Practice Problems Dealing With Density

Strategy:

1. First recognize what kind of problem it is (that it is a density problem).
2. Write down the equation for density:
3. Ask yourself what is given: D? M? V? There must be enough information so there is only one unknown!
4. Solve for the unknown. (Identify whether it is D, M or V.)
5. Substitute in the number including the units. If the units don’t cancel out, you know you need to do some unit conversion.
6. After you get your answer, reread the question to be sure you have answered the question and not end up with something else!

(Note: This is only an exercise to density problems. If you don’t understand how to do unit conversions you need to get help elsewhere, such as from the tutorial accessed from my Homepage. It is also assumed that you already know how to handle sig. fig. in these calculations.)

Given: 1 inch = 2.54 cm exactly

1 lb = 454 g

1 qt = 0.946 L

Answers are at the bottom. Take time to write out your setups and check your significant figures before you look at the answers.

1. A piece of gold ingot weighs 528.4 g. What is its volume if the density of gold is 19.3 g/cm³.

2. Water is placed into a graduated cylinder and the total mass was determined to be 58.34 g. The level of the water was at the 48.8 mL mark. An unknown metal slug was then immersed into the graduated cylinder of water and the level rose to the 84.0 mL mark. The mass of the graduated cylinder, water and metal slug was determined to be 373.46 g. What is the density of the metal slug in g/cm³?

3. Chloroform was once used as an anesthetic. It has a density of 1.483 g/mL at 20°C. If we fill up a 2.0 quart-bottle with chloroform, what is the mass of the chloroform in grams?

4. A block of special glass has a density of 2.21 g/cm³ it weighs 0.967 ounces. It is 1.28 cm thick and 1.10 inch wide. What is its height in centimeters?

Answers to Practice Problems on Density

1. 27.4 cm³

2. 8.95 g/cm³ (Remember that 1 cm³ = 1 mL)

3. 2.8x10³ g

4. 3.47 cm