Miss Spiteri Honors Chemistry
Name __________________________________________________ Date _________________________ Period _____
Purpose: To determine the density of various liquids and solids and use the calculations to understand relative buoyancies.
Background Principles: Using the word bank provided, fill in the blanks in the paragraph below and write the complete paragraph in the background knowledge section of your lab book.
Density is a _______________ _________________. ________________ measures the amount of matter concentrated in a given amount of space, and can be calculated by taking the __________ of a substance divided by its _________________. Therefore, the equation for calculating density is ________________. The metric unit used to measure mass is the _______________. The common metric unit used to measure liquid volume in the chemistry laboratory is the ___________________.
Therefore, for liquids, the density unit will be ________________________________. The density of pure water is exactly __________. If a solid is measured, only the volume unit will change. The density of solids is expressed in _____________________________.
To determine the mass of an object in the lab, use an ___________________. To determine the volume of a regularly shaped object, use a ______________________. We can also determine the volume of irregularly shaped objects using the concept of ____________ _________________. To find the volume of the irregularly shaped objects in the lab, we must put the object and water in a
__________________ ____________. graduated cylinder physical property
Density milliliter (mL) g/cm 3
WORD BANK grams per milliliter (g/mL) electronic balance volume mass water displacement
1 g/mL gram (g) metric ruler
D = m/v
Materials
 20mL graduated cylinder
 100mL graduated cylinder
 Water (DI and Tap)



Electronic balance metric ruler
Pb sinkers
Safety: List the safety precautions you will take during this lab
 Density cubes
 Isopropyl alcohol
 cooking oil

Miss Spiteri Honors Chemistry
Protocol
Part A: The Density of Common Liquids
1. Use the balance to find the mass of the graduated cylinder. Record this value in data table A-1.
2. Use the clean graduated cylinder to measure 15 mL of de-ionized (DI) water.
3. Find the mass of the cylinder and water. Record this value in data table A-1.
4. Subtract to find the mass of the water alone. Record in data table A-1.
5. Calculate the density of water and record this in data table A-1.
6. Repeat steps 2-5 with isopropyl alcohol and cooking oil (instead of water).
7. Clean the graduated cylinder carefully and thoroughly.
Part B: The Density of Solids
1. Use the electronic balance to measure the mass of the Pb sinker. Record this value in data table B-1.
2. Fill the graduated cylinder with 40 mL of tap H
2
O.
3. Use water displacement to find the volume of the Pb sinker. Carefully place the sinker into the cylinder with water. The water will rise to a new level. The difference between the original level and the new level is equal to the volume of the sinker. (Yes, subtract!) Record this volume in data table
B-1.
4. Using the electronic balance and metric ruler, determine the mass and volume of each of the density cubes. Record these values in data table B-2.
5. Using your measurements, calculate the density of each of the cube materials and record the densities in data table B-2.
6. Determine your percent error in calculating the density of water, lead, copper, and aluminum. The theoretical density for each substance is provided in data table B-3. Record your experimental densities (from data table B-2) and calculate the percent error for each substance. Record your data in table B-3. (HINT: see your notes for the formula to calculate percent error)
Observations: What do you notice about the colors of the various metals? What did you observe during water displacement?
Data: DON’T FORGET TO INCLUDE UNITS!
Data Table A-1: The Density of Common Liquids
Object(s)
Mass of cylinder + liquid
Mass of cylinder alone
Mass of liquid
Volume of liquid
Density of liquid
DI water (dH
2
O)
Isopropyl Alcohol – 70%
(C
3
H
7
OH)
Cooking Oil – Oleic Acid
(C
18
H
34
O
2
)

Miss Spiteri
Data Table B-1: The Density of Lead (Pb)
Mass of Pb sinker
Volume of Pb sinker
Density of Pb
Honors Chemistry
Data Table B-2: The Densities of Various Substances as Cubes
Object
Brass Cube
Copper (Cu) Cube
Steel Cube
Aluminum (Al) Cube
Wood (pine) Cube
Mass Volume Density
Data Table B-3: Percent Error
Pure Substance dH
2 o
Theoretical Density Experimental Density
1.00 g/mL
Percent Error
Lead (Pb)
Copper (Cu)
Aluminum (Al)
11.35 g/cm 3
8.96 g/cm 3
2.70 g/cm 3
Data Processing: Be certain to include each of the following components in this section of your lab report.
 Density calculations for DI water, isopropyl alcohol, and cooking oil
 Volume calculations for each cube: brass, copper, steel, aluminum, and wood
 Density calculation for each solid: lead, brass, copper, steel, aluminum, and wood
 Percent error calculation for dH
2
O, lead, copper, and aluminum
Discussion Questions: Answer the following in complete sentences
1. Which liquid has the greatest density? Which solid has the greatest density?
2. If you carefully poured oil and water together in a 50 mL beaker, which liquid would float on top?
DRAW the beaker and label the layers you would observe.
3. if you carefully poured isopropyl alcohol and water together in a 50 mL beaker, which liquid would float on top? DRAW the beaker and label the layers you would observe.
4. Write a “rule” for the observations of the beaker contents in questions 2 & 3. (Hint: where do you find the most dense material? Where do you find the least dense material?)
5. Ice cubes float in liquid water. Which is more dense, ice or liquid water? Does this seem reasonable to you? Explain.
6. What is meant when an object is said to be buoyant?
7. Make a prediction about the relative buoyancies of the following objects: oil, pure water, alcohol, lead, pine. If these materials were carefully put into the same container, list the layers that would form in order from bottom to top.
Conclusion and Evaluation: For this section, refer to the Lab Format guidelines.