CHEM 1115 Unit 1 Practice Problems

Please note that the following problems do not represent everything that will be on the exam. Use your objectives to study!!!

1. How many significant figures are in the following measurements?

a. 1.09 g

b. 0.00312 km

c. 9.120 x 10^-3 L

d. 10,000 mi

2. Perform the following calculations and report your answer using the rules for calculations involving measured values (i.e. with the correct number of significant figures).

a. 8.074 + 9.11 – 2.5 =

b. (1.04 x 10⁵)(6.3 x 10³)/(2.908 x 10^-6) =

c. 9.113 – 8.993 =

8.993

3. A 12.5 mL sample of liquid has a mass of 10.897 g. What is the density of the liquid?

4. What is the mass of a 5.0 cm³ piece of metal if its density is 8.91 g/cm³?

5. What volume of a liquid with a density of 0.890 g/mL is needed to provide 25.000 g?

6. A silver colored solid cube has the following dimensions: 0.50 cm x 0.50 cm x 1.00 cm.

a. If it has a mass of 0.625 g, calculate its density.

b. If the density of aluminum is 2.702 g/cm³, is this sample pure aluminum?

7. Using the equations given in your book and class, convert 298 K to ^oF.

8. A particular brand of sunscreen contains 12.0% PABA (p-aminobenzoic acid) by mass. How many kilograms of PABA are needed to produce exactly 500 tubes of sunscreen if each tube contains 8.0 ounces of sunscreen? Use dimensional analysis and any conversion factors needed from your text.

9. Using only the metric to metric conversion factors you were required to learn and the ones given below, perform the following conversions using dimensional analysis.

2.20 lb = 1 kg 4 qt = 1 gal 1 cal = 4.184 J

2.54 cm = 1 in 1 L = 1.0567 qt 1 eV = 1.602 x 10^-19 J

12 in = 1 ft 1 furlong = 660.0 ft 1 mi = 5280 ft

1 min = 60 s 1 hr = 60 min 1 day = 24 hr

1 fortnight = 14 days

1. 1.00 g/cm³ = ________ lb/gal

b. 2.5 x 10⁴ mg = _______ lb

c. 1.8 x 10⁶ cm³ = ________ ft³

d. 5.0 x 10²⁴ eV = ________ kcal

e. 11.2 m/s = __________furlong/fortnight