Deck 1: Introduction to Chemistry

Question 1

The Study of Chemistry
Identify the physical and chemical properties noted in the following statement: When a piece of iron is exposed to air it corrodes, forming a layer of red-brown powder that flakes off and is denser than the original material.

Answer 1

Physical properties include the flaking of the powder and density comparison. The chemical properties here is the reaction to form the iron oxide(s).

Question 2

Observations and Models
Two golfers are practicing shots around a putting green. Each golfer takes 20 shots. Golfer 1 has 7 shots within 1 meter of the hole, and the other 13 shots are scattered around the green. Golfer 2 has 17 shots go into a small sand trap near the green and three just on the green near the trap. Which golfer is more precise? Which is more accurate?

Answer 2

Golfer 2 is more precise because his efforts are grouped more tightly about a central point (mean) even if it's not the intended spot. Golfer 1 is more accurate as there are more shots very close to the accepted "value" (the hole).

Question 3

The Study of Chemistry
How can a liquid be distinguished from a fine powder? What type of experiment or observation might be undertaken?

Answer 3

Experiments related to the physical properties of the liquid and fine powder would prove useful. These could include properties such as surface tension, flow, and behavior in a high static electricity environment.

Question 4

Insight into Aluminum
Use the web to determine the amount of aluminum used in the US in a single year. What is the primary use for this material?

Question 5

Numbers and Measurements
Oxygen boils at − 186 ° C. What is this temperature in Kelvin?

Question 6

The Study of Chemistry
All molecules attract each other to some extent, and the attraction decreases as the distance between particles increases. Based on this idea, which state of matter would you expect has the strongest interactions between particles, solids, liquids or gases?

Question 7

Numbers and Measurements
The largest computers now include disk storage space measured in terabytes. How many bytes are in a terabyte? (Recall that in computer terminology, the prefix is only "close" to the value it designates in the metric system.)

Question 8

Observations and Models
What is a law of nature? Are all scientific laws examples of a law of nature?

Question 9

Insight into Aluminum
What properties of aluminum might cause you concern if you had to use the aluminum tableware that Napoleon employed to impress his guests?

Question 10

Numbers and Measurements
What is the difference between a qualitative and a quantitative measurement?

Question 11

Insight into Aluminum
Use the web to determine the difference in how much aluminum is recycled in states where there are deposits on aluminum cans versus states where recycling is voluntary? What is the most reliable way to estimate this value? What uncertainty is there in the estimate?

Question 12

Numbers and Measurements
Use the web to determine how the btu unit was initially established. For the engineering applications where this unit is still used today, why is it a sensible unit?

Question 13

The Study of Chemistry
Why do physical properties play a role in chemistry if they do not involve any chemical changes?

Question 14

Numbers and Measurements
What is a "derived" unit?

Question 15

The Study of Chemistry
Which of the following items are matter and which are not?
a) a flashlight
b) sunlight
c) an echo
d) air at sea level
e) air at the top of Mount Everest

Question 16

Observations and Models
What is the difference between a hypothesis and a question?

Question 17

Observations and Models
Suppose you are waiting at a corner for a bus. Three different routes pass this particular corner. You see a bus pass by from the two routes you are not interested in taking. When you say to yourself, "My bus must be next," what type of reasoning (deductive or inductive) are you using? Explain your answer.

Question 18

Numbers and Measurements
Convert the value 38.4 ppm into ppb.

Question 19

Observations and Models
Complete the following statement: Data that have a small random error may be (accurate, precise, both, or neither).

Question 20

The Study of Chemistry
Do the terms element and atom mean the same thing? If not how do they differ?

Question 21

Problem Solving in Chemistry and Engineering
A metallic cylinder displaces 91.0 mL and has a mass of 245.7 g. What is the density of the metal?

Question 22

Numbers and Measurements
A rock is placed on a balance and its mass is determined to be 22.410 g. When the rock is then placed in a graduated cylinder that originally contains 11.34 mL of water the new volume is 17.82 mL. What should the density of the rock be reported as?

Question 23

Focus on Problem Solving Exercises
A student was given two metal cubes that looked similar. One was 1.05 cm on an edge and had a mass of 14.32 grams; the other was 2.66 cm on a side and had a mass of 215.3 grams. How can the student determine if these two cubes of metal are the same material using only the data given?

Question 24

Problem Solving in Chemistry and Engineering
Mercury has a density of 13.6 g/mL. What is the mass of 4.72 L of mercury?

Question 25

Problem Solving in Chemistry and Engineering
In the description of the refining of aluminum the molecular scale depiction of precipitation was not included. Use the web to determine what chemicals are involved in the precipitation process and draw a molecular scale drawing of this reaction.

Question 26

Insight into Materials Selection and Bicycle Frames
Use the web to research the elastic modulus and yield strength of carbon fiber composites. How do these materials compare to aluminum, steel and titanium?

Question 27

Problem Solving in Chemistry and Engineering
Carry out the following unit conversions.
a) 82 μ g to mg
b) 6.73 × 10 ^{− 4} mm to nm
c) 1.37 × 10⁶ nA to Ma
d) 4.8 × 10¹⁸ mW to GW

Question 28

Problem Solving in Chemistry and Engineering
If the cost to fill a gasoline tank is $78.42 and gasoline costs $3.66/gal, how many gallons does the tank hold? How many L of gasoline could be purchased for $50.00?

Question 29

Insight into Materials Selection and Bicycle Frames
Rank aluminum, steel and titanium in order of increasing stiffness.

Question 30

Numbers and Measurements
In an attempt to determine the velocity of a person on a bicycle, an observer uses a stopwatch and times the length of time it takes to cover 25 "squares" on a sidewalk. A measurement of one of the squares shows it to be 1.13 m long. The bicycle takes 4.82 seconds to travel this far. What velocity, in m/sec, should the observer report?

Question 31

Problem Solving in Chemistry and Engineering
Draw a molecular scale picture to show how a crystal differs from a liquid.

Question 32

Focus on Problem Solving Exercises
A solution of ethanol in water has a volume of 54.2 mL and a mass of 49.6 g. What information would you need to look up and how would you determine the percentage of ethanol in this solution?

Question 33

Insight into Materials Selection and Bicycle Frames
Aluminum is not as strong as steel. What other factor should be considered when comparing the desirability of aluminum versus steel if strength is an important consideration for a design?

Question 34

Problem Solving in Chemistry and Engineering
If a particle is traveling at 98% of the speed of light in a vacuum (2.998 x 10⁸ m/s), what is its velocity in miles per hour? 1.00 miles = 1.61 km.

Question 35

Numbers and Measurements
Express each of the following temperatures in ° C.
a) 177 K
b) 298 K
c) 4 K
d) 1500 K

Question 36

Problem Solving in Chemistry and Engineering
The distance between two atoms in a molecule is 148 pm. What is this distance in meters?

Question 37

Numbers and Measurements
Measurements indicate that 23.6% of the residents of a city with a population of 531,314 are college graduates. Considering significant figures, how many college graduates are estimated to reside in this city.

Question 38

Numbers and Measurements
Assuming the numbers given are measurements, carry out the indicated arithmetic operations and give the answer with the correct number of significant figures.
a) 7.132 / 6
b) 3.65 × 10² + 8.1 × 10³
c) 18.13 − 1.3
d) 9 × 10 ^{− 6} × 1.33 × 10 ^{− 3}

Question 39

Focus on Problem Solving Exercises
Battery acid has a density of 1.285 g/mL and contains 38.0% sulfuric acid by mass. Describe how you would determine the mass of pure sulfuric acid in a car battery, noting what item(s) you would have to measure or look up.

Question 40

Numbers and Measurements
How many significant figures are present in each of the following experimental measurements?
a) 0.003 m
b) 6030 kg
c) 400.3 s
d) 0.000701 L
e) 31.624 km

Question 41

Focus on Problem Solving Exercises
If corn is traded by the "bushel" and an acre of crop land yields an average of 240 bushels of corn per acre, how would you determine the volume of corn in L is produced by a 160 acre field? What would you have to look up to solve the problem?

Question 42

Focus on Problem Solving Exercises
Imagine you place a cork measuring 1.30 cm × 4.50 cm × 3.00 cm in a pan of water. On top of this cork you place a small cube of lead measuring 1.15 cm on a side. Describe how you would determine if the combination of the cork and lead cube will still float in the water. Note any information you would need to look up to answer the question.