Experiment A: Density
Community College of Philadelphia
Department of Chemistry

CHEM 101 Distance Course

Laboratory Report Sheet
Name:

Date:

Email:

Laboratory Instructor:

Course Nbr.: CHEM 101 Distance

Section:

Experiment Nbr.: A – Home-based Lab

Experiment Title: Virtual Density Lab – Version 2

Purpose:

Concepts related to the textbook:

Conclusion:

Chem 101 Distance – Experiment A: Virtual Density Lab (Version 2)

Background

Density is a physical property that relates the mass and volume of a particular substance. It has units of mass/volume, typically g/mL or g/cm3.

The density of a substance does not depend on the amount of the substance present. Because it is specific to that substance, density can be used to identify a material. Substances that have higher densities contain particles that are closely packed together, while lower densities contained particles that are father apart.

Densities of objects can be determined by finding the mass and the volume of the object, then using Equation 1 for the final calculation. Mass is usually determined using a balance. Volume, however, can be determined in two ways: by direct measurement and by displacement.

The volume of an object can be determined by direct measurement if the object has a regular shape. Using a centimeter ruler, for example, lengths, widths, heights, or diameters can be estimated. Volume is then determined by knowing the correct formula for volume. The following are volume formulas to use when direct measurements are possible.

Volume of a Cube Length3

Volume of a Box

Volume of a Cylinder

Volume of a Sphere

(Note: r = Radius = ½ x Diameter)

Second, if an object is irregularly shaped, volume can be determined by displacement using a graduated cylinder. First a graduated cylinder is filled to a volume that will at least cover the object(s) that will be added to the cylinder. An initial reading of that volume is recorded. Then the object is added, and a final volume reading is recorded. The difference between the final and initial volumes is the displaced volume (i.e. the volume of the added object).

Part 1: Videos

Watch the following videos to gain some back information on density, and to see a density experiment similar to one we would have completed in the lab.

Video 1 – Density Background: https://www.youtube.com/watch?v=if2aH9OKZLU

Video 2 – Volume by Displacement Experiment: https://www.youtube.com/watch?v=kBF1PTgRjbQ&t=4s

Part 2: Density and Volume Displacement Virtual Experiment

1. Go to the following website: https://whyy.pbslearningmedia.org/resource/arct15-sci-densitylab/density-lab/

2. Click on the blue “Launch” button in the middle of the main image. This will take you to a virtual laboratory page where we can conduct a few density experiments!

3. Select the blue button at the top of the page that reads “Turn Fluid into Water.” This will make sure that the fluid in the beaker is water. This is important for the volume displacement part of the experiment.

4. Next, select the “Gold” button in the bottom right portion of the screen. This will turn the object in question into gold.

5. To find the mass of the gold object, drag it onto the balance at the right side of the screen. Record the given mass in Table 1.

6. To find the object’s volume, record the initial volume of water in the beaker in Table 1. Make sure there are no objects in the beaker for this initial volume. Next, place the gold object above the beaker and drop it into the water. The object will displace some of the water, and you will observe an increase in the total volume. Record this final volume in Table 1. The difference between the initial volume and the final volume will determine the volume of the object (Equation 2). Record the object volume in Table 1 as well. (Note – Show a sample calculation in the space provided)

7. Use the object volume, the mass measurement, and Equation 1 to determine the density of the object. Record your results in Table 1. (Note – Show a sample calculation in the space provided)

8. Repeat steps 4 – 7 using the “Iron” button, the “Lead” button, and the unknown object (? ? ? ? ?) button. Record your results in Table 1.

9. Once you have calculated the density of each object, rank the densities from most dense (1) to least dense (4) in the last column of Table 1.

Table 1: Density using Volume by Displacement

Object

Mass (g)

Initial Volume (mL)

Final

Volume (mL)

Object Volume (mL)

Density (g/mL)

Density Rank

Gold

Iron

Lead

Unknown

Sample Calculations for Volume and Density in Table 1:

Part 3: Questions

1. Take a look at Equation 1 on the first page. Does this equation suggest a directly proportional or indirectly proportional relationship between mass and volume with regards to density? If the mass of an object were to increase, what should happen to the volume?

2. What was the density of the Unknown Object in Part 2? Using the following density list, determine the object’s identity: Aluminum = 2.70 g/mL, Diamond = 3.26 g/mL, and Copper = 8.90 g/mL.

3. What is the density of an object with a volume of 8.29 mL and a mass of 16.31 g? (show your work)

4. Give the steps needed to determine the volume of an object by displacement.

5. Object A is less dense than Object B. If both objects are the same mass, what can be said about the volume of A as compared to the volume of B? Explain your reasoning.

6. A spherical-shaped object has the following dimensions: Diameter = 2.9 cm and Mass = 7.875 g. Calculated the density in g/cm3. (show your work)

Worksheet developed by M. O’Connor (02/16/2021) using the following resources…

1. https://whyy.pbslearningmedia.org/resource/arct15-sci-densitylab/density-lab/

2. Chemistry 110 Lab Manual published by Thomson College Publishing, 2011

3. Timberlakes’, Basic Chemistry, Pearson, 5th ed., 2017