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Chemistry

Raymond Chang, Jason Overby

Chapter 1

Chemistry: The Study of Change - all with Video Answers

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Chapter Questions

02:06

Problem 1

Explain what is meant by the scientific method.

Nicholas Mogoi
Nicholas Mogoi
Numerade Educator
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Problem 2

What is the difterence between qualitative data and filantitative data?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:11

Problem 3

Classify the following as qualitative or quantitative statements, giving your reasons. (a) The sun is approximately 93 million miles from Earth.
(b) Leonardo da Vinci was a better painter than Michelangelo. (c) Ice is less dense than water.
(d) Butter tastes better than margarine. (e) A stitch in time saves nine.

Ted Gray
Ted Gray
Numerade Educator
02:20

Problem 4

Classify each of the following statements as a hypothesis, a law, or a theory. (a) Beethoven's contribution to music would have been much greater if he had married. (b) An autumn leaf gravitates toward the ground because there is an attractive force between the leaf and Earth. (c) All matter is composed of very small particles called atoms.

David Collins
David Collins
Numerade Educator
01:59

Problem 5

Give an example for each of the following terms:
(a) matter. (b) substance (c) mixture.

Daniel Lai
Daniel Lai
Numerade Educator
00:41

Problem 6

Give an example of a homogeneous mixture and an example of a heterogeneous mixture.

David Collins
David Collins
Numerade Educator
01:41

Problem 7

Give an example of an element and a compound. How do elements and compounds differ?

Daniel Lai
Daniel Lai
Numerade Educator
00:05

Problem 8

What is the number of known elements?

Himanshu Garg
Himanshu Garg
Numerade Educator
02:42

Problem 9

Give the names of the elements represented by the chemical symbols $\mathrm{Li}, \mathrm{F}, \mathrm{P}, \mathrm{Cu}, \mathrm{As}, \mathrm{Zn}, \mathrm{Cl}, \mathrm{Pt}, \mathrm{Mg},$ $\mathrm{U}, \mathrm{Al}, \mathrm{Si},$ Ne. (See Table 1.1 and the list of The Elements with Their Symbols and Atomic Masses.)

Ted Gray
Ted Gray
Numerade Educator
02:55

Problem 10

Give the chemical symbols for the following elements: (a) cesium, (b) germanium, (c) gallium,
(d) strontium, (e) uranium, (f) selenium, (g) neon,
(h) cadmium. (See Table 1.1 and the inside front cover.)

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
02:59

Problem 11

Classify each of the following substances as an element or a compound:
(a) hydrogen, (b) water,
(c) gold, (d) sugar.

Daniel Lai
Daniel Lai
Numerade Educator
02:00

Problem 12

Classify each of the following as an element, a compound, a homogeneous mixture, or a heterogeneous mixture: (a) water from a well, (b) argon gas, (c) sucrose, (d) a bottle of red wine, (e) chicken noodle soup, (f) blood flowing in a capillary,
(g) ozone.

David Collins
David Collins
Numerade Educator
01:16

Problem 13

Identify each of the diagrams shown here as gas, liquid, or solid.
a.
b.
c.

Nicole Krahulik
Nicole Krahulik
Numerade Educator
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Problem 14

Explain how the distances between particles typically change with different states of matter.

Syon Schlecht
Syon Schlecht
Numerade Educator
03:02

Problem 15

Using examples, explain the difference between a physical property and a chemical property.

Daniel Lai
Daniel Lai
Numerade Educator
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Problem 16

How does an intensive property differ from an extensive property? Which of the following properties are intensive and which are extensive?
(a) length,
(b) volume, (c) temperature, (d) mass.

Ronald Prasad
Ronald Prasad
Numerade Educator
03:03

Problem 17

Do the following statements describe chemical or physical properties? (a) Oxygen gas supports combustion. (b) Fertilizers help to increase agricultural production. (c) Water boils below $100^{\circ} \mathrm{C}$ on top of $\mathrm{a}$ mountain. (d) Lead is more dense than aluminum.
(e) Uranium is a radioactive element.

Ted Gray
Ted Gray
Numerade Educator
01:13

Problem 18

Does each of the following describe a physical change or a chemical change? (a) The helium gas inside a balloon tends to leak out after a few hours.
(b) A flashlight beam slowly gets dimmer and finally goes out. (c) Frozen orange juice is reconstituted by adding water to it. (d) The growth of plants depends on the sun's energy in a process called photosynthesis. (e) A spoonful of table salt dissolves in a bowl of soup.

David Collins
David Collins
Numerade Educator
03:00

Problem 19

Name the SI base units that are important in chemistry. Give the SI units for expressing the following:
(a) length, (b) volume, (c) mass, (d) time, (e) energy, (f) temperature.

Daniel Lai
Daniel Lai
Numerade Educator
01:22

Problem 20

Write the numbers represented by the following prefixes: (a) mega-,
(b) kilo-
(c) deci-,
(d) centi-,
(e) milli-, (f) micro-
(g) nano-
(h) pico-

Himanshu Garg
Himanshu Garg
Numerade Educator
01:47

Problem 21

What units do chemists normally use for density of liquids and solids? For gas density? Explain the differences.

Daniel Lai
Daniel Lai
Numerade Educator
00:46

Problem 22

Describe the three temperature scales used in the laboratory and in everyday life: the Fahrenheit scale, the Celsius scale, and the Kelvin scale.

David Collins
David Collins
Numerade Educator
00:34

Problem 23

Bromine is a reddish-brown liquid. Calculate its density (in $g / \mathrm{mL}$ ) if $586 \mathrm{~g}$ of the substance occupies $188 \mathrm{~mL}$

Himanshu Garg
Himanshu Garg
Numerade Educator
00:32

Problem 24

The density of methanol, a colorless organic liquid used as solvent, is $0.7918 \mathrm{~g} / \mathrm{mL}$. Calculate the mass of $89.9 \mathrm{~mL}$ of the liquid.

David Collins
David Collins
Numerade Educator
04:51

Problem 25

Convert the following temperatures to degrees Celsius or Fahrenheit: (a) $95^{\circ} \mathrm{F}$, the temperature on a hot summer day; (b) $12^{\circ} \mathrm{F},$ the temperature on a cold winter day; (c) a $102^{\circ} \mathrm{F}$ fever; (d) a furnace operating at $1852^{\circ} \mathrm{F} ;$ (e) $-273.15^{\circ} \mathrm{C}$ (theoretically the lowest attainable temperature).

Daniel Lai
Daniel Lai
Numerade Educator
01:14

Problem 26

(a) Normally the human body can endure a temperature of $105^{\circ} \mathrm{F}$ for only short periods of time without permanent damage to the brain and other vital organs. What is this temperature in degrees Celsius?
(b) Ethylene glycol is a liquid organic compound that is used as an antifreeze in car radiators. It freezes at $-11.5^{\circ} \mathrm{C}$. Calculate its freezing temperature in degrees Fahrenheit. (c) The temperature on the surface of the sun is about $6300^{\circ} \mathrm{C}$. What is this temperature in degrees Fahrenheit? (d) The ignition temperature of paper is $451^{\circ} \mathrm{F}$. What is the temperature in degrees Celsius?

David Collins
David Collins
Numerade Educator
02:39

Problem 27

Convert the following temperatures to kelvin:
(a) $113^{\circ} \mathrm{C}$, the melting point of sulfur, (b) $37^{\circ} \mathrm{C}$, the normal body temperature,
(c) $357^{\circ} \mathrm{C},$ the boiling point of mercury.

Daniel Lai
Daniel Lai
Numerade Educator
01:00

Problem 28

Convert the following temperatures to degrees Celsius: (a) $77 \mathrm{~K}$, the boiling point of liguid nitrogen, (b) $4.2 \mathrm{~K},$ the boiling point of liquid helium,
(c) $601 \mathrm{~K},$ the melting point of lead.

Ted Gray
Ted Gray
Numerade Educator
01:44

Problem 29

What is the advantage of using scientific notation over decimal notation?

Daniel Lai
Daniel Lai
Numerade Educator
00:35

Problem 30

Define significant figure. Discuss the importance of using the proper number of significant figures in measurements and calculations.

Himanshu Garg
Himanshu Garg
Numerade Educator
03:39

Problem 31

Express the following numbers in scientific notation:
(a) 0.000000027 ,
(b) 356
(c) 47,764
(d) 0.096 .

Daniel Lai
Daniel Lai
Numerade Educator
01:43

Problem 32

Express the wing numbers as decimals:
(a) $1.52 \times 10^{-2},$ (b) $7.78 \times 10^{-8}$

Ted Gray
Ted Gray
Numerade Educator
07:58

Problem 33

Express the answers to the following calculations in scientific notation:
(a) $145.75+\left(2.3 \times 10^{-1}\right)$
(b) $79,500 \div\left(2.5 \times 10^{2}\right)$
(c) $\left(7.0 \times 10^{-3}\right)-\left(8.0 \times 10^{-4}\right)$
(d) $\left(1.0 \times 10^{4}\right) \times\left(9.9 \times 10^{6}\right)$

Daniel Lai
Daniel Lai
Numerade Educator
01:07

Problem 34

Express the answers to the following calculations in scientific notation:
(a) $0.0095+\left(8.5 \times 10^{-3}\right)$
(b) $653 \div\left(5.75 \times 10^{-8}\right)$
(c) $850,000-\left(9.0 \times 10^{5}\right)$
(d) $\left(3.6 \times 10^{-4}\right) \times\left(3.6 \times 10^{6}\right)$

Himanshu Garg
Himanshu Garg
Numerade Educator
03:52

Problem 35

What is the number of significant figures in each of the following measurements?
(a) $4867 \mathrm{mi}$
(b) $56 \mathrm{~mL}$
(c) 60,104 tons
(d) $2900 \mathrm{~g}$
(e) $40.2 \mathrm{~g} / \mathrm{cm}^{3}$
(f) $0.0000003 \mathrm{~cm}$
(g) $0.7 \mathrm{~min}$
(h) $4.6 \times 10^{19}$ atoms

Daniel Lai
Daniel Lai
Numerade Educator
00:55

Problem 36

How many significant figures are there in each of the following? (a) $0.006 \mathrm{~L},$ (b) $0.0605 \mathrm{dm},$ (c) $60.5 \mathrm{mg}$,
(d) $605.5 \mathrm{~cm}^{2}$
(e) $960 \times 10^{-3} \mathrm{~g},(\mathrm{f}) 6 \mathrm{~kg},(\mathrm{~g}) 60 \mathrm{~m}$

David Collins
David Collins
Numerade Educator
02:15

Problem 37

Carry out the following operations as if they were calculations of experimental results, and express each answer in the correct units with the correct number of significant figures:
(a) $5.6792 \mathrm{~m}+0.6 \mathrm{~m}+4.33 \mathrm{~m}$
(b) $3.70 \mathrm{~g}-2.9133 \mathrm{~g}$
(c) $4.51 \mathrm{~cm} \times 3.6666 \mathrm{~cm}$
(d) $\left(3 \times 10^{4} \mathrm{~g}+6.827 \mathrm{~g}\right) /\left(0.043 \mathrm{~cm}^{3}-0.021 \mathrm{~cm}^{3}\right)$

Oluwapelumi Kolawole
Oluwapelumi Kolawole
Numerade Educator
02:01

Problem 38

Carry out the following operations as if they were calculations of experimental results, and express each answer in the correct units with the correct number of significant figures:
(a) $7.310 \mathrm{~km} \div 5.70 \mathrm{~km}$
(b) $\left(3.26 \times 10^{-3} \mathrm{mg}\right)-\left(7.88 \times 10^{-5} \mathrm{mg}\right)$
(c) $\left(4.02 \times 10^{6} \mathrm{dm}\right)+\left(7.74 \times 10^{7} \mathrm{dm}\right)$
(d) $(7.8 \mathrm{~m}-0.34 \mathrm{~m}) /(1.15 \mathrm{~s}+0.82 \mathrm{~s})$

David Collins
David Collins
Numerade Educator
04:17

Problem 39

Three students $(A, B,$ and $C)$ are asked to determine the volume of a sample of ethanol. Each student measures the volume three times with a graduated cylinder. The results in milliliters are: $\mathrm{A}(87.1,88.2,$ 87.6)$; \mathrm{B}(86.9,87.1,87.2) ; \mathrm{C}(87.6,87.8,87.9) .$ The
true volume is $87.0 \mathrm{~mL}$. Comment on the precision and the accuracy of each student's results.

Ted Gray
Ted Gray
Numerade Educator
01:10

Problem 40

Three apprentice tailors $(\mathrm{X}, \mathrm{Y},$ and $\mathrm{Z})$ are assigned the task of measuring the seam of a pair of trousers. Each one makes three measurements. The results in inches are $\mathrm{X}(31.5,31.6,31.4) ; \mathrm{Y}(32.8,32.3,32.7)$
$\mathrm{Z}(31.9,32.2,32.1) .$ The true length is $32.0 \mathrm{in}$
Comment on the precision and the accuracy of each tailor's measurements.

David Collins
David Collins
Numerade Educator
06:24

Problem 41

Carry out the following conversions:
(a) $22.6 \mathrm{~m}$ to
decimeters, (b) $25.4 \mathrm{mg}$ to kilograms,
(c) $556 \mathrm{~mL}$ to
liters, (d) $10.6 \mathrm{~kg} / \mathrm{m}^{3}$ to $\mathrm{g} / \mathrm{cm}^{3}$.

Daniel Lai
Daniel Lai
Numerade Educator
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Problem 42

Carry out the following conversions: (a) 24216 to milligrams, (b) $68.3 \mathrm{~cm}^{3}$ to cubic meters,
(c) $7.2 \mathrm{~m}^{3}$
to liters,
(d) $28.3 \mu \mathrm{g}$ to pounds.

Ronald Prasad
Ronald Prasad
Numerade Educator
01:25

Problem 43

The average speed of helium at $25^{\circ} \mathrm{C}$ is $1255 \mathrm{~m} / \mathrm{s}$ Convert this speed to miles per hour (mph).

Himanshu Garg
Himanshu Garg
Numerade Educator
01:09

Problem 44

How many seconds are there in a solar year (365.24 days)?

Himanshu Garg
Himanshu Garg
Numerade Educator
04:08

Problem 45

How many minutes does it take light from the sun to reach Earth? (The distance from the sun to Earth is 93 million $\mathrm{mi} ;$ the speed of light $=3.00 \times 10^{8} \mathrm{~m} / \mathrm{s}$.)

Daniel Lai
Daniel Lai
Numerade Educator
01:56

Problem 46

A jogger runs a mile in $8.92 \mathrm{~min}$. Calculate the
(c) $\mathrm{km} / \mathrm{h} .(1 \mathrm{mi}=1609 \mathrm{~m} ;$
speed in (a) in/s, (b) $\mathrm{m} / \mathrm{min}$ 1 in $=2.54 \mathrm{~cm} .)$

David Collins
David Collins
Numerade Educator
01:26

Problem 47

A 6.0 -ft person weighs 168 ib. Express this person's height in meters and weight in kilograms. (1 Ib = $453.6 \mathrm{~g} ; 1 \mathrm{~m}=3.28 \mathrm{ft} .)$

Himanshu Garg
Himanshu Garg
Numerade Educator
00:14

Problem 48

The speed limit on parts of the German autobahn was once set at 286 kilometers per hour (km/h). Calculate the speed limit in miles per hour (mph).

David Collins
David Collins
Numerade Educator
02:24

Problem 49

For a fighter jet to take off from the deck of an aircraft carrier, it must reach a speed of $62 \mathrm{~m} / \mathrm{s}$ Calculate the speed in miles per hour (mph).

Nicole Basile
Nicole Basile
Numerade Educator
01:05

Problem 50

The "normal" lead content in human blood is about 0.40 part per million (that is, $0.40 \mathrm{~g}$ of lead per million grams of blood). A value of 0.80 part per million (ppm) is considered to be dangerous. How many grams of lead are contained in $6.0 \times 10^{3} \mathrm{~g}$ of blood (the amount in an average adult) if the lead content is $0.62 \mathrm{ppm} ?$

Himanshu Garg
Himanshu Garg
Numerade Educator
05:12

Problem 51

Carry out the following conversions: (a) 1.42 lightyears to miles (a light-year is an astronomical measure of distance-the distance traveled by light in a year, or 365 days; the speed of light is $3.00 \times 10^{8} \mathrm{~m} / \mathrm{s}$ ).
(b) 32.4 yd to centimeters.
(c) $3.0 \times 10^{10} \mathrm{~cm} / \mathrm{s}$ to $\mathrm{ft} / \mathrm{s}$

Daniel Lai
Daniel Lai
Numerade Educator
01:10

Problem 52

Carry out the following conversions: (a) $70 \mathrm{~kg}$, the average weight of a male adult, to pounds.
(b) 14 billion years (roughly the age of the universe) to seconds. (Assume there are 365 days in a year.)
(c) $7 \mathrm{ft} 6 \mathrm{in},$ the height of the basketball player $\mathrm{Yao}$ Ming, to meters.
(d) $88.6 \mathrm{~m}^{3}$ to liters.

David Collins
David Collins
Numerade Educator
02:32

Problem 53

Aluminum is a lightweight metal (density $=2.70 \mathrm{~g} / \mathrm{cm}^{3}$ ) used in aircraft construction, high-voltage transmission lines, beverage cans, and foils. What is its density in $\mathrm{kg} / \mathrm{m}^{3} ?$

Daniel Lai
Daniel Lai
Numerade Educator
00:14

Problem 54

Ammonia gas is used as a refrigerant in large-scale cooling systems. The density of ammonia gas under certain conditions is $0.625 \mathrm{~g} / \mathrm{L}$. Calculate its density in $g / \mathrm{cm}^{3}$

David Collins
David Collins
Numerade Educator
01:05

Problem 55

Ammonia gas is used as a refngerant in large-scale cooling systems. The density of ammonia gas under certain conditions is $0.625 \mathrm{~g} / \mathrm{L}$. Calculate its density in $g / \mathrm{cm}^{3}$

Ted Gray
Ted Gray
Numerade Educator
00:53

Problem 56

Which of the following statements describe physical properties and which describe chemical properties?
(a) Iron has a tendency to rust. (b) Rainwater in industrialized regions tends to be acidic. (c) Hemoglobin molecules have a red color. (d) When a glass of water is left out in the sun, the water gradually disappears.
(e) Carbon dioxide in air is converted to more complex molecules by plants during photosynthesis.

David Collins
David Collins
Numerade Educator
01:29

Problem 57

In 2008 , about 95.0 billion Ib of sulfuric acid were produced in the United States. Convert this quantity to tons.

Daniel Lai
Daniel Lai
Numerade Educator
00:37

Problem 58

In determining the density of a rectangular metal bar, a student made the following measurements:
length, $8.53 \mathrm{~cm} ;$ width, $2.4 \mathrm{~cm} ;$ height, $1.0 \mathrm{~cm}$ mass, 52.7064 g. Calculate the density of the metal to the correct number of significant figures.

David Collins
David Collins
Numerade Educator
02:34

Problem 59

Calculate the mass of each of the following: (a) a sphere of gold with a radius of $10.0 \mathrm{~cm}$ [ the volume of a sphere with a radius $r$ is $V=(4 / 3) \pi r^{3} ;$ the density of gold $\left.=19.3 \mathrm{~g} / \mathrm{cm}^{3}\right],$ (b) a cube of platinum of edge length $0.040 \mathrm{~mm}$ (the density of platinum $=$ $\left.21.4 \mathrm{~g} / \mathrm{cm}^{3}\right),$ (c) $50.0 \mathrm{~mL}$ of ethanol (the density of cthanol $=0.798 \mathrm{~g} / \mathrm{mL}$ ).

Nicole Krahulik
Nicole Krahulik
Numerade Educator
View

Problem 60

A cylindrical glass bottle $21.5 \mathrm{~cm}$ in length is tilled with cooking oil of density $0.953 \mathrm{~g} / \mathrm{mL}$. If the mass of the oil needed to fill the bottle is $1360 \mathrm{~g}$, calculate the inner diameter of the bottle.

Tom Comey
Tom Comey
Numerade Educator
01:31

Problem 61

The following procedure was used to determine the volume of a flask. The flask was weighed dry and then filled with water. If the masses of the empty flask and filled flask were $56.12 \mathrm{~g}$ and $87.39 \mathrm{~g},$ respectively, and the density of water is $0.9976 \mathrm{~g} / \mathrm{cm}^{3}$, calculate the volume of the flask in $\mathrm{cm}^{3}$.

Crystal Wang
Crystal Wang
Numerade Educator
00:26

Problem 62

The speed of sound in air at room temperature is about $343 \mathrm{~m} / \mathrm{s}$. Calculate this speed in miles per hour. ( $1 \mathrm{mi}=1609 \mathrm{~m}$.)

David Collins
David Collins
Numerade Educator
03:41

Problem 63

A piece of silver (Ag) metal weighing $194.3 \mathrm{~g}$ is placed in a graduated cylinder containing $242.0 \mathrm{~mL}$ of water. The volume of water now reads $260.5 \mathrm{~mL}$. From these data calculate the density of silver.

Daniel Lai
Daniel Lai
Numerade Educator
00:15

Problem 64

The experiment described in Problem 1.61 is a crude but convenient way to determine the density of some solids. Describe a similar experiment that would enable you to measure the density of ice. Specifically, what would be the requirements for the liquid used in your experiment?

David Collins
David Collins
Numerade Educator
01:48

Problem 65

A lead sphere of diameter $48.6 \mathrm{~cm}$ has a mass of $6.852 \times 10^{5} \mathrm{~g} .$ Calculate the density of lead.

Nicole Krahulik
Nicole Krahulik
Numerade Educator
00:22

Problem 66

Lithium is the least dense metal known (density:
$0.53 \mathrm{~g} / \mathrm{cm}^{3}$ ). What is the volume occupied by $1.20 \times 10^{3} \mathrm{~g}$
of lithium?

David Collins
David Collins
Numerade Educator
05:42

Problem 67

The medicinal thermometer commonly used in homes can be read $\pm 0.1^{\circ} \mathrm{F}$, whereas those in the doctor"s office may be accurate to $\pm 0.1^{\circ} \mathrm{C}$. In degrees Celsius, express the percent error expected from each of these thermometers in measuring a person's body temperature of $38.9^{\circ} \mathrm{C}$.

Daniel Lai
Daniel Lai
Numerade Educator
02:09

Problem 68

Vanillin (used to flavor vanilla ice cream and other foods) is the substance whose aroma the human nose detects in the smallest amount. The threshold limit is $2.0 \times 10^{-11} \mathrm{~g}$ per liter of air. If the current price of $50 \mathrm{~g}$ of vanillin is $$ 112,$ determine the cost to supply enough vanillin so that the aroma could be detected in a large aircraft hangar with a volume of $5.0 \times 10^{7} \mathrm{ft}^{3}$

Himanshu Garg
Himanshu Garg
Numerade Educator
02:15

Problem 69

At what temperature does the numerical reading on a Celsius thermometer equal that on a Fahrenheit thermometer?

Daniel Lai
Daniel Lai
Numerade Educator
01:20

Problem 70

Suppose that a new temperature scale has been devised on which the melting point of ethanol $\left(-117.3^{\circ} \mathrm{C}\right)$ and the boiling point of ethanol $\left(78.3^{\circ} \mathrm{C}\right)$ are taken as $0^{\circ} \mathrm{S}$ and $100^{\circ} \mathrm{S},$ respectively where $S$ is the symbol for the new temperature scale. Derive an equation relating a reading on this scale to a reading on the Celsius scale. What would this thermometer read at $25^{\circ} \mathrm{C}$ ?

David Collins
David Collins
Numerade Educator
View

Problem 71

A resting adult requires about $240 \mathrm{~mL}$ of pure oxygen min and breathes about 12 times every minute. If inhaled air contains 20 percent oxygen by volume and exhaled air 16 percent, what is the volume of air per breath? (Assume that the volume of inhaled air is equal to that of exhaled air.)

Susan Hallstrom
Susan Hallstrom
Numerade Educator
View

Problem 72

(a) Referring to Problem 1.71 , calculate the total volume (in liters) of air an adult breathes in a day.
(b) In a city with heavy traffic, the air contains $2.1 \times$ $10^{-6} \mathrm{~L}$ of carbon monoxide (a poisonous gas) per liter. Calculate the average daily intake of carbon monoxide in liters by a person.

Ronald Prasad
Ronald Prasad
Numerade Educator
View

Problem 73

Three different $25.0-\mathrm{g}$ samples of solid pellets are added to $20.0 \mathrm{~mL}$ of water in three different measuring cylinders. The results are shown here. Given the densities of the three metals used, identify the cylinder that contains each sample of solid pellets: A $(2.9 \mathrm{~g} /$ $\left.\mathrm{cm}^{3}\right), \mathrm{B}\left(8.3 \mathrm{~g} / \mathrm{cm}^{3}\right),$ and $\mathrm{C}\left(3.3 \mathrm{~g} / \mathrm{cm}^{3}\right)$
a.
b.
c.

Nicole Basile
Nicole Basile
Numerade Educator
01:42

Problem 74

The circumference of an NBA-approved basketball is 29.6 in. Given that the radius of Earth is about $6400 \mathrm{~km},$ how many basketballs would it take to circle around the equator with the basketballs touching one another? Round off your answer to an integer with three significant figures.

David Collins
David Collins
Numerade Educator
03:14

Problem 75

A student is given a crucible and asked to prove whether it is made of pure platinum. She first weighs the crucible in air and then weighs it suspended in water (density $=0.9986 \mathrm{~g} / \mathrm{mL}$ ). The readings are $860.2 \mathrm{~g}$ and $820.2 \mathrm{~g},$ respectively. Based on these measurements and given that the density of platinum is $21.45 \mathrm{~g} / \mathrm{cm}^{3},$ what should her conclusion be? (Hint: An object suspended in a fluid is buoyed up by the mass of the fluid displaced by the object. Neglect the buoyance of air.)

Crystal Wang
Crystal Wang
Numerade Educator
00:35

Problem 76

The surface area and average depth of the Pacific Ocean are $1.8 \times 10^{8} \mathrm{~km}^{2}$ and $3.9 \times 10^{3} \mathrm{~m},$ respectively. Calculate the volume of water in the ocean in liters.

David Collins
David Collins
Numerade Educator
01:47

Problem 77

The unit "troy ounce" is often used for precious metals such as gold (Au) and platinum ( $\mathrm{Pt}$ ). ( 1 troy ounce $=31.103$ g.) (a) A gold coin weighs 2.41 troy ounces. Calculate its mass in grams.
(b) Is a troy ounce heavier or lighter than an ounce? ( $1 \mathrm{lb}=$ $160 z ; 1 \mathrm{lb}=453.6 \mathrm{~g} .)$

Nicole Krahulik
Nicole Krahulik
Numerade Educator
01:43

Problem 78

Osmium (Os) is the densest element known (density $=22.57 \mathrm{~g} / \mathrm{cm}^{3}$ ). Calculate the mass in pounds and in kilograms of an Os sphere $15 \mathrm{~cm}$ in diameter (about the size of a grapefruit). [The volume of a sphere of radius $r$ is $\left.(4 / 3) \pi r^{3} \cdot\right]$

Himanshu Garg
Himanshu Garg
Numerade Educator
02:54

Problem 79

Percent error is often expressed as the absolute value of the difference between the true value and the experimental value, divided by the true value:
percent error $=\frac{\mid \text { true value }-\text { experimental value } \mid}{\mid \text { true value } \mid} \times 100 \%$
The vertical lines indicate absolute value. Calculate the percent error for the following measurements:
(a) The density of alcohol (ethanol) is found to be $0.802 \mathrm{~g} / \mathrm{mL}$. (True value: $0.798 \mathrm{~g} / \mathrm{mL}$.) (b) The mass of gold in an earring is analyzed to be $0.837 \mathrm{~g}$. (True value: $0.864 \mathrm{~g}$.)

Daniel Lai
Daniel Lai
Numerade Educator
01:47

Problem 80

The natural abundances of elements in the human body, expressed as percent by mass, are: oxygen (O),65 percent; carbon $(\mathrm{C}), 18$ percent; hydrogen
(H), 10 percent; nitrogen (N), 3 percent; calcium (Ca), 1.6 percent; phosphorus ( $\mathrm{P}$ ), 1.2 percent; all other elements, 1.2 percent. Calculate the mass in grams of each element in the body of a $62-\mathrm{kg}$ person.

Himanshu Garg
Himanshu Garg
Numerade Educator
03:09

Problem 81

The men's world record for running a mile outdoors (as of 1999 ) is 3 min 43.13 s. At this rate, how long would it take to run a $1500-\mathrm{m}$ race? $(1 \mathrm{mi}$ $=1609 \mathrm{~m} .)$

Daniel Lai
Daniel Lai
Numerade Educator
00:27

Problem 82

Venus, the second closest planet to the sun, has a surface temperature of $7.3 \times 10^{2} \mathrm{~K}$. Convert this temperature to ${ }^{\circ} \mathrm{C}$ and ${ }^{\circ} \mathrm{F}$.

David Collins
David Collins
Numerade Educator
01:02

Problem 83

Chalcopyrite, the principal ore of copper $(\mathrm{Cu})$ contains 34.63 percent Cu by mass. How many grams of Cu can be obtained from $5.11 \times 10^{3} \mathrm{~kg}$ of the ore?

Himanshu Garg
Himanshu Garg
Numerade Educator
02:03

Problem 84

It has been estimated that $8.0 \times 10^{-4}$ tons of gold (Au) have been mined. Assume gold costs $\$ 948$ per ounce. What is the total worth of this quantity of gold?

Ted Gray
Ted Gray
Numerade Educator
04:46

Problem 85

A $1.0-\mathrm{mL}$ volume of seawater contains about $4.0 \times 10^{-12} \mathrm{~g}$ of gold. The total volume of ocean water is $1.5 \times 10^{21} \mathrm{~L}$. Calculate the total amount of gold (in grams) that is present in seawater, and the worth of the gold in dollars (see Problem 1.84). With so much gold out there, why hasn't someone become rich by mining gold from the ocean?

Daniel Lai
Daniel Lai
Numerade Educator
00:44

Problem 86

Measurements show that $1.0 \mathrm{~g}$ of iron (Fe) contains $1.1 \times 10^{22}$ Fe atoms. How many Fe atoms are in $4.9 \mathrm{~g}$ of Fe, which is the total amount of iron in the body of an average adult?

Himanshu Garg
Himanshu Garg
Numerade Educator
03:40

Problem 87

The thin outer layer of Earth, called the crust, contains only 0.50 percent of Earth's total mass and yet is the source of almost all the elements (the atmosphere provides elements such as oxygen, nitrogen, and a few other gases). Silicon (Si) is the second most abundant element in Earth's crust (27.2 percent by mass). Calculate the mass of silicon in kilograms in Earth's crust. (The mass of Earth is $5.9 \times 10^{21}$ tons. 1 ton $=2000 \mathrm{lb} ; 1 \mathrm{lb}=$ $453.6 \mathrm{~g} .)$

Daniel Lai
Daniel Lai
Numerade Educator
01:04

Problem 88

The radius of a copper (Cu) atom is roughly $1.3 \times$ $10^{-10} \mathrm{~m} .$ How many times can you divide evenly a piece of $10-\mathrm{cm}$ copper wire until it is reduced to two separate copper atoms? (Assume there are appropriate tools for this procedure and that copper atoms are lined up in a straight line, in contact with each other. Round off your answer to an integer.)

David Collins
David Collins
Numerade Educator
02:46

Problem 89

One gallon of gasoline in an automobile's engine produces on the average $9.5 \mathrm{~kg}$ of carbon dioxide, which is a greenhouse gas, that is, it promotes the warming of Earth's atmosphere. Calculate the annual production of carbon dioxide in kilograms if there are 250 million cars in the United States and each car covers a distance of $5000 \mathrm{mi}$ at a consumption rate of 20 miles per gallon.

Daniel Lai
Daniel Lai
Numerade Educator
01:40

Problem 90

A sheet of aluminum (AI) foil has a total area of $1.000 \mathrm{ft}^{2}$ and a mass of $3.636 \mathrm{~g}$. What is the thickness of the foil in millimeters? (Density of Al = $\left.2.699 \mathrm{~g} / \mathrm{cm}^{3} .\right)$

Narayan Hari
Narayan Hari
Numerade Educator
00:43

Problem 91

Comment on whether each of the following is a homogeneous mixture or a heterogeneous mixture:
(a) air in a closed bottle, (b) air over New York City.

Himanshu Garg
Himanshu Garg
Numerade Educator
00:58

Problem 92

Chlorine is used to disinfect swimming pools. The accepted concentration for this purpose is 1 ppm chlorine, or $1 \mathrm{~g}$ of chlorine per million grams of water. Calculate the volume of a chlorine solution (in milliliters) a homeowner should add to her swimming pool if the solution contains 6.0 percent chlorine by mass and there are $2.0 \times 10^{4}$ gallons of water in the pool. ( 1 gallon $=3.79 \mathrm{~L} ;$ density of liquids $=1.0 \mathrm{~g} / \mathrm{mL} .

David Collins
David Collins
Numerade Educator
03:21

Problem 93

An aluminum cylinder is $10.0 \mathrm{~cm}$ in length and has a radius of $0.25 \mathrm{~cm}$. If the mass of a single Al atom is $4.48 \times 10^{-23} \mathrm{~g},$ calculate the number of $\mathrm{Al}$ atoms present in the cylinder. The density of aluminum is $2.70 \mathrm{~g} / \mathrm{cm}^{3}.

Daniel Lai
Daniel Lai
Numerade Educator
02:18

Problem 94

A pycnometer is a device for measuring the density of liquids. It is a glass flask with a close-fitting ground glass stopper having a capillary hole through it. (a) The volume of the pycnometer is determined by using distilled water at $20^{\circ} \mathrm{C}$ with a known density of $0.99820 \mathrm{~g} / \mathrm{mL}$. First, the water is filled to the rim. With the stopper in place, the fine hole allows the excess liquid to escape. The pycnometer is then carefully dried with filter paper. Given that the masses of the empty pycnometer and the same one filled with water are $32.0764 \mathrm{~g}$ and $43.1195 \mathrm{~g},$ respectively, calculate the volume of the pycnometer. (b) If the mass of the pycnometer filled with ethanol at $20^{\circ} \mathrm{C}$ is $40.8051 \mathrm{~g},$ calculate the density of ethanol. (c) Pycnometers can also be used to measure the density of solids. First, small zinc granules weighing $22.8476 \mathrm{~g}$ are placed in the pycnometer, which is then filled with water. If the combined mass of the pycnometer plus the zinc granules and water is $62.7728 \mathrm{~g}$. what is the density of zinc?

David Collins
David Collins
Numerade Educator
03:06

Problem 95

In 1849 a gold prospector in California collected a bag of gold nuggets plus sand. Given that the density of gold and sand are $19.3 \mathrm{~g} / \mathrm{cm}^{3}$ and $2.95 \mathrm{~g} / \mathrm{cm}^{3}$. respectively, and that the density of the mixture is $4.17 \mathrm{~g} / \mathrm{cm}^{3},$ calculate the percent by mass of gold in the mixture.

Cheryl Glor
Cheryl Glor
Numerade Educator
00:27

Problem 96

The average time it takes for a molecule to diffuse a distance of $x \mathrm{~cm}$ is given by
$$ t=\frac{x^{2}}{2 D} $$where $t$ is the time in seconds and $D$ is the diffusion coefficient. Given that the diffusion coefficient of glucose is $5.7 \times 10^{-7} \mathrm{~cm}^{2} / \mathrm{s},$ calculate the time it would take for a glucose molecule to diffuse $10 \mu \mathrm{m}$, which is roughly the size of a cell.

David Collins
David Collins
Numerade Educator
View

Problem 97

A human brain weighs about $1 \mathrm{~kg}$ and contains about $10^{11}$ cells. Assuming that each cell is com pletely filled with water (density $=1 \mathrm{~g} / \mathrm{mL}$ ), calculate the length of one side of such a cell if it were a cube. If the cells are spread out in a thin layer that is a single cell thick, what is the surface area in square meters?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:01

Problem 98

(a) Carbon monoxide (CO) is a poisonous gas because it binds very strongly to the oxygen carrier hemoglobin in blood. A concentration of $8.00 \times 10^{2}$ ppm by volume of carbon monoxide is considered lethal to humans. Calculate the volume in liters occupied by carbon monoxide in a room that measures $17.6 \mathrm{~m}$ long, $8.80 \mathrm{~m}$ wide, and $2.64 \mathrm{~m}$ high at this concentration.
(b) Prolonged exposure to mercury (Hg) vapor can cause neurological disorder and respiratory problems. For safe air quality control, the concentration of mercury vapor must be under $0.050 \mathrm{mg} / \mathrm{m}^{3}$. Convert this number to g/L. (c) The general test for type II diabetes is that the blood sugar (glucose) level should be below $120 \mathrm{mg}$ per deciliter $(\mathrm{mg} / \mathrm{dL})$. Convert this number to micrograms per milliliter ( $\mu \mathrm{g} / \mathrm{mL}$ ).

David Collins
David Collins
Numerade Educator
04:07

Problem 99

A bank teller is asked to assemble "one-dollar" sets of coins for his clients. Each set is made of three quarters, one nickel, and two dimes. The masses of the coins are: quarter: 5.645 g; nickel: $4.967 \mathrm{~g}$ dime: 2.316 g. What is the maximum number of sets that can be assembled from $33.871 \mathrm{~kg}$ of quarters, $10.432 \mathrm{~kg}$ of nickels, and $7.990 \mathrm{~kg}$ of dimes? What is the total mass (in g) of the assembled sets of coins?

Crystal Wang
Crystal Wang
Numerade Educator
03:30

Problem 100

A graduated cylinder is tilled to the $40.00-\mathrm{mL}$ mark with a mineral oil. The masses of the cylinder before and after the addition of the mineral oil are $124.966 \mathrm{~g}$ and $159.446 \mathrm{~g},$ respectively. In a separate experiment, a metal ball bearing of mass $18.713 \mathrm{~g}$ is placed in the cylinder and the cylinder is again filled to the 40.00 -mL mark with the mineral oil. The combined mass of the ball bearing and mineral oil is 50.952 g. Calculate the density and radius of the ball bearing. [The volume of a sphere of radius $r$ is $\left.(4 / 3) \pi r^{3} .\right].

Prashant Bana
Prashant Bana
Numerade Educator
03:39

Problem 101

A cobalt bar (density $=8.90 \mathrm{~g} / \mathrm{cm}^{3}$ ) is shown here. What is the mass of this bar to the appropriate number of significant figures?

Cheryl Glor
Cheryl Glor
Numerade Educator
View

Problem 102

Bronze is an alloy made of copper (Cu) and tin (Sn) used in applications that require low metalon-metal friction. Calculate the mass of a bronze cylinder of radius $6.44 \mathrm{~cm}$ and length $44.37 \mathrm{~cm} .$ The composition of the bronze is 79.42 percent Cu and 20.58 percent Sn and the densities of Cu and $\mathrm{Sn}$ are $8.94 \mathrm{~g} / \mathrm{cm}^{3}$ and $7.31 \mathrm{~g} / \mathrm{cm}^{3},$ respec-
tively. What assumption should you make in this calculation?

Tom Comey
Tom Comey
Numerade Educator
00:32

Problem 103

You are given a liquid. Briefly describe steps you would take to show whether it is a pure substance or a homogeneous mixture.

Himanshu Garg
Himanshu Garg
Numerade Educator
01:25

Problem 104

A chemist mixes two liquids $A$ and $B$ to form a homogeneous mixture. The densities of the liquids are $2.0514 \mathrm{~g} / \mathrm{mL}$ for $\mathrm{A}$ and $2.6678 \mathrm{~g} / \mathrm{mL}$ for $\mathrm{B}$. When
she drops a small object into the mixture, she finds that the object becomes suspended in the liquid; that is, it neither sinks nor floats. If the mixture is made of 41.37 percent $A$ and 58.63 percent $B$ by volume, what is the density of the metal? Can this procedure be used in general to determine the densities of solids? What assumptions must be made in applying this method?

David Collins
David Collins
Numerade Educator
01:44

Problem 105

Tums is a popular remedy for acid indigestion. A typical Tums tablet contains calcium carbonate plus some inert substances. When ingested, it reacts with the gastric juice (hydrochloric acid) in the stomach to give off carbon dioxide gas. When a $1.328-g$ tablet reacted with $40.00 \mathrm{~mL}$ of hydrochloric acid (density: $1.140 \mathrm{~g} / \mathrm{mL}),$ carbon dioxide gas was given off and the resulting solution weighed 46.699 g. Calculate the number of liters of carbon dioxide gas released if its density is $1.81 \mathrm{~g} / \mathrm{L}.

Himanshu Garg
Himanshu Garg
Numerade Educator
00:21

Problem 106

A $250-\mathrm{mL}$ glass bottle was filled with $242 \mathrm{~mL}$ of water at $20^{\circ} \mathrm{C}$ and tightly capped. It was then left outdoors overnight, where the average temperature was $-5^{\circ} \mathrm{C}$. Predict what would happen. The density of water at $20^{\circ} \mathrm{C}$ is $0.998 \mathrm{~g} / \mathrm{cm}^{3}$ and that of ice at $-5^{\circ} \mathrm{C}$ is $0.916 \mathrm{~g} / \mathrm{cm}^{3}.

David Collins
David Collins
Numerade Educator
01:04

Problem 107

What is the mass of one mole of ants? (Useful information: A mole is the unit used for atomic and subatomic particles. It is approximately $6 \times 10^{23}$. A $1-\mathrm{cm}$ -long ant weighs about $3 \mathrm{mg}$.

Daniel Lai
Daniel Lai
Numerade Educator
00:14

Problem 108

How much time (in years) does an 80 -year-old person spend sleeping during his or her life span?

David Collins
David Collins
Numerade Educator
01:24

Problem 109

Estimate the daily amount of water (in gallons) used indoors by a family of four in the United States.

Cheryl Glor
Cheryl Glor
Numerade Educator
01:47

Problem 110

Public bowling alleys generally stock bowling balls from 8 to $16 \mathrm{lb},$ where the mass is given in whole numbers, Given that regulation bowling balls have a diameter of 8.6 in, which (if any) of these bowling balls would you expect to float in water?

David Collins
David Collins
Numerade Educator
02:04

Problem 111

Fusing "nanofibers" with diameters of 100
to $300 \mathrm{nm}$ gives junctures with very small volumes that would potentially allow the study of reactions in volving only a few molecules. Estimate the volume in liters of the junction formed between two such fibers with internal diameters of $200 \mathrm{nm}$. The scale reads $1 \mu \mathrm{m}$.

Kratika Bhadauria
Kratika Bhadauria
Numerade Educator
00:06

Problem 112

Estimate the annual consumption of gasoline by passenger cars in the United States.

David Collins
David Collins
Numerade Educator
02:11

Problem 113

\text { Estimate the total amount of ocean water in liters.

Cheryl Glor
Cheryl Glor
Numerade Educator
00:08

Problem 114

\text { Estimate the volume of blood in an adult in liters.

David Collins
David Collins
Numerade Educator
01:40

Problem 115

How far (in feet) does light travel in one nanosecond?

Rashmi Sinha
Rashmi Sinha
Numerade Educator
01:08

Problem 116

Estimate the distance (in miles) covered by an NBA player in a professional basketball game.

David Collins
David Collins
Numerade Educator
01:35

Problem 117

In water conservation, chemists spread a thin film of a certain inert material over the surface of water to cut down on the rate of evaporation of water in reservoirs. This technique was pioneered by Benjamin Franklin three centuries ago. Franklin found that $0.10 \mathrm{~mL}$ of oil could spread over the surface of water about $40 \mathrm{~m}^{2}$ in area. Assuming that the oil forms a monolayer, that is, a layer that is only one molecule thick, estimate the length of each oil molecule in nanometers. $\left(1 \mathrm{nm}=1 \times 10^{-9} \mathrm{~m} .\right).

Himanshu Garg
Himanshu Garg
Numerade Educator