Question 1

Numbers and Measurements 
What is a "derived" unit?

Accepted Answer

A derived unit is a unit that is made up of two or more base units.

Question 2

Focus on Problem Solving Exercises 
A student was given two metal cubes that looked similar. One had an edge of 1.05 cm and had a mass of 14.32 grams, and the other had an edge of 2.66 cm 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?

Accepted Answer

Determine the density of each cube. If the densities vary significantly, the cubes are not of the same material. If the densities are similar, the student can suggest that the materials "appear" to be similar but still can be unsure about the result. In this particular case, the first cube has a density of 12.4 g\cm ³and the second has a density of 11.4 g\cm ³. This difference suggests that the two materials are not the same.

Question 3

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?

Accepted Answer

To determine the % of ethanol one would have to know the density of ethyl alcohol. Make the assumption that the primary components are water and ethanol. Set "x" equal to the percentage of ethanol in the sample, and "1-x" is the percentage of water. Multiply "x" by the density of ethanol and to this quantity add "1-x" multiplied by the density of water. The sum of these two components should equal the overall density found by mass\volume.

Question 4

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?

Accepted Answer

The answer of Numbers and Measurements 
Measurements indicate that 23.6%...

Question 5

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

Accepted Answer

The answer of Observations and Models 
What is a law...

Question 6

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

Accepted Answer

The answer of Problem Solving in Chemistry and Engineering 
Draw...

Question 7

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?

Accepted Answer

The answer of Insight into Aluminum 
Use the web to...

Question 8

What are the two important features that make indium tin oxide a reliable material for touchscreen devices?

Accepted Answer

The answer of What are the two important features that...

Question 9

Problem Solving in Chemistry and Engineering If a particle is traveling at 98% of the speed of light in a vacuum (2.998 x 10 ⁸m\s), what is its velocity in miles per hour? 1.00 mile = 1.61 kilometers.

Accepted Answer

The answer of Problem Solving in Chemistry and Engineering 
If...

Question 10

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

Accepted Answer

The answer of Numbers and Measurements 
Oxygen boils at −...

Question 11

Problem Solving in Chemistry and Engineering 
An engineer designed a process to manufacture ball bearings. The mass of each bearing was measured to be within 0.15% of 100 grains. What range of bearing masses, in mg, will meet this tolerance? 1 grain = 64.79891 mg.

Accepted Answer

The answer of Problem Solving in Chemistry and Engineering 
An...

Question 12

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?

Accepted Answer

The answer of Numbers and Measurements 
In an attempt to...

Question 13

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, how would you determine that the volume of corn in L is produced by a 160 acre field? What would you have to look up to solve the problem?

Accepted Answer

The answer of Focus on Problem Solving Exercises 
If corn...

Question 14

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?

Accepted Answer

The answer of Insight into Materials Selection and Bicycle Frames...

Question 15

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

Accepted Answer

The answer of Focus on Problem Solving Exercises 
Imagine you...

Question 16

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?

Accepted Answer

The answer of The Study of Chemistry 
All molecules attract...

Question 17

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?

Accepted Answer

The answer of Numbers and Measurements 
Use the web to...

Question 18

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

Accepted Answer

The answer of The Study of Chemistry 
Do the terms...

Question 19

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?

Accepted Answer

The answer of Problem Solving in Chemistry and Engineering 
Mercury...

Question 20

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 in which recycling is voluntary. What is the most reliable way to estimate this value? What uncertainty is there in this estimate?

Accepted Answer

The answer of Insight into Aluminum 
Use the web to...

Exam 1: Introduction to Chemistry

Numbers and Measurements What is a "derived" unit?

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?

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?

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

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

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?

What are the two important features that make indium tin oxide a reliable material for touchscreen devices?

Problem Solving in Chemistry and Engineering If a particle is traveling at 98% of the speed of light in a vacuum (2.998 x 10 8 m\s), what is its velocity in miles per hour? 1.00 mile = 1.61 kilometers.

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

Problem Solving in Chemistry and Engineering An engineer designed a process to manufacture ball bearings. The mass of each bearing was measured to be within 0.15% of 100 grains. What range of bearing masses, in mg, will meet this tolerance? 1 grain = 64.79891 mg.

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, how would you determine that the volume of corn in L is produced by a 160 acre field? What would you have to look up to solve the problem?

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?

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?

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?

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

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?

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 in which recycling is voluntary. What is the most reliable way to estimate this value? What uncertainty is there in this estimate?

Problem Solving in Chemistry and Engineering If a particle is traveling at 98% of the speed of light in a vacuum (2.998 x 10 ⁸m\s), what is its velocity in miles per hour? 1.00 mile = 1.61 kilometers.