Title: Density Lab
Density is an important intensive physical property of matter. By itself or in conjunction with other
properties density can be used to identify substances. Density is defined as the quantity of matter in a given
unit of volume. This relationship expressed mathematically is;
Density is Mass/ Volume
Purpose: The purpose of this lab is to determine the density of a metal object and two (2) liquids. The
correct use of significant digits and proper laboratory report set up are secondary purposes.
Materials
Procedure:
Part A : The Density of a Metal Cylinder
1.
Measure the mass of a metal cylinder on an analytical balance. Be careful not to touch the metal
directly with your hands prior to deterring the mass. Record the mass as given on the balance in
the data table.
2.
Measure the length and diameter of the metal cylinder with a centimeter ruler. Your measurements
should have TWO decimal places. Record the measurements in the data table.
3.
Put exactly 10.0 mL of water in a 50.0 mL graduated cylinder. Carefully place the metal cylinder
in the graduated cylinder. Record the initial and final water levels to one decimal place in the data
table.
Part B: The Density of Liquids
1.
Determine the mass of an empty dry 50.0 mL graduated cylinder. Record the mass in your data
table.
2.
Place exactly 10.0 mL of water in the empty 50.0 mL graduated cylinder. Record this mass in the
data table.
3.
Dry the graduated cylinder and place exactly 10.0 ml of ethanol in the empty 25.0 mL graduated
cylinder. Determine the mass of the graduated cylinder and ethanol and record this in the data
table.
Data
Part A
Mass of metal cylinder
Length of cylinder
Diameter of metal cylinder
Initial volume of water
Final volume of water
Part B
Mass of empty graduated cylinder
Mass of cylinder + 10.0 mL of water
Mass of cylinder and 10.0 mL of ethanol
Calculations:
Show all work and include units and sig digits.
1. Calculate the volume of the metal cylinder from its dimensions using the formula
V = r2L
2. Calculate the density of the metal cylinder using the volume obtained in the previous question.
3.Clacuate the volume of the metal cylinder from its water displacement.
4.Calculate the density of the metal cylinder using the volume in the previous question.
5. Calculate the mass of 10.0 mL of water.
6. Calculate the density of water.
7. Calculate the mass of 10.0 mL of ethanol.
8. Calculate the density of ethanol.
9. Obtain the true value for the densities from your instructor.
a) Calculate the % error for the density of the metal with each method. What was your
sample of metal?
b) Calculate the % error for the density of water.
c) Calculate the % error for the density of ethanol.
Questions:
1. Which method for the determination of density of the metal was most accurate? Why?
2. Specific gravity is defined as the mass of a substance divided by the mass of an equal volume of water
(or the density of the substance divided by the density of water). Determine the specific gravity of ethanol.
3. How would your results be affected if a 25.0 mL graduated cylinder was used and exactly 15.0 mL of
your liquid was used? Be specific.
4.How would your value for the density be affected if some water remained in the graduated cylinder when
you added the ethanol? Be specific.
5.Define meniscus, precision, accuracy, graduated cylinder, balance and significant figures.
Conclusion: