formation of an ionic bond between Na and Cl. Demonstrate the formation of the covalent bonds in $\mathrm{H}_{2} \mathrm{O}$.

Ronald Prasad

Numerade Educator

Problem 164

Create a flowchart with a series of simple questions that can be used to determine whether a chemical formula is that of an atomic element, a molecular element, a molecular compound, or an ionic compound. Use your flowchart to identify the correct category for $\mathrm{P}_{4}, \mathrm{KCl}, \mathrm{CH}_{4}, \mathrm{Ne},$ and $\mathrm{NH}_{4} \mathrm{NO}_{3}$.

James Irizarry

Numerade Educator

Problem 165

Have each member of your group list one similarity or difference between the naming conventions for ionic and molecular compounds.

Ronald Prasad

Numerade Educator

Problem 166

A compound isolated from the rind of lemons is found to be 88.14$\%$ carbon and 11.86$\%$ hydrogen by mass. How many grams of $C$ and $H$ are there in a $100.0-g$ sample of this substance? How many moles of $C$ and $H ?$ What is the empirical formula? The molar mass is determined to be 136.26 $\mathrm{g} / \mathrm{mol}$ . What is the molecular formula? Which step of the process just described does your group understand the least? Which step will be hardest for the members of your group to remember?

James Irizarry

Numerade Educator

Problem 167

Octane $\left(\mathrm{C}_{8} \mathrm{H}_{18}\right),$ a component of gasoline, reacts with oxygen to form carbon dioxide and water. Write the balanced chemical reaction for this process by passing a single piece of paper around your group, having each group member complete the next logical step. As you each complete your step, explain your reasoning to the group.

Ronald Prasad

Numerade Educator

Problem 168

since the 1800 s, the concentration of carbon dioxide in Earth's atmosphere has been increasing (Figure a $\mathbf{\nabla}$ ). The scientific consensus is that the increase in $\mathrm{CO}_{2}$ is due to fossil fuel combustion.
\begin{equation}
\begin{array}{l}{\text { Use the information provided in the figure to answer the }} \\ {\text { following questions (Note that } 1 \text { ppmv }=1 \text { gas volume/ } 1 \times} \\ {10^{6} \text { air volumes }=1 \mu \mathrm{L} \text { gas } / 1 \mathrm{L} \text { air): }}\end{array}
\end{equation}
\begin{equation}
\begin{array}{l}{\text { a. Globally, in } 2010 \text { and } 2012, \text { respectively, there were about }} \\ \quad {9.20 \text { billion metric tons and } 9.60 \text { billion metric tons of }} \\ \quad {\text { carbon in Earth's atmosphere. }}\\ \quad \quad {\text { i. Determine the increase in carbon in the atmosphere in }} \\ \quad \quad \quad {\text { units of metric tons between } 2010 \text { and } 2012 .} \\ \quad \quad {\text { ii. Determine the increase of carbon dioxide in the atmosphere }} \\ \quad \quad \quad {\text { in units of metric tons between } 2010 \text { and } 2012 .}\\ {\text { b. Figure a lists the concentration of } \mathrm{CO}_{2} \text { in air in terms of }} \\ \quad {\text { parts per million by volume (ppmv). }} \\ \quad \quad {\text { i. Compare the volume (in mL) of } \mathrm{CO}_{2} \text { in } 1.00 \mathrm{m}^{3}} \\ \quad \quad \quad {\text { of air in } 1880 \text { to the volume }(\mathrm{in} \mathrm{mL}) \text { of } \mathrm{CO}_{2} \text { in }} \\ \quad \quad \quad {1.00 \mathrm{m}^{3} \text { of air in } 2014 .} \\ \quad \quad {\text { ii. Determine the increase in volume (in mL) of } \mathrm{CO}_{2} \text { in }} \\ \quad \quad \quad {1.00 \mathrm{m}^{3} \text { of air between } 1880 \text { and } 2014 .} \\ \quad \quad {\text { iii. What is the percent increase of } \mathrm{CO}_{2} \text { in }1.00 \mathrm{m}^{3} \text { of air }} \\ \quad \quad \quad {\text { between } 1880 \text { and } 2014 ?} \\ \quad \quad {\text { iv. Assuming that the total volume of air in the atmosphere }} \\ \quad \quad \quad {\text { around Earth is } 5.1 \times 10^{9} \mathrm{km}^{3} \text { and that the concentration }} \\ \quad \quad \quad {\text { of } \mathrm{CO}_{2} \text { is uniform throughout the atmosphere, }} \\ \quad \quad \quad {\text { estimate the volume of } \mathrm{CO}_{2} \text { in the atmosphere in } 2014} \\ \quad \quad \quad {\text { in units of } \mathrm{km}^{3} \text { . }}\\ {\text { c. Based on the information in Figure a, determine the }} \\ \quad {\text { average yearly increase in the concentration of } \mathrm{CO}_{2} \text { in }} \\ \quad {\text { the atmosphere for the period } 1960 \text { to } 2014 . \text { Estimate the }} \\ \quad {\text { concentration of } \mathrm{CO}_{2} \text { in the atmosphere, in units of ppmv, }} \\ \quad {\operatorname{in} 2030 .} \end{array}
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James Irizarry

Numerade Educator