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Foundations of College Chemistry

Morris Hein, Susan Arena, Cary Willard

Chapter 2

Standards for Measurement - all with Video Answers

Educators

Chapter Questions

02:17

Problem 1

What is the numerical meaning of each of the following?
(a) kilogram
(b) centimeter
(c) microliter
(d) millimeter
(e) deciliter

Ethan Fuhrman
Ethan Fuhrman
Numerade Educator
01:42

Problem 2

What is the correct unit of measurement for each of the following?
(a) $1000 \mathrm{~m}$
(b) $0.1 \mathrm{~g}$
(c) $0.000001 \mathrm{~L}$
(d) $0.01 \mathrm{~m}$
(e) $0.001 \mathrm{~L}$

John Nicolle
John Nicolle
Numerade Educator
01:00

Problem 3

State the abbreviation for each of the following units:
(a) gram
(b) microgram
(c) centimeter
(d) micrometer
(e) milliliter
(f) deciliter

John Nicolle
John Nicolle
Numerade Educator
01:00

Problem 4

State the abbreviation for each of the following units:
(a) milligram
(b) kilogram
(c) meter
(d) nanometer
(e) angstrom
(f) microliter

John Nicolle
John Nicolle
Numerade Educator
00:47

Problem 5

. Determine whether the zeros in each number are significant:
(a) 2050
(b) $9.00 \times 10^{2}$
(c) $0.0530$
(d) $0.075$
(e) 300 .
(f) $285.00$

Emily Himsel
Emily Himsel
Numerade Educator
02:38

Problem 6

Determine whether the zeros in each number are significant:
(a) $0.005$
(b) 1500
(c) 250 .
(d) $10.000$
(e) $6.070 \times 10^{4}$
(f) $0.2300$

Dr. Satish Ingale
Dr. Satish Ingale
Numerade Educator
02:23

Problem 7

How many significant figures are in each of the following numbers?
(a) $0.025$
(b) $22.4$
(c) $0.0404$
(d) $5.50 \times 10^{3}$

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
03:00

Problem 8

State the number of significant figures in each of the following numbers:
(a) $40.0$
(b) $0.081$
(c) 129,042
(d) $4.090 \times 10^{-3}$

Amit Srivastava
Amit Srivastava
Numerade Educator
01:51

Problem 9

Round each of the following numbers to three significant figures:
(a) $93.246$
(b) $0.02857$
(c) $4.644$
(d) $34.250$

Kim Trang Nguyen
Kim Trang Nguyen
Numerade Educator
04:00

Problem 10

Round each of the following numbers to three significant figures:
(a) $8.8726$
(b) $21.25$
(c) $129.509$
(d) $1.995 \times 10^{6}$

Kim Trang Nguyen
Kim Trang Nguyen
Numerade Educator
01:40

Problem 11

Express each of the following numbers in exponential notation:
(a) $2,900,000$
(b) $0.587$
(c) $0.00840$
(d) $0.0000055$

Kim Trang Nguyen
Kim Trang Nguyen
Numerade Educator
01:45

Problem 12

Write each of the following numbers in exponential notation:
(a) $0.0456$
(b) $4082.2$
(c) $40.30$
(d) $12,000,000$

Ma Ednelyn Lim
Ma Ednelyn Lim
Numerade Educator
02:05

Problem 13

Solve the following problems, stating answers to the proper number of significant figures:
(a) $12.62+1.5+0.25=$ ?
(b) $\left(2.25 \times 10^{3}\right)\left(4.80 \times 10^{4}\right)=$ ?
(c) $\frac{(452)(6.2)}{14.3}=$ ?
(d) $(0.0394)(12.8)=$ ?
(e) $\frac{0.4278}{59.6}=$ ?
(f) $10.4+3.75\left(1.5 \times 10^{4}\right)=$ ?

Crystal Wang
Crystal Wang
Numerade Educator
01:33

Problem 14

Evaluate each of the following expressions. State the answer to the proper number of significant figures:
(a) $15.2-2.75+15.67$
(b) $(4.68)(12.5)$
(c) $\frac{182.6}{4.6}$
(d) $1986+23.84+0.012$
(e) $\frac{29.3}{(284)(415)}$

Dr. Satish Ingale
Dr. Satish Ingale
Numerade Educator
04:09

Problem 15

Change these fractions into decimals. Express each answer to three significant figures:
(a) $\frac{5}{6}$
(b) $\frac{3}{7}$
(c) $\frac{12}{16}$
(d) $\frac{9}{18}$

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
01:36

Problem 16

Change each of the following decimals to fractions in lowest terms:
(a) $0.25$
(b) $0.625$
(c) $1.67$
(d) $0.8888$

Mir Afzal
Mir Afzal
Numerade Educator
03:20

Problem 17

Solve each of these equations for $x$ :
(a) $3.42 x=6.5$
(b) $\frac{x}{12.3}=7.05$
(c) $\frac{0.525}{x}=0.25$

Allison Knapp
Allison Knapp
Numerade Educator
02:49

Problem 18

Solve each equation for the variable:
(a) $x=\frac{212-32}{1.8}$
(b) $8.9 \frac{\mathrm{g}}{\mathrm{mL}}=\frac{40.90 \mathrm{~g}}{x}$
(c) $72^{\circ} \mathrm{F}=1.8 x+32$

Allison Knapp
Allison Knapp
Numerade Educator
09:09

Problem 19

Complete the following metric conversions using the correct number of significant figures:
(a) $28.0 \mathrm{~cm}$ to $\mathrm{m}$
(b) $1000 \mathrm{~m}$ to $\mathrm{km}$
(c) $9.28 \mathrm{~cm}$ to $\mathrm{mm}$
(d) $10.68 \mathrm{~g}$ to $\mathrm{mg}$
(e) $6.8 \times 10^{4} \mathrm{mg}$ to $\mathrm{kg}$
(f) $8.54 \mathrm{~g}$ to $\mathrm{kg}$
(g) $25.0 \mathrm{~mL}$ to $\mathrm{L}$
(h) $22.4 \mathrm{~L}$ to $\mu \mathrm{L}$

Stephen Mull
Stephen Mull
Numerade Educator
09:09

Problem 20

Complete the following metric conversions using the correct number of significant figures:
(a) $4.5 \mathrm{~cm}$ to $\hat{\mathrm{A}}$
(b) $12 \mathrm{~nm}$ to $\mathrm{cm}$
(c) $8.0 \mathrm{~km}$ to $\mathrm{mm}$
(d) $164 \mathrm{mg}$ to $\mathrm{g}$
(e) $0.65 \mathrm{~kg}$ to $\mathrm{mg}$
(f) $5.5 \mathrm{~kg}$ to g
(g) $0.468 \mathrm{~L}$ to $\mathrm{mL}$
(h) $9.0 \mu \mathrm{L}$ to $\mathrm{mL}$

Stephen Mull
Stephen Mull
Numerade Educator
09:09

Problem 21

Complete the following U.S./metric conversions using the correct number of significant figures:
(a) $42.2$ in. to $\mathrm{cm}$
(b) $0.64 \mathrm{~m}$ to in.
(c) $2.00 \mathrm{in}^{2}$ to $\mathrm{cm}^{2}$
(d) $42.8 \mathrm{~kg}$ to $\mathrm{lb}$
(e) $3.5 \mathrm{qt}$ to $\mathrm{mL}$
(f) $20.0 \mathrm{~L}$ to gal

Stephen Mull
Stephen Mull
Numerade Educator
09:09

Problem 22

Make the following conversions using the correct number of significant figures:
(a) $35.6 \mathrm{~m}$ to $\mathrm{ft}$
(b) $16.5 \mathrm{~km}$ to mi
(c) $4.5 \mathrm{in}^{3}$ to $\mathrm{mm}^{3}$
(d) $95 \mathrm{lb}$ to $\mathrm{g}$
(e) $20.0 \mathrm{gal}$ to $\mathrm{L}$
(f) $4.5 \times 10^{4} \mathrm{ft}^{3}$ to $\mathrm{m}^{3}$

Stephen Mull
Stephen Mull
Numerade Educator
02:15

Problem 23

After you have worked out at the gym on a stationary bike for $45 \mathrm{~min}$, the distance gauge indicates that you have traveled $15.2 \mathrm{mi}$. What was your rate in $\mathrm{km} / \mathrm{hr}$ ?

Alex Ryder
Alex Ryder
Numerade Educator
00:31

Problem 24

A competitive college runner ran a $5-\mathrm{K}(5.0-\mathrm{km})$ race in $15 \mathrm{~min}$, $23 \mathrm{~s}$. What was her pace in miles per hour?

Donald Albin
Donald Albin
Numerade Educator
03:38

Problem 25

A pharmacy technician is asked to prepare an antibiotic IV solution that will contain 500. mg of cephalosporin for every 100 . $\mathrm{mL}$ of normal saline solution. The total volume of saline solution will be 1 L. How many grams of the cephalosporin will be needed for this IV solution?

Dr. Satish Ingale
Dr. Satish Ingale
Numerade Educator
02:09

Problem 26

An extra-strength aspirin tablet contains $0.500 \mathrm{~g}$ of the active ingredient, acetylsalicylic acid. Aspirin strength used to be measured in grains. If 1 grain $=60 \mathrm{mg}$, how many grains of the active ingredient are in 1 tablet? (Report your answer to three significant figures.)

Ramesh Singh
Ramesh Singh
Numerade Educator
04:01

Problem 27

The maximum speed recorded for a giant tortoise is $0.11 \mathrm{~m} / \mathrm{sec}$. How many miles could a gaint tortoise travel in $5.0 \mathrm{hr}$ ?

Chris Trentman
Chris Trentman
Numerade Educator
04:41

Problem 28

How many days would it take for a crepe myrtle tree to grow 1 $\mathrm{cm}$ in height if it grows $3.38$ feet per year? (Report your answer to three significant figures)

Alanya Huang
Alanya Huang
Numerade Educator
01:04

Problem 29

A giant anteater is able to eat $6.7 \mathrm{lb}$ of ants in a day. If an ant has a mass of $85 \mathrm{mg}$, how many ants does the giant anteater eat in a day?

Daniel Lai
Daniel Lai
Numerade Educator
01:50

Problem 30

A large egg has an average mass of $58.5 \mathrm{~g}$. If a recipe calls for $0.75 \mathrm{lb}$ of eggs, how many large eggs should be added to the mix?

Teresa Fuston
Teresa Fuston
Numerade Educator
02:04

Problem 31

A personal trainer uses calipers on a client to determine his percent body fat. After taking the necessary measurements, the personal trainer determines that the client's body contains $11.2 \%$ fat by mass ( $11.2 \mathrm{lb}$ of fat per $100 \mathrm{lb}$ of body mass). If the client weighs $225 \mathrm{lb}$, how many $\mathrm{kg}$ of fat does he have?

Leif Engstrom
Leif Engstrom
Numerade Educator
02:38

Problem 32

The weight of a diamond is measured in carats. How many pounds does a $5.75$-carat diamond weigh? ( 1 carat $=200$. mg)

Arron Martel
Arron Martel
Numerade Educator
05:20

Problem 33

A competitive high school swimmer takes $52 \mathrm{~s}$ to swim 100 . yards. What is his rate in $\mathrm{m} / \mathrm{min}$ ?

Alex Bretton
Alex Bretton
Numerade Educator
01:15

Problem 34

In 2005 , Jarno Trulli was the pole winner of the U.S. Grand Prix Race with a speed of $133 \mathrm{mi}$ per hr. What was his speed in $\mathrm{cm} / \mathrm{s}$ ?

Shahab Ullah
Shahab Ullah
Numerade Educator
04:04

Problem 35

In 2006, Christian Stengl climbed to the top of Mount Everest, elevation $29,035 \mathrm{ft}$, from a starting point of $21,002 \mathrm{ft}$ in a record time of $16 \mathrm{hr}, 42 \mathrm{~min}$. Determine his average rate of climb in
(a) miles per minute
(b) meters per second

Kian Manafi
Kian Manafi
Numerade Educator
01:36

Problem 36

The Alvin, a submersible research vessel, can descend into the ocean to a depth of approximately $4500 \mathrm{~m}$ in just over $5 \mathrm{hr}$. Determine its average rate of submersion in
(a) feet per minute
(b) kilometers per second

Joshua Fischbach
Joshua Fischbach
Numerade Educator
02:11

Problem 37

The 2013 Rolls Royce Ghost Alpine has a top speed of 155 miles per hour. Calculate the speed in centimeters per second.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
02:04

Problem 38

The 2014 Tesla Roadster, an all-electric car, has a top speed of 125 miles per hour. Calculate the speed in centimeters per second.

Laszlo Zalavari
Laszlo Zalavari
Numerade Educator
02:07

Problem 39

The world's record for the largest cup of coffee was broken on October 15, 2010, with a 2010-gal cup of coffee in Las Vegas, Nevada. If a cup of coffee contains $473 \mathrm{~mL}$ of coffee, how many cups of coffee would be required to fill this coffee cup?

Brandon Fox
Brandon Fox
Numerade Educator
08:13

Problem 40

Tilapia is rapidly becoming an important source of fish around the world. This is because it can be farmed easily and sustainably. In 2011,475 million lb of tilapia were consumed by Americans. If the average tilapia has a mass of $535 \mathrm{~g}$, how many tilapia were consumed in 2011 ?

Bobby Barnes
Bobby Barnes
University of North Texas
View

Problem 41

Assuming that there are 20 . drops in $1.0 \mathrm{~mL}$, how many drops are in $1.0$ gallon?

David Morris
David Morris
Numerade Educator
00:47

Problem 42

How many liters of oil are in a 42 -gal barrel of oil?

Ronald Prasad
Ronald Prasad
Numerade Educator
00:26

Problem 43

Calculate the number of milliliters of water in a cubic foot of water.

Ashley Volpe
Ashley Volpe
Numerade Educator
01:58

Problem 44

Oil spreads in a thin layer on water called an "oil slick." How much area in $\mathrm{m}^{2}$ will $200 \mathrm{~cm}^{3}$ of oil cover if it forms a layer $0.5$ nm thick?

Averell Hause
Averell Hause
Carnegie Mellon University
01:43

Problem 45

A textbook is $27 \mathrm{~cm}$ long, $21 \mathrm{~cm}$ wide, and $4.4 \mathrm{~cm}$ thick. What is the volume in:
(a) cubic centimeters?
(b) liters?
(c) cubic inches?

Ren Jie Tuieng
Ren Jie Tuieng
Numerade Educator
01:14

Problem 46

An aquarium measures 16 in. $\times 8$ in. $\times 10$ in. How many liters of water does it hold? How many gallons?

Dalia Fantini
Dalia Fantini
University of Pittsburgh - Main Campus
02:49

Problem 47

Raspberry ketone, used to give food a raspberry or blueberry flavor, is composed of $73.14 \%$ by mass carbon. How many grams of carbon are in a 250 .-g sample of this flavoring?

Himanshu Garg
Himanshu Garg
Numerade Educator
01:34

Problem 48

Nectaryl is a compound with a peachy, apricot-like odor. It is composed of $10.98 \%$ hydrogen. How many grams of hydrogen are in a $475-g$ sample of nectaryl?

Vasu Makani
Vasu Makani
Numerade Educator
03:36

Problem 49

A solution is prepared by dissolving $283.4$ grams of potassium dichromate in $650.0$ grams of water.
(a) What is the percent potassium dichromate in the solution?
(b) If 275 . grams of the solution are poured into a beaker, how many grams of potassium dichromate are introduced into the beaker?
(c) How many grams of the solution are required to obtain $15.0$ grams of potassium dichromate?

Sima Sarker
Sima Sarker
Numerade Educator
07:02

Problem 50

A solution is prepared by dissolving $95.4$ grams of sodium nitrate in 753 grams of water.
(a) What is the percent sodium nitrate in the solution?
(b) If 350 . grams of the solution are poured into a beaker, how many grams of sodium nitrate are introduced into the beaker?
(c) How many grams of the solution are required to obtain $50.0$ grams of sodium nitrate?

Nicole Smina
Nicole Smina
Numerade Educator
05:41

Problem 51

A toddler in Italy visits the family doctor. The nurse takes the child's temperature, which reads $38.8^{\circ} \mathrm{C}$.
(a) Convert this temperature to ${ }^{\circ} \mathrm{F}$.
(b) If $98.6^{\circ} \mathrm{F}$ is considered normal, does the child have a fever?

Dr. Satish Ingale
Dr. Satish Ingale
Numerade Educator
01:01

Problem 52

Driving to the grocery store, you notice the temperature is $45^{\circ} \mathrm{C}$. Determine what this temperature is on the Fahrenheit scale and what season of the year it might be.

Heather Zimmers
Heather Zimmers
Numerade Educator
03:20

Problem 53

Make the following conversions and include an equation for each one:
(a) $162^{\circ} \mathrm{F}$ to ${ }^{\circ} \mathrm{C}$
(b) $0.0^{\circ} \mathrm{F}$ to $\mathrm{K}$
(c) $-18^{\circ} \mathrm{C}$ to ${ }^{\circ} \mathrm{F}$
(d) $212 \mathrm{~K}$ to ${ }^{\circ} \mathrm{C}$

Ronald Prasad
Ronald Prasad
Numerade Educator
03:20

Problem 54

Make the following conversions and include an equation for each one:
(a) $32^{\circ} \mathrm{C}$ to ${ }^{\circ} \mathrm{F}$
(b) $-8.6^{\circ} \mathrm{F}$ to ${ }^{\circ} \mathrm{C}$
(c) $273^{\circ} \mathrm{C}$ to $\mathrm{K}$
(d) $100 \mathrm{~K}$ to ${ }^{\circ} \mathrm{F}$

Ronald Prasad
Ronald Prasad
Numerade Educator
01:14

Problem 55

A recipe calls for heating the oven to $425^{\circ} \mathrm{F}$. If you are vacationing in Europe and the oven only has temperature marked in ${ }^{\circ} \mathrm{C}$, to what temperature do you preheat the oven? What is this temperature in $\mathrm{K}$ ?

Ishita J.
Ishita J.
Numerade Educator
01:14

Problem 56

You borrowed a thermometer from the chemistry lab to use in the kitchen. If you want to heat a mixture of sugar and cream to $247^{\circ} \mathrm{F}$, what temperature do you need in ${ }^{\circ} \mathrm{C}$ ? What is this temperature in $\mathrm{K}$ ?

Ishita J.
Ishita J.
Numerade Educator
01:13

Problem 57

At what temperature are the Fahrenheit and Celsius temperatures exactly equal?

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:13

Problem 58

At what temperature are Fahrenheit and Celsius temperatures the same in value but opposite in sign?

Varsha Aggarwal
Varsha Aggarwal
Numerade Educator
01:00

Problem 59

The average temperature on Venus is $460^{\circ} \mathrm{C}$. What is this temperature in ${ }^{\circ} \mathrm{F}$ ?

Sarah X
Sarah X
Numerade Educator
00:37

Problem 60

The average temperature at the top of Jupiter's clouds is $-244^{\circ} \mathrm{F}$. What is this temperature in ${ }^{\circ} \mathrm{C}$ ?

Emily Himsel
Emily Himsel
Numerade Educator
01:21

Problem 61

What is the density of a sample of $65.0 \mathrm{~mL}$ of automobile oil having a mass of $59.82 \mathrm{~g}$ ?

Ronald Prasad
Ronald Prasad
Numerade Educator
00:40

Problem 62

A $25.2-\mathrm{mL}$ sample of kerosene was determined to have a mass of $20.41 \mathrm{~g}$. What is the density of kerosene?

Ronald Prasad
Ronald Prasad
Numerade Educator
04:16

Problem 63

A student weighed an empty graduated cylinder and found that it had a mass of $25.23 \mathrm{~g}$. When filled with $25.0 \mathrm{~mL}$ of an unknown liquid, the total mass was $50.92 \mathrm{~g}$. What is the density of the liquid?

Vishal Sharma
Vishal Sharma
Numerade Educator
03:59

Problem 64

A total of $32.95 \mathrm{~g}$ of mossy zinc was placed into a graduated cylinder containing $50.0 \mathrm{~mL}$ of water. The water level rose to $54.6 \mathrm{~mL}$. Determine the density of the zinc.

Allison Krajewski
Allison Krajewski
Numerade Educator
00:25

Problem 65

Linseed oil has a density of $0.929 \mathrm{~g} / \mathrm{mL}$. How many $\mathrm{mL}$ are in $15 \mathrm{~g}$ of the oil?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:54

Problem 66

Glycerol has a density of $1.20 \mathrm{~g} / \mathrm{mL}$. How many $\mathrm{mL}$ are in $75 \mathrm{~g}$ of glycerol?

Kim Trang Nguyen
Kim Trang Nguyen
Numerade Educator
01:46

Problem 67

A Mexican restaurant has the reputation of serving the hottest salsa in town. In order to maintain this standard, the restaurant must use a minimum of $8.41 \%$ by mass of cayenne pepper. If the restaurant just received a $3.26-\mathrm{kg}$ shipment of cayenne pepper, how many pounds of salsa can it make?

Heather Zimmers
Heather Zimmers
Numerade Educator
00:59

Problem 68

In a candy factory, the nutty chocolate bars contain $22.0 \%$ by mass of pecans. If $7.0 \mathrm{~kg}$ of pecans were used for candy last Thursday, how many pounds of nutty chocolate bars were made?

AG
Ankit Gupta
Numerade Educator
01:33

Problem 69

U.S. quarters are composed of $91.67 \%$ copper and $8.33 \%$ nickel. The mass of a quarter is $5.670 \mathrm{~g}$.
(a) Write out the dimensional analysis factors that can be derived from the two percentages given above. Be sure to include units.
(b) If the U.S. mint buys $3.0$ tons of copper for making quarters, how many quarters can it make?

Rylie Howey
Rylie Howey
Numerade Educator
07:27

Problem 70

A jewelry maker sells lots of sterling silver hearts with a mass of $35.0 \mathrm{~g}$. Sterling silver is composed of $92.5 \%$ silver and $7.50 \%$ copper.
(a) Write out the dimensional analysis factors that can be derived from the two percentages given above. Be sure to include units.
(b) If the jeweler buys $50.0$ lb of silver to make the hearts, how many sterling silver hearts can the jeweler make?

Mercedes Mazza
Mercedes Mazza
Numerade Educator
01:14

Problem 71

You calculate that you need $10.0123576 \mathrm{~g}$ of $\mathrm{NaCl}$ for an experiment. What amount should you measure out if the precision of the balance is
(a) $+$ or $-0.01 \mathrm{~g}$ ?
(b) $+$ or $-0.001 \mathrm{~g}$ ?
(c) + or $-0.0001 \mathrm{~g}$ ?

Matthew Confer
Matthew Confer
Numerade Educator
01:41

Problem 72

Often small objects are measured by mass in order to count them.
(a) If the mass of 1 Skittle is $1.134 \mathrm{~g}$, what mass of Skittles should be packaged in a bag containing 175 Skittles?
(b) The volume of exactly 6 Skittles is $5.3 \mathrm{~mL}$ as measured in a $10.0-\mathrm{mL}$ graduated cylinder. What volume (in liters) of Skittles should be packaged in a bag containing 175 Skittles?
(c) Determine the number of Skittles expected in a $325.0$-g bag of Skittles.
(d) Determine the number of Skittles expected in a beaker containing $0.550 \mathrm{~L}$ of Skittles.
(e) Five bags were filled with $350.0 \mathrm{~g}$ of Skittles and 5 more bags were filled with $0.325 \mathrm{~L}$ of Skittles. The Skittles in each bag were then counted, and the data are tabulated below:

Ronald Prasad
Ronald Prasad
Numerade Educator
01:43

Problem 73

Suppose you want to add $100 \mathrm{~mL}$ of solvent to a reaction flask. Which piece of glassware shown in Figure $2.4$ would be the best choice for accomplishing this task and why?

Crystal Wang
Crystal Wang
Numerade Educator
00:39

Problem 74

A reaction requires $21.5 \mathrm{~g}$ of $\mathrm{CHCl}_{3}$. No balance is available, so it will have to be measured by volume. How many $\mathrm{mL}$ of $\mathrm{CHCl}_{3}$ need to be taken? (Density of $\mathrm{CHCl}_{3}$ is $1.484 \mathrm{~g} / \mathrm{mL}$.)

David Collins
David Collins
Numerade Educator
02:56

Problem 75

A $25.27$-g sample of pure sodium was prepared for an experiment. How many $\mathrm{mL}$ of sodium is this? (Density of sodium is $0.97 \mathrm{~g} / \mathrm{mL}$.)

Jorge Villanueva
Jorge Villanueva
Numerade Educator
02:10

Problem 76

In the United States, coffee consumption averages $4.00 \times 10^{8}$ cups per day. If each cup of coffee contains $160 \mathrm{mg}$ caffeine, how many pounds of caffeine are being consumed each day?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
03:03

Problem 77

In a role-playing video game (RPG) your character is a Human Paladin that can carry $115 \mathrm{lb}$ of gear. Your character is carrying 92 lb of gear and a vial of strength potion (which allows you to carry an additional $50.0$ lb of gear). If you find a cave filled with mass potions (used for resisting strong winds), after using the strength potion, how many vials can you collect if the vials each contain $50.0 \mathrm{~mL}$ of mass potion with a density of $193 \mathrm{~g} / \mathrm{mL}$ ? The vials have negligible mass.

Angelina Chavez
Angelina Chavez
Numerade Educator
01:49

Problem 78

A cape is designed for Lady Gaga's concert with 4560 sequins. If a sequin has a volume of $0.0241 \mathrm{~cm}^{3}$ and the sequins have a density of $41.6 \mathrm{~g} / \mathrm{cm}^{3}$, what is the mass in $\mathrm{lb}$ and $\mathrm{kg}$ of sequins on Lady Gaga's cape?

Ronald Prasad
Ronald Prasad
Numerade Educator
01:08

Problem 79

Will a hollow cube with sides of length $0.50 \mathrm{~m}$ hold $8.5 \mathrm{~L}$ of solution? Depending on your answer, how much additional solution would be required to fill the container or how many times would the container need to be filled to measure the $8.5 \mathrm{~L}$ ?

Jay Patel
Jay Patel
Numerade Educator
01:38

Problem 80

The accepted toxic dose of mercury is $300 \mu \mathrm{g} /$ day. Dental offices sometimes contain as much as $180 \mu \mathrm{g}$ of mercury per cubic meter of air. If a nurse working in the office ingests $2 \times 10^{4} \mathrm{~L}$ of air per day, is he or she at risk for mercury poisoning?

Himanshu Garg
Himanshu Garg
Numerade Educator
05:13

Problem 81

The city of San Diego used an average of 1380 acre-feet of water per day during January of this year. Given that 1 acrefoot $=1.233 \times 10^{6} \mathrm{~L}$,
(a) Calculate the kL of water used every day.
(b) Calculate the number of gallons of water used by San Diego last January.

Keenan Mintz
Keenan Mintz
University of Miami
01:02

Problem 82

Hydrogen becomes a liquid at $20.27 \mathrm{~K}$. What is this temperature in
(a) ${ }^{\circ} \mathrm{C}$ ?
(b) ${ }^{\circ} \mathrm{F}$ ?

Shashika Bandara
Shashika Bandara
Numerade Educator
02:53

Problem 83

Scientists led by Rob Eagle at CalTech have examined 150 -million-year-old fossilized teeth of sauropods, huge four-legged dinosaurs, to determine their average body temperature. They analyzed the type and number of carbon-oxygen bonds, leading them to conclude that the sauropods' internal temperature was between 36 and $38^{\circ} \mathrm{C}$. Determine this temperatue range in ${ }^{\circ} \mathrm{F}$ and compare the body temperature to other modern animals. Which of the following animals do these dinosaurs most closely resemble?

Christy M.
Christy M.
Numerade Educator
01:47

Problem 84

According to the National Heart, Lung, and Blood Institute, LDL-cholesterol levels of less than $130 \mathrm{mg}$ of LDLcholesterol per deciliter of blood are desirable for heart health in humans. On the average, a human has $4.7 \mathrm{~L}$ of whole blood. What is the maximum number of grams of LDL-cholesterol that a human should have?

Will Li
Will Li
Numerade Educator
01:53

Problem 85

You have been sent to buy gold from prospectors in the West. You have no balance but you do have a flask full of mercury. You have been told that many prospectors will bring you fool's gold or iron pyrite in the hopes that you cannot tell the difference. Given the following densities for gold, mercury, and iron pyrite, how could you determine whether the samples brought to you are really gold?
$\begin{array}{ll}\text { gold } & 18.3 \mathrm{~g} / \mathrm{mL} \\ \text { mercury } & 13.6 \mathrm{~g} / \mathrm{mL} \\ \text { iron pyrite } & 5.00 \mathrm{~g} / \mathrm{mL}\end{array}$

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:05

Problem 86

Paleontologists will sometimes use the unit elephant (the mass of an African bull elephant) when describing the mass of large dinosaurs. One elephant ( $\mathrm{El})$ is defined as $6.00$ tons ( $\mathrm{El}=6.00$ tons). If a dinosaur is estimated to have a mass of $5.3$ elephants, what is its mass in pounds? (1 ton $=2000 \mathrm{lb})$

Jay Patel
Jay Patel
Numerade Educator
00:37

Problem 87

The height of a horse is measured in hands ( 1 hand $=$ exactly 4 in.). How many meters is a horse that measures $14.2$ hands?

David Collins
David Collins
Numerade Educator
00:54

Problem 88

Camels have been reported to drink as much as $22.5 \mathrm{gal}$ of water in $12 \mathrm{hr}$. How many liters can they drink in 30 . days?

Jay Patel
Jay Patel
Numerade Educator
06:22

Problem 89

You are given three cubes, $\mathrm{A}, \mathrm{B}$, and $\mathrm{C}$; one is magnesium, one is aluminum, and the third is silver. All three cubes have the same mass, but cube A has a volume of $25.9 \mathrm{~mL}$, cube B has a volume of $16.7 \mathrm{~mL}$, and cube $C$ has a volume of $4.29 \mathrm{~mL}$. Identify cubes $A, B$, and $C$.

Kim Trang Nguyen
Kim Trang Nguyen
Numerade Educator
03:04

Problem 90

When a chunk of wood burns, much more than just smoke is produced. In addition, nanotubes made of pure carbon are formed that have a structure resembling a roll of chicken wire. These nanotubes are stronger than steel, resistant to fire, and make good heat conductors. If a typical carbon nanotube has a diameter of $1.3 \mathrm{~nm}$, how many nanotubes would need to be laid side by side to construct a bridge $40.0$ feet wide?

AG
Ankit Gupta
Numerade Educator
00:52

Problem 91

The recommended daily allowance of magnesium for a college student is $380 \mathrm{mg}$. If $1 / 4$ cup of peanuts contains $67 \mathrm{mg}$ of magnesium, how many cups of peanuts should a college student eat to get his or her daily intake of magnesium?

Victor Salazar
Victor Salazar
Numerade Educator
01:01

Problem 92

In the United States, land is measured in acres. There are $43,560 \mathrm{ft}^{2}$ in each acre. How many $\mathrm{km}^{2}$ are in 125 acres?

David Collins
David Collins
Numerade Educator
02:13

Problem 93

A cube of aluminum has a mass of 500 . g. What will be the mass of a cube of gold of the same dimensions?

Ma Ednelyn Lim
Ma Ednelyn Lim
Numerade Educator
01:31

Problem 94

A $25.0-\mathrm{mL}$ sample of water at $90^{\circ} \mathrm{C}$ has a mass of $24.12 \mathrm{~g}$. Calculate the density of water at this temperature.

Jennifer Hudspeth
Jennifer Hudspeth
Numerade Educator
01:25

Problem 95

The mass of an empty container is $88.25 \mathrm{~g}$. The mass of the container when filled with a liquid $(d=1.25 \mathrm{~g} / \mathrm{mL})$ is $150.50 \mathrm{~g}$. What is the volume of the container?

Narayan Hari
Narayan Hari
Numerade Educator
01:53

Problem 96

Which liquid will occupy the greater volume, $50 \mathrm{~g}$ of water or $50 \mathrm{~g}$ of ethyl alcohol? Explain.

Khoobchandra Agrawal
Khoobchandra Agrawal
Numerade Educator
01:48

Problem 97

The Sacagawea gold-colored dollar coin has a mass of $8.1 \mathrm{~g}$ and contains $3.5 \%$ manganese. What is its mass in ounces $(1 \mathrm{lb}=16 \mathrm{oz})$, and how many ounces of Mn are in this coin?

David Collins
David Collins
Numerade Educator
00:44

Problem 98

The density of sulfuric acid is $1.84 \mathrm{~g} / \mathrm{mL}$. What volume of this acid will weigh 100 . g?

Himanshu Garg
Himanshu Garg
Numerade Educator
01:40

Problem 99

Dark-roasted coffee contains increased amonts of Nmethylpyridinium, or NMP, a ringed compound that is not present in green unroasted coffee beans. This compound seems to decrease the stomach acid production normally associated with drinking coffee. In coffee made from dark-roasted coffee, the concentration of NMP is $31.4 \mathrm{mg} / \mathrm{L}$. How many milligrams of NMP would you consume if you drank $2.00$ large cups of dark-roasted coffee? (One coffee cup contains $10.0$ fluid ounces of liquid.)

Ronald Prasad
Ronald Prasad
Numerade Educator
01:52

Problem 100

The density of palladium at $20^{\circ} \mathrm{C}$ is $12.0 \mathrm{~g} / \mathrm{mL}$, and at $1550^{\circ} \mathrm{C}$ the density is $11.0 \mathrm{~g} / \mathrm{mL}$. What is the change in volume (in $\mathrm{mL}$ ) of $1.00 \mathrm{~kg}$ Pd in going from $20^{\circ} \mathrm{C}$ to $1550^{\circ} \mathrm{C}$ ?

David Collins
David Collins
Numerade Educator
01:31

Problem 101

As a solid substance is heated, its volume increases, but its mass remains the same. Sketch a graph of density versus temperature showing the trend you expect. Briefly explain.

Kyle Gassaway
Kyle Gassaway
Numerade Educator
00:29

Problem 102

The first Apple computer had $5.0$ Mbytes of storage space on its hard drive, and the cost of this computer was $\$ 9995$. An Apple iPad Air 2 has 128 Gbytes of storage for a cost of S699. Calculate the cost per byte for each of these two Apple products. Which is a better buy?

Ali Soave
Ali Soave
Numerade Educator
01:10

Problem 103

A gold bullion dealer advertised a bar of pure gold for sale. The gold bar had a mass of $3300 \mathrm{~g}$ and measured $2.00 \mathrm{~cm} \times 15.0 \mathrm{~cm} \times 6.00 \mathrm{~cm}$. Was the bar pure gold? Show evidence for your answer.

James Kiss
James Kiss
Numerade Educator
01:43

Problem 104

A $35.0-\mathrm{mL}$ sample of ethyl alcohol (density $0.789 \mathrm{~g} / \mathrm{mL}$ ) is added to a graduated cylinder that has a mass of $49.28 \mathrm{~g}$. What will be the mass of the cylinder plus the alcohol?

Ronald Prasad
Ronald Prasad
Numerade Educator
View

Problem 105

Several years ago, pharmacists used the Apothecary System of Measurement. In this system, 1 scruple is equal to 20 grains (gr). There are $480 \mathrm{gr}$ in $1 \mathrm{oz}$, and in this system, there are $373 \mathrm{~g}$ in $12 \mathrm{oz}$. How many scruples would be in $695 \mathrm{~g}$ ?

Susan Hallstrom
Susan Hallstrom
Numerade Educator
01:08

Problem 106

You have just purchased a $500-\mathrm{mL}$ bottle of a decongestant medication. The doctor prescribed 2 teaspoons 4 times a day for 10 days. Have you purchased enough medication? $(1$ teaspoon $(\mathrm{tsp})=5 \mathrm{~mL})$

David Collins
David Collins
Numerade Educator
04:10

Problem 107

A sample of brine collected from the ocean has a density of $1.28 \mathrm{~g} / \mathrm{mL}$ and contains $7.55 \%$ sodium chloride.
(a) What is the volume in $\mathrm{L}$ of an $8.14-\mathrm{kg}$ sample of this brine?
(b) How many grams of brine are required to obtain $150.0$ grams of sodium chloride?

Arun Bana
Arun Bana
Numerade Educator
03:39

Problem 108

Your boss found a piece of metal in the lab and wants you to determine what the metal is. She is pretty sure that the metal is either lead, aluminum, or silver. The lab bench has a balance and a $100-\mathrm{mL}$ graduated cylinder with $50 \mathrm{~mL}$ of water in it. You decide to weigh the metal and find that it has a mass of $20.25 \mathrm{~g}$. After dropping the piece of metal into the graduated cylinder containing water, you observe that the volume increased to $57.5 \mathrm{~mL}$. Identify the metal.

Kim Trang Nguyen
Kim Trang Nguyen
Numerade Educator
05:11

Problem 109

Forgetful Freddie placed $25.0 \mathrm{~mL}$ of a liquid in a graduated cylinder with a mass of $89.450 \mathrm{~g}$ when empty. When Freddie placed a metal slug with a mass of $15.454$ g into the cylinder, the volume rose to $30.7 \mathrm{~mL}$. Freddie was asked to calculate the density of the liquid and of the metal slug from his data, but he forgot to obtain the mass of the liquid. He was told that if he found the mass of the cylinder containing the liquid and the slug, he would have enough data for the calculations. He did so and found its mass to be $125.934 \mathrm{~g}$. Calculate the density of the liquid and of the metal slug.

Pronoy Sinha
Pronoy Sinha
Numerade Educator
03:29

Problem 110

Jodi, a sculptor, has prepared a mold for casting a bronze figure. The figure has a volume of $225 \mathrm{~mL}$. If bronze has a density of $7.8 \mathrm{~g} / \mathrm{mL}$ and Jodi likes to use $90.0 \%$ of the bronze melted (she sometimes spills), how many ounces of bronze does Jodi need to melt in the preparation of the bronze figure?

Mercedes Mazza
Mercedes Mazza
Numerade Educator
07:00

Problem 111

Neutrinos are subatomic particles with a very low mass. Recent work at CERN, Europe's particle-physics lab near Geneva, Switzerland, suggests that neutrinos may have the ability to travel faster than the speed of light. If the speed of light is $1.86 \times 10^{8} \mathrm{mi} / \mathrm{hr}$, how many nanoseconds should it take for light to travel from CERN to the Gran Sasso National Lab in Italy, a $730.0 \mathrm{~km}$ journey? If a neutrino can travel the same distance 60 nsec faster, how many significant figures would you need to detect the difference in speed?

Nicholas Majtenyi
Nicholas Majtenyi
Numerade Educator
04:26

Problem 112

You decide to go sailing in the tropics with some friends. Once there, you listen to the marine forecast, which predicts in-shore wave heights of $1.5 \mathrm{~m}$, offshore wave heights of $4 \mathrm{~m}$, and temperature of $27^{\circ} \mathrm{C}$. Your friend the captain is unfamiliar with the metric system, and he needs to know whether it is safe for your small boat and if it will be warm. He asks you to convert the measurements to feet and degrees Fahrenheit, respectively.

Dading Chen
Dading Chen
Numerade Educator