Mass/Volume Ratio
Central Bucks Chemistry Laboratory Manual
Pre-Lab
http://tinyurl.com/cbchemlab-massvolume
Context
true that 1 ml of water = 1 cm3. A solid
object placed immersed in water causes the
water level to rise because the object
displaces an equal volume of water.
Goals
 Collect mass and volume data for
samples of different pure
substances.

Analyze the data
for evidence of a
mathematical
relationship
between the mass
and volume of each
substance.
1) Obtain the mass of the
sample and its container.
2) Use water
displacement to determine the
volume of the sample.
Record a precise volume
before and after the sample is
added.
Text Reference

Prentice Hall Chemistry: 3.3
3) Obtain the mass of the empty
container.
All experimental measurements have
uncertainty. Reliability in science comes
with reproducibility. Though observations
and inferences can be made using one
sample, conclusions are made after
examining large amounts of data. In this lab,
you will collect individual data and combine
it with data collected by your peers to
discover a pattern. Two common properties
measured in chemistry are mass and volume.
Mass is defined as the amount of matter in a
sample. Volume is defined as the amount of
space occupied by a sample. We can
measure an object and calculate its volume
using an appropriate geometric formula such
as, “area of the base x height”. But if the
object has an irregular shape we use the
method of water displacement. It is always
You are going to create a graph that includes
data for all of the samples analyzed in your
class. The mass and volume data from each
lab group will represent one ordered pair (x,
y) on your scatter plot.
#3- Mass/Volume Ratio / 1
1) Prepare a graph of mass (y-axis) vs.
volume (x-axis). Mass should be
expressed in grams, and volume should
be expressed in cubic centimeters (cm3).
Scale each axis thoughtfully, as you
need to fit the class data for both
substances on the scatter plot as pictured
in Figure 1.
2) Revisit the equation for slope.
a. How do the variables in this
equation relate to the measurements
made in the lab and the ordered pairs
on the graph? (Hint: What do “x”
and “y” represent? Think
specifically about the unit of each.)
b. What physical property is revealed
by the slope?
3) Using both quantitative and qualitative
observations:
Figure 1. Unlabeled scatter plot containing
two substances
2) Plot the class data for the first
substance.
3) Draw a trendline that describes the
entire data set. Do not connect the dots.
4) Identify the equation for the treadline.
a. Determine the likely identity of each
substance. What evidence was used
in each case? Document any
resources that you used.
b. Using an accepted value for density,
calculate a percent error for each
substance.
4) Use your trendline and equation to make
the following predictions:
5) Calculate the slope of the trendline.
This can be done in multiple ways.
a. Predict the volume of exactly 20.00g of each substance.
6) Repeat steps #2-5 for the second
substance. Do this on the same scatter
plot, but be sure to mark the new points
differently. Note the difference in
Figure 1.
b. Predict the mass of exactly 2.50-cm3
of each substance.
1) What does the class data show about the
relationship between mass and volume
for each substance?
2 / #3 Mass/Volume Ratio
Test your predictions by recalculating
the respective volumes and masses
using published accepted density values
for both substances.
5) Calculate the density of each substance
using the specific mass and volume
values that your group collected.
Compare these values with the density
values obtained from the trendline.
What is the advantage of calculating the
densities using the class data?
3) Application Questions
 Complete 1-5 in the “Discussion /
Conclusions” section.
1) Experiment
Students collected the following data
using the same lab procedure for two
unknown substances:
Mass
(g)
64.0
55.1
25.5
31.6
45.7
18.7
20.0
38.5
47.5
35.0
27.5
55.5
18.7
15.7
66.4
13.8
9.0
60.0
42.6
25.5
40.3
62.5
19.0
22.5
22.4
69.3
62.2
Volume
(ml)
8.0
7.5
9.2
4.7
5.8
6.5
8.1
5.2
6.7
7.2
8.6
6.7
6.7
5.6
8.9
6.6
4.3
8.6
6.3
7.6
4.9
7.7
9.5
7.9
8.8
9.0
7.4
 Body fat percentage can be
determined using water displacement.
Especially in the case of collegiate
athletes, this information is useful in
designing training programs.
Research the technique and address
each of the following prompts in a
multi-paragraph essay:
 What is the formula for the
volume of the following shapes?
(rectangular prism, sphere,
cylinder)
 How is the volume of an irregular
object like the human body
measured?
 Describe the technique that is
used to determine body fat
percentage.
PhET Density Simulation
Interactive activity involving miscellaneous
objects and a pool of water
Simulation found at:
http://tinyurl.com/cbchemlab-densitysimulation
Writing Activities and Prompts
Qualitative Observations
Samples were made up of two different
solids, both metals.
 Substance #1: Dull gray-colored
 Substance #2: Shiny silver-colored
2) Analysis
 Complete 1-6 in the “Analysis”
section.
1) Student Experimentation
Design your own experiment to answer
any of the following driving questions.
In each case, students should provide:
 Numbered / bulleted list to describe
procedure
#3- Mass/Volume Ratio / 3
 Specific evidence from simulation:
 Data table
 Qualitative observations
 Written conclusions
I.
II.
III.
IV.
V.
Consider the statement: “Bigger is
always heavier.” When is this
true? When is it untrue?
What is the density of the liquid?
What conditions must occur for an
object to float? When will it float
above the surface? Below the
surface? Sink to the bottom?
Change the “Blocks” menu to
“Mystery.” Determine the identify
of each block, A-E.
Pick your own driving question.
Be sure to clearly indicate the
question before you provide your
procedure, data, and conclusions.
2. Create an activity for a peer that
requires the use of the simulation. On
a separate sheet, provide an answer key
that indicates anticipated results and/or
correct answers.
Related Links
Units
Converting between different units of
measurement
http://tinyurl.com/cbchemlab-units
http://tinyurl.com/cbchemlab-units2
Standards
Defining units of measure
http://tinyurl.com/cbchemlab-standards
http://tinyurl.com/cbchemlab-standards2
4 / #3 Mass/Volume Ratio
Related Careers / Fields of Study
X-Ray Cyrstallography
Determining the arrangement of atoms in a
crystal
 An x-ray crystallographer studies
diffraction patterns that result when
x-rays pass through a crystal lattice
 An informational site devoted to the
technique:
http://tinyurl.com/cbchemlab-crystallography

Search terms: x-ray crystallography,
x-ray diffraction, crystal lattice, unit
cell, diffractometer
Polymer Chemistry
Joining small molecules in a repeating chain
to form products with useful properties
 A wide variety of natural and
synthetic molecules are classified as
polymers
 Notable examples include: Plastics
(PP, HDPE, LDPE, PVC, PETE,
etc.), polysaccharides, nylon, rubber,
etc.
 Search terms: Polymer,
polymerization, monomer,
crosslinking, polymer degradation
American Chemical Society. (2011). Polymer chemistry
[Careers in chemistry]. Retrieved from
http://portal.acs.org/portal/acs/corg/content?_nfpb=
true&_pageLabel=PP_ARTICLEMAIN&node_id=
1188&content_id=CTP_003399&use_sec=true&se
c_url_var=region1&__uuid=ce344f75-7c57-42588ab9-f0a85bbcceb1
Davis, J. E., MacNab, W. K., McClellan, A. L., &
O’Connor, P. R. (1982). Chemistry: Experiments
and principles. Lexington, Massechusetts: Heath.
Hayden, M. (2008). X-ray crystallography. Retrieved from
http://www.sas.upenn.edu/~mhayden/mcep/chem5
07/project/crystallography.html
Wilbraham, A., Staley, D., Matta, M., & Waterman, E.
(2008). Chemistry. Boston, Massachusetts: Pearson
Prentice Hall.