# Units and Calculations Homework Problem Set

This problem set was developed by S.E. Van Bramer for Chemistry 145 at Widener University.

1. Give the name and abbreviation of the SI Unit for:
1. Length
2. Mass
3. Time
4. Electric Current
5. Temperature

2. Give the abbreviation for the following units and describe what they are used to measure:
1. meter
2. liter
3. cubic centimeter
4. milliliter
5. degree Celcius
6. kelvin

3. Give the name and the abbreviation (without looking in the book) of the SI or metric prefix for:
1. 10-12
2. 106
3. 10-9
4. 10-2
5. 10-3
6. 109
7. 103
8. 10-6

4. Express the following numbers in scientific notation with the appropriate number of significant figures:
1. 10980000000
2. 414100
3. 0.000095162
4. 746.5x107

5. Perform the following calculations and give the answer in scientific notation with the correct number of significant figures.
1. 30.84 + 9.74
2. 30.84 + 9.74486
3. 30.845 + 9.74
4. 30.845 + 9.75
5. 145 + 1.54x10-6
6. 40.79 - 1.18432
7. 1.43 x 0.848
8. 1.43 x 0.84828
9. 136 x 3.0
10. (7.601x107) x (8.09x10-4)
11. 70.22
12. 947731/2

6. Preform the following mathematical operations and give the answer with the correct number of significant figures:

1. 2. 3. 4. 7. Perform the following unit conversions. Express your answers in scientific notation with the appropriate number of significant figures.

1. Convert 78.01 inches into: feet, meters, centimeters, millimeters and kilometers.
2. Convert 14511 feet into miles, kilometers and meters.
3. Convert 15.42 meters into kilometers, centimeters, millimeters, micrometers, and nanometers.
4. Convert 98.6 °F into °C and K.
5. Convert 75 miles per hour into: km per hour and m s-1.
6. Convert 23.15 m2 into ft2, in2, and cm2
7. Convert 500.0 cm3 into in3, m3, L, and mL.

8. In the movie Goldfinger, James Bond foils a plot to break into Fort Knox. 007 does some quick mental calculations to determine the feasibility of removing the gold. If the price of gold is \$14.00 per troy ounce (31.1035 grams) at the time the movie was produced, what is the mass (in kg) of 1 million dollars of gold? What is the volume of 1 million dollars of gold in L. How much would this gold be worth today if the price of gold is \$9068.77 per kg?

9. The following experiment is performed with an unknown liquid. The liquid is added to a graduated cylinder with a mass of 54.6789 grams. After 20.00 mL of the liquid is added to the cylinder (at 298 K), the mass is 74.6215 grams. Is the liquid water? How do you know? If it is not water, what could it be?

The experiment is repeated with a second liquid, after 21.3 mL of this liquid (at 20 °C) is added the mass of the cylinder is 72.7364 grams. Is the second liquid ethanol? How do you know? If it is not ethanol, what could it be?