Chemistry. The Central Science in SI Units

Bruce E. Bursten, Catherine Murphy, H. Eugene LeMay, Matthew E. Stoltzfus, Patrick Woodward, Theodore E. Brown

Chapter 1

Introduction: Matter Energy and Measurement - all with Video Answers

Educators

Chapter Questions

Problem 1

Which of the following figures represents (a) a pure element, (b) a mixture of two elements, (c) a pure compound, (d) a mixture of an element and a compound? (More than one picture might fit each description.) [Section 1.2]
(i) FIGURE CAN'T COPY.
(ii) FIGURE CAN'T COPY.
(iii) FIGURE CAN'T COPY.
(iv) FIGURE CAN'T COPY.
(v) FIGURE CAN'T COPY.
(vi) FIGURE CAN'T COPY.

Susan Hallstrom

Susan Hallstrom

Numerade Educator

Problem 2

Which of the following diagrams represents a chemical change? [Section 1.3]
(a) FIGURE CAN'T COPY.
(b) FIGURE CAN'T COPY.

Brooke Smith

Numerade Educator

Problem 3

Musical instruments like trumpets and trombones are made from an alloy called brass. Brass is composed of copper and zinc atoms and appears homogeneous under an optical microscope. The approximate composition of most brass objects is a 2:1 ratio of copper to zinc atoms, but the exact ratio varies somewhat from one piece of brass to another. (a) Would you classify brass as an element, a compound, a homogeneous mixture, or a heterogeneous mixture? (b) Would it be correct to say that brass is a solution? [Section 1.2]
FIGURE CAN'T COPY.

Zaida Minjares

Numerade Educator

Problem 4

Consider the two spheres shown here, one made of silver and the other of aluminum. (a) What is the mass of each sphere in $\mathrm{kg}$ ? (b) The force of gravity acting on an object is $F=m g$, where $m$ is the mass of an object and $g$ is the acceleration of gravity $\left(9.8 \mathrm{~m} / \mathrm{s}^2\right)$. How much work do you do on each sphere it you raise it from the floor to a height of $2.2 \mathrm{~m}$ ? (c) Does the act of lifting the sphere off the ground increase the potential energy of the aluminum sphere by a larger, smaller, or same amount as the silver sphere? (d) If you release the spheres simultaneously, they will have the same velocity when they hit the ground. Will they have the same kinetic energy? If not, which sphere will have more kinetic energy? [Section 1.4]
FIGURE CAN'T COPY.

Keenan Mintz

University of Miami

Problem 5

Is the separation method used in brewing a cup of coffee best described as distillation, filtration, or chromatography? [Section 1.3]
FIGURE CAN'T COPY.

Mercedes Mazza

Numerade Educator

Problem 6

Identify each of the following as measurements of length, area, volume, mass, density, time, or temperature: (a) $25 \mathrm{ps}$, (b) $374.2 \mathrm{mg}$, (c) $77 \mathrm{~K}$, (d) $100,000 \mathrm{~km}^2$, (e) $1.06 \mu \mathrm{m}$, (f) $16 \mathrm{~nm}^2$, (g) $-78^{\circ} \mathrm{C}$, (h) $2.56 \mathrm{~g} / \mathrm{cm}^3$, (i) $28 \mathrm{~cm}^3$. [Section 1.5 ]

Keenan Mintz

University of Miami

Problem 7

(a) Three spheres of equal size are composed of aluminum (density $\left.=2.70 \mathrm{~g} / \mathrm{cm}^3\right)$, silver $\left(\right.$ density $\left.=10.49 \mathrm{~g} / \mathrm{cm}^3\right)$, and nickel (density $=8.90 \mathrm{~g} / \mathrm{cm}^3$ ). List the spheres from lightest to heaviest. (b) Three cubes of equal mass are composed of gold (density $=19.32 \mathrm{~g} / \mathrm{cm}^3$ ), platinum $\left(\right.$ density $\left.=21.45 \mathrm{~g} / \mathrm{cm}^3\right)$, and lead $\left(\right.$ density $\left.=11.35 \mathrm{~g} / \mathrm{cm}^3\right)$. List the cubes from smallest to largest. [Section 1.5]

Mercedes Mazza

Numerade Educator

Problem 8

The three targets from a rifle range shown below were produced by: (A) the instructor firing a newly acquired target rifle; (B) the instructor firing his personal target rifle; and (C) a student who has fired his target rifle only a few times.
(a) Comment on the accuracy and precision for each of these three sets of results. (b) For the $\mathrm{A}$ and $\mathrm{C}$ results in the future to look like those in B, what needs to happen? [Section 1.6]
A FIGURE CAN'T COPY.
B FIGURE CAN'T COPY.
C FIGURE CAN'T COPY.

Keenan Mintz

University of Miami

Problem 9

(a) What is the length of the pencil in the following figure if the ruler reads in centimeters? How many significant figures are there in this measurement? (b) An automobile speedometer with circular scales reading both miles per hour and kilometers per hour is shown. What speed is indicated, in both units? How many significant figures are in the measurements? [Section 1.6]
FIGURE CAN'T COPY.

Mercedes Mazza

Numerade Educator

Problem 10

(a) How many significant figures should be reported for the volume of the metal bar shown here? (b) If the mass of the bar is $104.72 \mathrm{~g}$, how many significant figures should be reported when its density is determined using the calculated volume? [Section 1.6]
FIGURE CAN'T COPY.

Zaida Minjares

Numerade Educator

Problem 11

Consider the jar of jelly beans in the photo. To get an estimate of the number of beans in the jar you weigh six beans and obtain masses of $3.15,3.12,2.98,3.14,3.02$, and $3.09 \mathrm{~g}$. Then you weigh the jar with all the beans in it, and obtain a mass of $2082 \mathrm{~g}$. The empty jar has a mass of $653 \mathrm{~g}$. Based on these data, estimate the number of beans in the jar. Justify the number of significant figures you use in your estimate. [Section 1.6]
FIGURE CAN'T COPY.

Mercedes Mazza

Numerade Educator

Problem 12

The photo below shows a picture of an agate stone. Jack, who picked up the stone on the Lake Superior shoreline and polished it, insists that agate is a chemical compound. Ellen argues that it cannot be a compound. Discuss the relative merits of their positions. [Section 1.2]
FIGURE CAN'T COPY.

Keenan Mintz

University of Miami

Problem 13

Classify each of the following as a pure substance or a mixture. If a mixture, indicate whether it is homogeneous or heterogeneous: (a) air, (b) chocolate with almond, (c) aluminium, (d) iodine tincture.

Zaida Minjares

Numerade Educator

Problem 14

Classify each of the following as a pure substance or a mixture. If a mixture, indicate whether it is homogeneous or heterogeneous: (a) milk, (b) beer, (c) diamond, (d) mayonnaise.

Zaida Minjares

Numerade Educator

Problem 15

Give the chemical symbol or name for the following elements, as appropriate: (a) helium, (b) platinum, (c) cobalt, (d) tin, (e) silver, (f) $\mathrm{Sb},($ g) $\mathrm{Pb}$, (h) $\mathrm{Br}$, (i) $\mathrm{V}$, (j) $\mathrm{Hg}$.

Zaida Minjares

Numerade Educator

Problem 16

Give the chemical symbol or name for each of the following elements, as appropriate: (a) rhenium, (b) tungsten, (c) caesium, (d) hydrogen, (e) indium, (f) As, (g) $\mathrm{Xe}$, (h) $\mathrm{Kr}$, (i) $\mathrm{Te}$, (i) Ge.

Zaida Minjares

Numerade Educator

Problem 17

A solid white substance $A$ is heated strongly in the absence of air. It decomposes to form a new white substance $B$ and a gas $C$. The gas has exactly the same properties as the product obtained when carbon is burned in an excess of oxygen. Based on these observations, can we determine whether solids $A$ and $B$ and gas $C$ are elements or compounds?

Mercedes Mazza

Numerade Educator

Problem 18

Zirconia, an oxide of zirconium, is often used as an affordable diamond substitute. Just like diamond, it is a colorless crystal which sparkles under sunlight. Which of the following physical properties do you think would help in differentiating between diamond and Zirconia-melting point, density, or physical state?

Nicole Smina

Numerade Educator

Problem 19

In the process of attempting to characterize a substance, a chemist makes the following observations: The substance is a silvery white, lustrous metal. It melts at $649^{\circ} \mathrm{C}$ and boils at $1105^{\circ} \mathrm{C}$. Its density at $20^{\circ} \mathrm{C}$ is $1.738 \mathrm{~g} / \mathrm{cm}^3$. The substance burns in air, producing an intense white light. It reacts with chlorine to give a brittle white solid. The substance can be pounded into thin sheets or drawn into wires. It is a good conductor of electricity. Which of these characteristics are physical properties, and which are chemical properties?

Lottie Adams

Numerade Educator

Problem 20

(a) Read the following description of the element zinc and indicate which are physical properties and which are chemical properties.
Zinc melts at $420^{\circ} \mathrm{C}$. When zinc granules are added to dilute sulfuric acid, hydrogen is given off and the metal dissolves. Zinc has a hardness on the Mohs scale of 2.5 and a density of $7.13 \mathrm{~g} / \mathrm{cm}^3$ at $25^{\circ} \mathrm{C}$. It reacts slowly with oxygen gas at elevated temperatures to form zinc oxide, $\mathrm{ZnO}$.
(b) Which properties of zinc can you describe from the photo? Are these physical or chemical properties?
FIGURE CAN'T COPY.

Keenan Mintz

University of Miami

Problem 21

Label each of the following as either a physical process or a chemical process: (a) crushing a metal can, (b) production of urine in the kidneys, (c) melting a piece of chocolate, (d) burning fossil fuel, (e) discharging a battery.

Zaida Minjares

Numerade Educator

Problem 22

A match is lit to light a candle. The following observations are made: (a) The candle burns. (b) Some wax melts. (c) Melted wax solidifies on the candleholder. (d) Soot (carbon) is produced by the burning of the match and the candle. Which of these occurrences are due to physical changes, and which are due to chemical changes?

Lottie Adams

Numerade Educator

Problem 23

Which separation method is better suited for obtaining sugar from cane juice-filtration or evaporation?

Nicole Smina

Numerade Educator

Problem 24

A silvery metal is put inside a beaker of water. Bubbles form on the surface of the metal and it dissolves gradually. (a) Is this an example of a chemical or a physical change? (b) Do you expect the remaining solution to be a pure substance or a mixture?

Zaida Minjares

Numerade Educator

Problem 25

(a) Calculate the kinetic energy, in joules, of a $15-\mathrm{g}$ bullet moving at $120 \mathrm{~m} / \mathrm{s}$. (b) Convert this energy to calories.
(c) When the bullet is stopped by a bulletproof vest, which form of energy does the kinetic energy of the bullet convert to?

Zaida Minjares

Numerade Educator

Problem 26

(a) A baseball weighs $145.4 \mathrm{~g}$. What is the kinetic energy, in joules, of this baseball when it is thrown by a major league pitcher at $150 \mathrm{~km} / \mathrm{h}$ ? (b) By what factor will the kinetic energy change if the speed of the baseball is decreased to $90 \mathrm{~km} / \mathrm{h}$ ? (c) What happens to the kinetic energy when the baseball is caught by the catcher? Is it converted mostly to heat or to some form of potential energy?

Nicole Wood

Numerade Educator

Problem 27

Two positively charged particles are first brought close together and then released. Once released, the repulsion between particles causes them to move away from each other. (a) This is an example of potential energy being converted into what form of energy? (b) Does the potential energy of the two particles prior to release increase or decrease as the distance between them is increased.

Mercedes Mazza

Numerade Educator

Problem 28

For each of the following processes, does the potential energy of the object(s) increase or decrease? (a) The charge of two oppositely charged particles is increased. (b) $\mathrm{H}_2 \mathrm{O}$ molecule is split into two oppositely charged ions, $\mathrm{H}^{+}$and $\mathrm{OH}^{-}$. (c) A person skydives from a height of 600 meters.

Susan Hallstrom

Susan Hallstrom

Numerade Educator

Problem 29

What is the kinetic energy and velocity of the aluminum sphere in Problem 1.4 at the moment it hits the ground? (Assume that energy is conserved during the fall and that $100 \%$ of the sphere's initial potential energy is converted to kinetic energy by the time impact occurs.)

Mercedes Mazza

Numerade Educator

Problem 30

What is the kinetic energy and velocity of the silver sphere in Problem 1.4 at the moment it hits the ground? (Assume that energy is conserved during the fall and that $100 \%$ of the sphere's initial potential energy is converted to kinetic energy by the time impact occurs.)

Ronald Prasad

Numerade Educator

Problem 31

Convert the following expressions into exponential notation: (a) 3 terameters (tm) (b) 2.5 femtoseconds (fs) (c) 57 micrometers $(\mu m)(\mathbf{d}) 8.3$ megagrams (mg).

Nicole Wood

Numerade Educator

Problem 32

Use appropriate metric prefixes to write the following measurements without use of exponents: (a) $7.29 \times 10^6 \mathrm{~g}$ (b) $6.1 \times 10^{-10} \mathrm{~m}$ (c) $1.828 \times 10^{-3} \mathrm{~s}$ (d) $3.523 \times 10^9 \mathrm{~m}^3$ (e) $9.62 \times 10^2 \mathrm{~m} / \mathrm{s}\left(\right.$ f) $8.923 \times 10^{-12} \mathrm{~kg}$ (g) $3.552 \times 10^{12} \mathrm{~L}$.

Willis James

Numerade Educator

Problem 33

Make the following conversions: (a) $83^{\circ} \mathrm{F}$ to ${ }^{\circ} \mathrm{C}$ (b) $29^{\circ} \mathrm{C}$ to ${ }^{\circ} \mathrm{F}$ (c) $294^{\circ} \mathrm{C}$ to $\mathrm{K}$ (d) $832 \mathrm{~K}$ to ${ }^{\circ} \mathrm{C}$ (e) $721 \mathrm{~K}$ to ${ }^{\circ} \mathrm{F}$ (f) $35^{\circ} \mathrm{F}$ to $\mathrm{K}$.

Zaida Minjares

Numerade Educator

Problem 34

(a) A child has a fever of $101^{\circ} \mathrm{F}$. What is the temperature in ${ }^{\circ} \mathrm{C}$ ? (b) In a desert, the temperature can be as high as $45^{\circ} \mathrm{C}$, what is the temperature in ${ }^{\circ} \mathrm{F}$ ? (c) During winter, the temperature of the Arctic region can drop below $-50^{\circ} \mathrm{C}$, what is the temperature in degree Fahrenheit and in Kelvin? (d) The sublimation temperature of dry ice is $-78.5^{\circ} \mathrm{C}$. Convert this temperature to degree Fahrenheit and Kelvin. (e) Ethanol boils at 351 K. Convert this temperature to degree Fahrenheit and degree Celsius.

Zaida Minjares

Numerade Educator

Problem 35

(a) A sample of tetrachloroethylene, a liquid used in dry cleaning that is being phased out because of its potential to cause cancer, has a mass of $40.55 \mathrm{~g}$ and a volume of $25.0 \mathrm{~mL}$ at $25^{\circ} \mathrm{C}$. What is its density at this temperature? Will tetrachloroethylene float on water? (Materials that are less dense than water will float.) (b) Carbon dioxide $\left(\mathrm{CO}_2\right)$ is a gas at room temperature and pressure. However, carbon dioxide can be put under pressure to become a "supercritical fluid" that is a much safer dry-cleaning agent than tetrachloroethylene. At a certain pressure, the density of supercritical $\mathrm{CO}_2$ is $0.469 \mathrm{~g} / \mathrm{cm}^3$. What is the mass of a $25.0-\mathrm{mL}$ sample of supercritical $\mathrm{CO}_2$ at this pressure?

Nicole Wood

Numerade Educator

Problem 36

(a) What is the mass of a silver cube whose edges measure 2.00 $\mathrm{cm}$ each at $25^{\circ} \mathrm{C}$ ? The density of silver is $10.49 \mathrm{~g} / \mathrm{cm}^3$ at $25^{\circ} \mathrm{C}$. (b) The density of aluminum is $2.70 \mathrm{~g} / \mathrm{cm}^3$ at $25^{\circ} \mathrm{C}$. What is the weight of the aluminum foil with an area of $0.5 \mathrm{~m}^2$ and a

Nicole Wood

Numerade Educator

Problem 37

(a) To identify a liquid substance, a student determined its density. Using a graduated cylinder, she measured out a $45-\mathrm{mL}$. sample of the substance. She then measured the mass of the sample, finding that it weighed $38.5 \mathrm{~g}$. She knew that the substance had to be either isopropyl alcohol (density $0.785 \mathrm{~g} / \mathrm{mL}$ ) or toluene (density $0.866 \mathrm{~g} / \mathrm{mL}$ ). What are the calculated density and the probable identity of the substance? (b) An experiment requires $45.0 \mathrm{~g}$ of ethylene glycol, a liquid whose density is $1.114 \mathrm{~g} / \mathrm{mL}$. Rather than weigh the sample on a balance, a chemist chooses to dispense the liquid using a graduated cylinder. What volume of the liquid should he use? (c) Is a graduated cylinder such as that shown in Figure 1.21 likely to afford the accuracy of measurement needed? (d) A cubic piece of metal measures $5.00 \mathrm{~cm}$ on each edge. If the metal is nickel, whose density is $8.90 \mathrm{~g} / \mathrm{cm}^3$, what is the mass of the cube?

Nicole Wood

Numerade Educator

Problem 38

(a) After the label fell off a bottle containing a clear liquid believed to be benzene, a chemist measured the density of the liquid to verify its identity. A $25.0-\mathrm{mL}$ portion of the liquid had a mass of $21.95 \mathrm{~g}$. A chemistry handbook lists the density of benzene at $15^{\circ} \mathrm{C}$ as $0.8787 \mathrm{~g} / \mathrm{mL}$. Is the calculated density in agreement with the tabulated value? (b) An experiment requires $15.0 \mathrm{~g}$ of cyclohexane, whose density at $25^{\circ} \mathrm{C}$ is $0.7781 \mathrm{~g} / \mathrm{mL}$. What volume of cyclohexane should be used? (c) A spherical ball of lead has a diameter of $5.0 \mathrm{~cm}$. What is the mass of the sphere if lead has a density of $11.34 \mathrm{~g} / \mathrm{cm}^3$ ? (The volume of a sphere is $(4 / 3) \pi r^3$, where $r$ is the radius.)

Lottie Adams

Numerade Educator

Problem 39

If on a certain year, an estimated amount of 4 million metric tons ( 1 metric ton $=1000 \mathrm{~kg}$ ) of nitrous oxide $\left(\mathrm{N}_2 \mathrm{O}\right)$ was emitted worldwide due to agricultural activities, express this mass of $\mathrm{N}_2 \mathrm{O}$ in grams without exponential notation, using an appropriate metric prefix.

Zaida Minjares

Numerade Educator

Problem 40

Silicon for computer chips is grown in large cylinders called "boules" that are $300 \mathrm{~mm}$ in diameter and $2 \mathrm{~m}$ in length, as shown. The density of silicon is $2.33 \mathrm{~g} / \mathrm{cm}^3$. Silicon wafers for making integrated circuits are sliced from a $2.0-\mathrm{m}$ boule and are typically $0.75 \mathrm{~mm}$ thick and $300 \mathrm{~mm}$ in diameter.
(a) How many wafers can be cut from a single boule?
(b) What is the mass of a silicon wafer? (The volume of a cylinder is given by $\pi r^2 h$, where $r$ is the radius and $h$ is its height.)
FIGURE CAN'T COPY.

Nicole Wood

Numerade Educator

Problem 41

Use of the British thermal unit (Btu) is common in some types of engineering work. A Btu is the amount of heat required to raise the temperature of $1 \mathrm{lb}$ of water by $1^{\circ} \mathrm{F}$. Calculate the number of joules in a Btu.

David Collins

Numerade Educator

Problem 42

A watt is a measure of power (the rate of energy change) equal to $1 \mathrm{~J} / \mathrm{s}$. (a) Calculate the number of joules in a kilowatt-hour. (b) An adult person radiates heat to the surroundings at about the same rate as a 100 -watt electric incandescent light bulb. What is the total amount of energy in kcal radiated to the surroundings by an adult over a $24 \mathrm{~h}$ period?

Nicole Wood

Numerade Educator

Problem 43

Indicate which of the following are exact numbers: (a) the mass of a $7.5-$ by $12.5-\mathrm{cm}$ index card, (b) the number of grams
in a kilogram, (c) the volume of a cup of Seattle's Best coffee, (d) the number of centimeters in a kilometer, (e) the number of microseconds in a week, (f) the number of pages in this book.

Zaida Minjares

Numerade Educator

Problem 44

Indicate which of the following are exact numbers: (a) the mass of a $945-\mathrm{mL}$ can of coffee, (b) the number of students in your chemistry class, (c) the temperature of the surface of the Sun, (d) the mass of a postage stamp, (e) the number of milliliters in a cubic meter of water, (f) the average height of NBA basketball players.

Zaida Minjares

Numerade Educator

Problem 45

What is the number of significant figures in each of the following measured quantities? (a) $902.5 \mathrm{~kg}$, (b) $3 \times 10^{-6} \mathrm{~m}$, (c) $0.0096 \mathrm{~L}$, , (d) $2.94 \times 10^3 \mathrm{~m}^2$, (e) $92.03 \mathrm{~km}$ (f) $782.234 \mathrm{~g}$.

Zaida Minjares

Numerade Educator

Problem 46

Indicate the number of significant figures in each of the following measured quantities: (a) $62.65 \mathrm{~km} / \mathrm{hr}$, (b) $78.00 \mathrm{~K}$, (c) $36.9 \mathrm{~mL}$, (d) $250 \mathrm{~mm}$, (e) 89.2 metric tons, (f) $6.4224 \times 10^2 \mathrm{~m}^3$.

Zaida Minjares

Numerade Educator

Problem 47

Round each of the following numbers to three significant figures and express the result in standard exponential notation: (a) 2048732.23 (b) 0.000292945 (c) -82454.09 (d) $942.057024($ e) -0.00000324683 .

Zaida Minjares

Numerade Educator

Problem 48

(a) The diameter of Earth at the equator is $12756.27 \mathrm{~km}$. Round this number to three significant figures and express it in standard exponential notation. (b) The circumference of Earth through the poles is $40,008 \mathrm{~km}$. Round this number to four significant figures and express it in standard exponential notation.

Keenan Mintz

University of Miami

Problem 49

Carry out the following operations and express the answers with the appropriate number of significant numbers.
(a) $43.029+0.02348$
(b) $952.72-73.4201$
(c) $\left(2.93 \times 10^3\right)(0.732)$
(d) $0.06324 / 0.624$

Ronald Prasad

Numerade Educator

Problem 50

Carry out the following operations and express the answers with the appropriate number of significant numbers.
(a) $(6.234+8.72) \times 0.6746$
(b) $732.1-(892.5 / 8.2)$
(c) $\left[\left(3.696 \times 10^5\right)-\left(6.234 \times 10^3\right)\right] \times 0.0742$
(d) $0.006438 \times 108-(8.639+8.52)$

Lottie Adams

Numerade Educator

Problem 51

You weigh an object on a balance and read the mass in grams according to the picture. How many significant figures are in this measurement?

Mercedes Mazza

Numerade Educator

Problem 52

You have a graduated cylinder that contains a liquid (see photograph). Write the volume of the liquid, in milliliters, using the proper number of significant figures.
FIGURE CAN'T COPY.

Ivan Kochetkov

Numerade Educator

Problem 53

Using your knowledge of metric units, English units, and the information on the back inside cover, write down the conversion factors needed to convert (a) in. to $\mathrm{cm}$ (b) $\mathrm{lb}$ to $\mathrm{g}$ (c) $\mu \mathrm{g}$ to $\mathrm{g}(\mathbf{d}) \mathrm{ft}^2$ to $\mathrm{cm}^2$.

Zaida Minjares

Numerade Educator

Problem 54

Using your knowledge of metric units, English units, and the information on the back inside cover, write down the conversion factors needed to convert (a) $\mathrm{km} / \mathrm{hr}$ to $\mathrm{m} / \mathrm{s}$ (b) $\mathrm{mL}$ to $\mu \mathrm{L}$ (c) ps to $\mathrm{s}$ (d) $\mathrm{m}^3$ to gal.

Lottie Adams

Numerade Educator

Problem 55

(a) A bumblebee flies with a ground speed of $15.2 \mathrm{~m} / \mathrm{s}$. Calculate its speed in $\mathrm{km} / \mathrm{hr}$. (b) The lung capacity of the blue whale is $5.0 \times 10^3 \mathrm{~L}$. Convert this volume into gallons. (c) The Statue of Liberty is $151 \mathrm{ft}$ tall. Calculate its height in meters. (d) Bamboo can grow up to $60.0 \mathrm{~cm} /$ day. Convert this growth rate into inches per hour.

Alyssa Hull

Numerade Educator

Problem 56

(a) The speed of light in a vacuum is $2.998 \times 10^8 \mathrm{~m} / \mathrm{s}$. Calculate its speed in miles per hour. (b) The Sears Tower in Chicago is $1454 \mathrm{ft}$ tall. Calculate its height in meters. (c) The Vehicle Assembly Building at the Kennedy Space Center in Florida has a volume of $3,666,500 \mathrm{~m}^3$. Convert this volume to liters and express the result in standard exponential notation. (d) An individual suffering from a high cholesterol level in her blood has $242 \mathrm{mg}$ of cholesterol per $100 \mathrm{~mL}$ of blood. If the total blood volume of the individual is $5.2 \mathrm{~L}$, how many grams of total blood cholesterol does the individual's body contain?

Lottie Adams

Numerade Educator

Problem 57

Perform the following conversions: (a) 5.00 days to 5 , (b) $0.0550 \mathrm{mi}$ to $\mathrm{m}$, (c) $$\$ 1.89$$ $/ \mathrm{gal}$ to dollars per liter, (d) $0.510 \mathrm{in} . / \mathrm{ms}$ to $\mathrm{km} / \mathrm{hr}$, (e) $22.50 \mathrm{gal} / \mathrm{min}$ to $\mathrm{L} / \mathrm{s}$, (f) $0.02500 \mathrm{ft}^3$ to $\mathrm{cm}^3$.

Susan Hallstrom

Susan Hallstrom

Numerade Educator

Problem 58

Carry out the following conversions: (a) $0.105 \mathrm{in}$. to $\mathrm{mm}$, (b) $0.650 \mathrm{qt}$ to $\mathrm{mL}$, (c) $8.75 \mu \mathrm{m} / \mathrm{s}$ to $\mathrm{km} / \mathrm{hr}$, (d) $1.955 \mathrm{~m}^3$ to $\mathrm{yd}^3$ (e) $$\$ 3.99 / \mathrm{lb}$$ to dollars per $\mathrm{kg}$, (f) $8.75 \mathrm{lb} / \mathrm{ft}^3$ to $\mathrm{g} / \mathrm{mL}$.

Lottie Adams

Numerade Educator

Problem 59

(a) How many liters of wine can be held in a wine barrel whose capacity is 31 gal? (b) The recommended adult dose of Elixophyllin ${ }^*$, a drug used to treat asthma, is $6 \mathrm{mg} / \mathrm{kg}$ of body mass. Calculate the dose in milligrams for a $185-\mathrm{lb}$ person. (c) It an automobile is able to travel $400 \mathrm{~km}$ on $4 / .3 \mathrm{~L}$. of gasoline, what is the gas mileage in miles per gallon? (d) When the coffee is brewed according to directions, a pound of coffee beans yields 50 cups of coffee ( 4 cups $=1 \mathrm{qt}$ ). How many $\mathrm{kg}$ of coffee are required to produce 200 cups of coffee?

Allison Krajewski

Allison Krajewski

Numerade Educator

Problem 60

(a) If an electric car is capable of going $225 \mathrm{~km}$ on a single charge, how many charges will it need to travel from Seattle, Washington, to San Diego, California, a distance of $1257 \mathrm{mi}$, assuming that the trip begins with a full charge? (b) If a migrating loon flies at an average speed of $14 \mathrm{~m} / \mathrm{s}$, what is its average speed in $\mathrm{mi} / \mathrm{hr}$ ? (c) What is the engine piston displacement in liters of an engine whose displacement is listed as 450 in. $^3$ ? (d) InMarch 1989 , the Exxon Valdezranagroundand spilled 240,000 barrels of crude petroleum off the coast of Alaska. One barrel of petroleum is equal to 42 gal. How many liters of petroleum were spilled?

Nicole Wood

Numerade Educator

Problem 61

The density of air at ordinary atmospheric pressure and $25^{\circ} \mathrm{C}$ is $1.19 \mathrm{~g} / \mathrm{L}$. What is the mass, in kilograms, of the air in a room that measures $4.5 \mathrm{~m} \times 5.0 \mathrm{~m} \times 2.5 \mathrm{~m}$ ?

Zaida Minjares

Numerade Educator

Problem 62

The indoor concentration of ozone above $300 \mu \mathrm{g} / \mathrm{m}^3$ is considered to be unhealthy. What mass of ozone in grams is present in a room measuring $3.2 \mathrm{~m} \times 2.8 \mathrm{~m} \times 4.1 \mathrm{~m}$ ?

Nicole Wood

Numerade Educator

Problem 63

Gold can be hammered into extremely thin sheets called gold leaf. An architect wants to cover a $30 \mathrm{~m} \times 25 \mathrm{~m}$ ceiling with gold leaf that is twelve-millionths of a centimeter thick. The density of gold is $19.32 \mathrm{~g} / \mathrm{cm}^3$, and gold costs $$\$ 1654$$ per troy ounce ( 1 troy ounce $=31.1034768 \mathrm{~g}$ ). How much will it cost the architect to buy the necessary gold?

Zaida Minjares

Numerade Educator

Problem 64

A copper refinery produces a copper ingot weighing $70 \mathrm{~kg}$. If the copper is drawn into wire whose diameter is $7.50 \mathrm{~mm}$, how many meters of copper can be obtained from the ingot? The density of copper is $8.94 \mathrm{~g} / \mathrm{cm}^3$. (Assume that the wire is a cylinder whose volume $V=\pi r^2 h$, where $r$ is its radius and $h$ is its height or length.)

Lottie Adams

Numerade Educator

Problem 65

Classify each of the following as a pure substance, a solution, or a heterogeneous mixture: (a) a leaf, (b) a 999 gold bar, (c) stainless steel.

Zaida Minjares

Numerade Educator

Problem 66

(a) Which is more likely to eventually be shown to be incorrect: an hypothesis or a theory? (b) A(n) _________ reliably predicts the behavior of matter, while a(n) _____________ provides an explanation for that behavior.

Keenan Mintz

University of Miami

Problem 67

A sample of ascorbic acid (vitamin C) is synthesized in the laboratory. It contains $1.50 \mathrm{~g}$ of carbon and $2.00 \mathrm{~g}$ of oxygen. Another sample of ascorbic acid isolated from citrus fruits contains $6.35 \mathrm{~g}$ of carbon. According to the law of constant composition, how many grams of oxygen does it contain?

Mercedes Mazza

Numerade Educator

Problem 68

Ethyl chloride is sold as a liquid (see photo) under pressure for use as a local skin anesthetic. Ethyl chloride boils at $12{ }^{\circ} \mathrm{C}$ at atmospheric pressure. When the liquid is sprayed onto the skin, it boils off, cooling and numbing the skin as it vaporizes. (a) What changes of state are involved in this use of ethyl chloride? (b) What is the boiling point of ethyl chloride in degrees Fahrenheit? (c) The bottle shown contains $103.5 \mathrm{~mL}$ of ethyl chloride. The density of ethyl chloride at $25^{\circ} \mathrm{C}$ is $0.765 \mathrm{~g} / \mathrm{cm}^3$. What is the mass of ethyl chloride in the bottle?
FIGURE CAN'T COPY.

Keenan Mintz

University of Miami

Problem 69

Two students determine the percentage of lead in a sample as a laboratory exercise. The true percentage is $22.52 \%$. The students' results for three determinations are as follows:
(1) $22.52,22.48,22.54$
(2) $22.64,22.58,22.62$
(a) Calculate the average percentage for each set of data and state which set is the more accurate based on the average.
(b) Precision can be judged by examining the average of the deviations from the average value for that data set. (Calculate the average value for each data set; then calculate the average value of the absolute deviations of each measurement from the average.) Which set is more precise?

Mercedes Mazza

Numerade Educator

Problem 70

Is the use of significant figures in each of the following statements appropriate? (a) The 2005 circulation of National Geographic was 7,812,564. (b) On July 1, 2005, the population of Cook County, Illinois, was 5,303,683. (c) In the United States, $0.621 \%$ of the population has the surname Brown. (d) You calculate your grade point average to be 3.87562.

Zaida Minjares

Numerade Educator

Problem 71

What type of quantity (for example, length, volume, density) do the following units indicate? (a) $\mathrm{m}^3$, (b) $\mathrm{ns}$, (c) $\mathrm{mm},(\mathbf{d}) \mathrm{g} / \mathrm{dm}^3,(\mathbf{e}){ }^{\circ} \mathrm{C},(\mathbf{f}) \mathrm{ms}^{-1}$, (g) Pa.

Zaida Minjares

Numerade Educator

Problem 72

Give the derived SI units for each of the following quantities in base SI units:
(a) acceleration $=$ distance/time ${ }^2$
(b) force $=$ mass $\times$ acceleration
(c) work $=$ force $\times$ distance
(d) pressure $=$ force $/$ area
(e) power = work/time
(f) velocity $=$ distance $/$ time
(g) energy $=$ mass $\times(\text { velocity })^2$

Lottie Adams

Numerade Educator

Problem 73

The distance from Earth to the Moon is approximately $240,000 \mathrm{mi}$. (a) What is this distance in meters? (b) The peregrine falcon has been measured as traveling up to $350 \mathrm{~km} /$ $\mathrm{hr}$ in a dive. If this falcon could fly to the Moon at this speed, how many seconds would it take? (c) The speed of light is $3.00 \times 10^8 \mathrm{~m} / \mathrm{s}$. How long does it take for light to travel from Earth to the Moon and back again? (d) Earth travels around the Sun at an average speed of $29.783 \mathrm{~km} / \mathrm{s}$. Convert this speed to miles per hour.

Lottie Adams

Numerade Educator

Problem 74

Which of the following would you characterize as pure or nearly pure substance? (a) stomach acid; (b) dry ice; (c) ice-cream; (d) stainless steel; (e) petroleum; (f) distilled water; (g) carbon monoxide gas; (h) compressed air in balloon.

Zaida Minjares

Numerade Educator

Problem 75

The U.S. quarter has a mass of $5.67 \mathrm{~g}$ and is approximately $1.55 \mathrm{~mm}$ thick. (a) How many quarters would have to be stacked to reach $575 \mathrm{ft}$, the height of the Washington Monument? (b) How much would this stack weigh? (c) How much money would this stack contain? (d) The U.S. National Debt Clock showed the outstanding public debt to be $$\$ 16,213,166,914,811$$ on October 28,2012 . How many stacks like the one described would be necessary to pay off this debt?

Mercedes Mazza

Numerade Educator

Problem 76

In the United States, water used for irrigation is measured in acre-feet. An acre-foot of water covers an acre to a depth of exactly $1 \mathrm{ft}$. An acre is $4840 \mathrm{yd}^2$. An acre-foot is enough water to supply two typical households for $1.00 \mathrm{yr}$. (a) If desalinated water costs $$\$ 1950$$ per acre-foot, how much does desalinated water cost per liter? (b) How much would it cost one household per day if it were the only source of water?

Lottie Adams

Numerade Educator

Problem 77

By using estimation technique, determine which of the following is the heaviest and which is the lightest: a $10-\mathrm{lb}$ bag of fertilizer, a $10-\mathrm{kg}$ bag of rice, or 2 gal of olive oil (density $=0.918 \mathrm{~g} / \mathrm{cm}^3$ ).

Nicole Wood

Numerade Educator

Problem 78

Suppose you decide to define your own temperature scale with units of $\mathrm{O}$, using the freezing point $\left(13^{\circ} \mathrm{C}\right)$ and boiling point $\left(360^{\circ} \mathrm{C}\right)$ of oleic acid, the main component of olive oil. If you set the freezing point of oleic acid as $0^{\circ} \mathrm{O}$ and the boiling point as $100^{\circ} \mathrm{O}$, what is the freezing point of water on this new scale?

Keenan Mintz

University of Miami

Problem 79

Hexane (density $=0.659 \mathrm{~g} / \mathrm{mL}$ ) and acetic acid (density $=$ $1.0446 \mathrm{~g} / \mathrm{mL}$ ) do not form a solution when mixed but are separate in distinct layers. A piece of oak wood (density $=900 \mathrm{~kg} / \mathrm{m}^3$ ) is placed inside a test tube containing hexane and acetic acid solution; sketch how the three substances would position themselves.

Ronald Prasad

Numerade Educator

Problem 80

Two spheres of equal volume are placed on the scales as shown. Which one is more dense?

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 81

Water has a density of $0.997 \mathrm{~g} / \mathrm{cm}^3$ at $25^{\circ} \mathrm{C}$; ice has a density of $0.917 \mathrm{~g} / \mathrm{cm}^3$ at $-10^{\circ} \mathrm{C}$. (a) If a soft-drink bottle whose volume is $1.50 \mathrm{~L}$ is completely filled with water and then frozen to $-10^{\circ} \mathrm{C}$, what volume does the ice occupy? (b) Can the ice be contained within the bottle?
FIGURE CAN'T COPY.

Mercedes Mazza

Numerade Educator

Problem 82

A $32.65-\mathrm{g}$ sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the total volume of solid and liquid together is $50.00 \mathrm{~mL}$. The solid and toluene together weigh $58.58 \mathrm{~g}$. The density of toluene at the temperature of the experiment is $0.864 \mathrm{~g} / \mathrm{mL}$. What is the density of the solid?

Keenan Mintz

University of Miami

Problem 83

A thief plans to steal a cylindrical platinum medal with a radius of $2.3 \mathrm{~cm}$ and a thickness of $0.8 \mathrm{~cm}$ from a jewellery store. If the platinum has a density of $21.45 \mathrm{~g} / \mathrm{cm}^3$, what is the mass of the medal in $\mathrm{kg}$ ? [The volume of a cylinder is $V=\pi r^2 h$.]

Nicole Wood

Numerade Educator

Problem 84

Saline solution used in hospital contains $0.9 \%$ sodium chloride by mass. Calculate the number of grams of sodium chloride in 0.5 gal of saline solution if the solution has a density of $1.01 \mathrm{~g} / \mathrm{mL}$.

Nicole Wood

Numerade Educator

Problem 85

A 40-lb container of peat moss measures $14 \times 20 \times 30 \mathrm{in}$. A $40-\mathrm{lb}$ container of topsoil has a volume of $1.9 \mathrm{gal}$. (a) Calculate the average densities of peat moss and topsoil in units of $\mathrm{g} / \mathrm{cm}^3$. Would it be correct to say that peat moss is "lighter" than topsoil? (b) How many bags of peat moss are needed to cover an area measuring $15.0 \mathrm{ft} \times 20.0 \mathrm{ft}$ to a depth of $3.0 \mathrm{in}$.?

Lottie Adams

Numerade Educator

Problem 86

A $10.0 \mathrm{~g}$ block of gold is hammered into a thin gold sheet which has an area of $150 \mathrm{~cm}^2$. Given the density of gold is $19.3 \mathrm{~g} / \mathrm{cm}^3$, what is the approximate thickness of the gold sheet in millimeters?

David Collins

Numerade Educator

Problem 87

The total rate at which power is used by humans worldwide is approximately 15 TW (terawatts). The solar flux averaged over the sunlit half of Earth is $680 \mathrm{~W} / \mathrm{m}^2$ (assuming no clouds). The area of Earth's disc as seen from the Sun is $1.28 \times 10^{14} \mathrm{~m}^2$. The surface area of Earth is approximately $197,000,000$ square miles. How much of Earth's surface would we need to cover with solar energy collectors to power the planet for use by all humans? Assume that the solar energy collectors can convert only $10 \%$ of the available sunlight into useful power.

Ronald Prasad

Numerade Educator

Problem 88

In 2005, J. Robin Warren and Barry J. Marshall shared the Nobel Prize in Medicine for discovering the bacterium Helicobacter pylori and for establishing experimental proof that it plays a major role in gastritis and peptic ulcer disease. The story began when Warren, a pathologist, noticed that bacilli were associated with the tissues taken from patients suffering from ulcers. Look up the history of this case and describe Warren's first hypothesis. What sorts of evidence did it take to create a credible theory based on it?

Keenan Mintz

University of Miami

Problem 89

A $30.0-\mathrm{cm}-$ long cylindrical plastic tube, sealed at one end, is filled with acetic acid. The mass of acetic acid needed to fill the tube is found to be $89.24 \mathrm{~g}$. The density of acetic acid is $1.05 \mathrm{~g} / \mathrm{mL}$. Calculate the inner diameter of the tube in centimeters.

Zaida Minjares

Numerade Educator

Problem 90

Gold is alloyed (mixed) with other metals to increase its hardness in making jewelry. (a) Consider a piece of gold jewelry that weighs $9.85 \mathrm{~g}$ and has a volume of $0.675 \mathrm{~cm}^3$. The jewelry contains only gold and silver, which have densities of 19.3 and $10.5 \mathrm{~g} / \mathrm{cm}^3$, respectively. If the total volume of the jewelry is the sum of the volumes of the gold and silver that it contains, calculate the percentage of gold (by mass) in the jewelry. (b) The relative amount of gold in an alloy is commonly expressed in units of carats. Pure gold is 24 carat, and the percentage of gold in an alloy is given as a percentage of this value. For example, an alloy that is $50 \%$ gold is 12 carat. State the purity of the gold jewelry in carats.

Susan Hallstrom

Susan Hallstrom

Numerade Educator

Problem 91

Paper chromatography is a simple but reliable method for separating a mixture into its constituent substances. You have a mixture of two vegetable dyes, one red and one blue, that you are trying to separate. You try two different chromatography procedures and achieve the separations shown in the figure. Which procedure worked better? Can you suggest a method to quantify how good or poor the separation was?
FIGURE CAN'T COPY.

Mercedes Mazza

Numerade Educator

Problem 92

Judge the following statements as true or false. If you believe a statement to be false, provide a corrected version.
(a) Air and water are both elements.
(b) All mixtures contain at least one element and one compound.
(c) Compounds can be decomposed into two or more other substances; elements cannot.
(d) Elements can exist in any of the three states of matter.
(e) When yellow stains in a kitchen sink are treated with bleach water, the disappearance of the stains is due to a physical change.
(f) A hypothesis is more weakly supported by experimental evidence than a theory.
(g) The number 0.0033 has more significant figures than 0.033 .
(h) Conversion factors used in converting units always have a numerical value of one.
(i) Compounds always contain at least two different elements.

Keenan Mintz

University of Miami

Problem 93

You are assigned the task of separating a desired granular material with a density of $3.62 \mathrm{~g} / \mathrm{cm}^3$ from an undesired granular material that has a density of $2.04 \mathrm{~g} / \mathrm{cm}^3$. You want to do this by shaking the mixture in a liquid in which the heavier material will fall to the bottom and the lighter material will float. A solid will float on any liquid that is more dense. Using an Internet-based source or a handbook of chemistry, find the densities of the following substances: carbon tetrachloride, hexane, benzene, and diiodomethane. Which of these liquids will serve your purpose, assuming no chemical interaction takes place between the liquid and the solids?

Lottie Adams

Numerade Educator

Problem 94

In 2009 , a team from Northwestern University and Western Washington University reported the preparation of a new "spongy" material composed of nickel, molybdenum, and sulfur that excels at removing mercury from water. The density of this new material is $0.20 \mathrm{~g} / \mathrm{cm}^3$, and its surface area is $1242 \mathrm{~m}^2$ per gram of material. (a) Calculate the volume of a 10.0 -mg sample of this material. (b) Calculate the surface area for a $10.0-\mathrm{mg}$ sample of this material. (c) A $10.0-\mathrm{mL}$. sample of contaminated water had $7.748 \mathrm{mg}$ of mercury in it. After treatment with $10.0 \mathrm{mg}$ of the new spongy material, $0.001 \mathrm{mg}$ of mercury remained in the contaminated water. What percentage of the mercury was removed from the water? (d) What is the final mass of the spongy material after the exposure to mercury?

Keenan Mintz

University of Miami