Name ______________________________
Period ________
LAB: Percentage of Sugar in Bubble Gum
Purpose
To determine the percentage of sugar in bubble gum.
Hypothesis
What is your prediction for the percentage of sugar in bubble gum? _________%
Materials
balance, bubble gum
Note: Chewed gum cannot be placed directly on the balance pan; it must be
wrapped in paper and the mass of the paper subtracted out.
1. Your teacher will give you one piece of bubble gum. Place the wrapped piece
of gum on the balance. Record the mass of the wrapper and unchewed gum.
2. Unwrap your piece of gum, and put the gum in your mouth. Do not throw the
wrapper away!
3. Place your empty gum wrapper on the balance. Record the mass of the
wrapper. Do not throw the wrapper away!
4. Chew your gum for 15 minutes.
5. After 15 minutes, place your gum back in its wrapper.
6. Place your wrapped, chewed gum on the balance. Record the mass.
7. Throw away the gum and wrapper.
Data
Mass (g)
Wrapper and unchewed gum
Wrapper only
Unchewed gum
Wrapper and chewed gum
Chewed gum
TURN OVER FOR ANALYSIS QUESTIONS!
Name ______________________________
Period ________
Analysis and Conclusions
1. What is the total mass of sugar that you removed by chewing? Assume that
ingested sugar accounts for the change in mass of the gum.
2. Calculate the percent error for the mass of sugar. Obtain the actual value for
the mass of sugar in one piece of gum from your teacher:
Actual value = ___________g
Experimental value = __________g
(use answer for #1 as your exp. value)
% Error = |Actual value – Experimental value| x 100
Actual value
3. (a) What is the percentage of sugar in a piece of gum?
Hint: % sugar =
Mass of sugar (from #1)
Mass of unchewed gum
x 100
(b)How did this compare to your predicted value?
(c) What assumption are we making when we calculate this percentage?
Hint: Do you think you removed anything else besides sugar when you
chewed the gum?
4. Would a lot of saliva trapped in the chewed gum cause the percentage of
sugar to appear higher or lower than it really is? Why?
Hint: Think about which measurement in the data table would be higher,
and what would that do to the answer to #1 above?
5. Assume that the sugar in the gum is sucrose, C12H22O11. Using the answer
from #1 above as a starting point, calculate the molecules of sugar that you
removed by chewing. Then calculate the total number of atoms in the sugar.