AP Chemistry
Name: ___________________________
Group Members:
___________________________
___________________________
___________________________
A Measurement Challenge
Purpose and Objectives
Density is a physical property of matter, as each element and compound has a unique density
associated with it. Density defined in a qualitative manner as the measure of the relative "heaviness"
of objects with a constant volume.
For example: A rock is obviously more dense than a crumpled piece of paper of the same size.
A styrofoam cup is less dense than a ceramic cup.
Density may also refer to how closely "packed" or "crowded" the material appears to be - again refer
to the styrofoam vs. ceramic cup.
Your purpose for this laboratory experiment is to predict the mass of a rectangular block based on
length measurements and known density values.
Safety and Disposal
None
Equipment
Metric ruler
unknown samples (blocks)
laboratory balance
Procedure
1. Obtain a block from your instructor. Record the color, block number, and density using the
table below
AP Chemistry
Color of Block
Density (g/cm3)
Block number
Thin Grain Wood
0.75
1
Black
7.6
2
Copper
8.9
3
White
1.13
4
Thick Grain Wood
0.50
5
Clear
1.18
6
Silver
2.7
7
Grey
1.41
8
Thick Grain Wood
0.46
9
Gold
8.0
10
2. Measure the length, width, and height of the block as precisely as possible.
3. Find the actual mass of the block using an electronic balance if possible.
4. Repeat the procedure two times and average the values.
5. Repeat the procedure for two other blocks.
AP Chemistry
Name: ___________________________
Group Members:
___________________________
___________________________
___________________________
A MEASUREMENT CHALLENGE LAB REPORT FORM
Data
Create a data table that contains the data collected. Calculations for one trial must be shown. The
answers for the other trials may be reported without showing work.
Data Analysis
1. Calculate the volume of each block.
2. Calculate the mass of each block.
3. Using the actual mass and the predicted (calculated) mass, determine the percent error for
the mass of each block.
4. How successful were you at predicting the mass of each block? To what do you attribute
your success (or lack of success)?
5. How would the following errors affect the predicted mass of a block in this experiment?
(Would the predicted mass be higher, lower, or unchanged because of the error? Explain
your choice)
a. You accidentally recorded a length measurement as 7.50 cm instead of 8.50 cm.
b. You used a block that had a high amount of nicks and chips due to wear and tear.
AP Chemistry
c. You thought that a block belonged to the one type of wood instead of the correct
type of wood.
d. You forgot to zero the balance before you massed the block.
Conclusion