Density Lab



Density Lab Name:__________________

Density is defined as the mass per unit volume where the mass can be measured with the balance and the volume can be measured in a variety of ways. Density is an intensive physical property and it is a derived unit because its formula is mass / volume.

Purpose: The purpose of this experiment is to practice making some quantitative measurements in the laboratory with different instruments which give different levels of accuracy, to become familiar with derived units such as density, to compare densities of different substances, and to practice using significant digits in calculations.

Materials: 10 mL graduated cylinder liquid A liquid B

100 mL beaker ruler balance

mystery substance

Procedure:

1. Clean and dry your cylinder if dirty. Mass each piece of glassware.

2. Pour about 5 mL (record exact volume) of liquid A into your graduated cylinder (pour slowly) and obtain the mass. Use the one of the graduated cylinders next to liquid B and pour about 50 mL (record exact volume) of liquid B into your beaker and obtain the mass.

3. Mass your mystery substance and make necessary measurements in order to determine it volume.

4. Put your mystery substance into your beaker with liquid B and record your observations.

5. All liquids can go down the sink; wash your glassware when you are done.

Data: (don’t forget units and proper sig digs)

Mass of 10 mL graduated cylinder __________

Exact volume of liquid A in the cylinder __________

Mass of cylinder and liquid A __________

Mass of liquid A __________

Mass of 100 mL beaker __________

Exact volume of liquid B in the beaker __________

Mass of beaker and liquid B __________

Mass of liquid B __________

Mass of mystery substance __________

Measurements of mystery substance:

Observations of mystery substance in liquid B:

Calculations: Show work for partial credit. Box your final answer. Don’t forget units and proper sig digs on your answer.

1. What is the density of liquid A?

2. What is the density of liquid B?

3. What is the volume of the mystery substance?

4. What is the density of the mystery substance?

Analysis: The identity of liquid B is water with an actual density of 1.00 g/mL. What is your percent error with 3 sig digs for the density of liquid B?

Density Lab Conclusion Questions:

The factor label method works well on density problems because the density is a conversion factor which can be used to convert mass to volume or volume to mass. Get in the habit of rewriting densities:

0.86 g/mL = 0.86 g

1 mL

Sample problem: What is the volume in liters (L) of an object with a mass of 3.29 g and a density of 2.9 g/mL?

3.29 g x 1 mL x 1 x 10-3 L = 0.011 L (2 sig digs)

2.9 g 1 mL

Use complete sentence where applicable. Show work with sig digs and unit for mathematical problems.

1. Would the mystery substance float in liquid A? Why or why not?

2. What would happen if you poured liquid A into liquid B?

3. What is the mass in grams of 35.00 mL of a liquid with a density of 0.980 g/mL?

4. What is the volume in cubic centimeters of 129.0 kg of a solid with a density of

20 g/cm3?

5. What is the mass in kilograms of 2050 mL of water?

6. What is the volume in microliters of 950 mg of a solid with a density of 1.860 g/cm3?

(1 mL = 1 cm3)

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