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Percent Composition of Sugar in Bubble Gum Lab
Have you ever looked on a package of bubble gum to see what it is made of? Bubble gum is made of two different
types of saps collected from trees. The first type of sap, chicle, comes from the sap of the sapodilla or naseberry tree
(not raspberry). This tree grows in Mexico, Central America, and tropical sections of South America. The second
type of sap, gutta siak is a rubber-like sap obtained from trees that grow in the Netherlands. This sap was found to be
fun to chew, and you could probably blow bubbles with this sap just as it comes from the tree! Incidentally, sap is
collected by making cuts at the bottom of the tree, and then collecting it in cups. The sap is later processed into the fun
treat we know and love – bubble gum!
Packaged foods, such as bubble gum, are required by law to list all ingredients but not the exact amounts of them. The
ingredients are listed in order of largest amount to smallest. (The first ingredient makes up the biggest part of the food.)
The actual amounts of each ingredient are protected as business secrets. In this lab experiment you will determine the
ACTUAL mass of sugar in your gum, and the PERCENT COMPOSITION BY MASS of sugar in your gum.
When you make a new compound in the laboratory, you need to determine its formula. One of the first steps in doing
this is to find the relative amounts of the elements in the compound. These relative amounts are expressed as the
percent composition—the percent, by mass, of each element in a compound. The percent by mass of an element in a
compound is the number of grams of the element divided by the grams of the compound, multiplied by 100%:
% mass of element E = grams of element E x 100%
grams of compound
The percent composition of a compound has as many percent values as there are elements in the compound. These
percentages must add up to 100%.
Purpose: The purpose of the lab is to calculate the percent of sugar found in bubble gum using percent composition
(also called percent by mass) calculations. Lab data will be used to apply the factor-label method in solving mole
problems.
Materials Needed:
Triple beam balance
Bubble Gum
Safety Precautions and Cleanup: Gum is NOT to be
placed directly on the balance. Gum will be placed on
wrappers. Do not put gum in mouth if it gets dirty
(duh- but you never know…). Finally, chewed gum
belongs in the trash at the end of the lab – NOT
underneath a desk (or on the bottom of someone’s
shoe!)
Procedures:
Each lab partner will follow the procedure below:
1. Mass the bubble gum in its wrapper. Save the wrapper. Remember to measure to the nearest 0.01g.
2. Unwrap the gum and place it in your mouth. Find the mass of the wrapper.
3. Calculate the mass of the unchewed gum.
4. Chew the gum until the flavor is gone, around 20 minutes.
5. After 20 minutes, carefully blot the gum dry with a paper towel. Avoid getting the gum stuck to the paper towel.
6. Mass the chewed gum in its original wrapper.
7. Calculate the mass of sugar in the gum. (The mass of the other flavorings is negligible.)
8. Use your lab partner’s data for trial 2.
Name: ______________________________________ Period: _______________ Date: ________________
Data Table (all masses must be to 0.01g):
Measurement
Trial 1
Trial 2
Average
Mass of gum and wrapper (g)
Mass of wrapper (g)
Mass of unchewed gum (g)
Mass of gum and wrapper after chewing (g)
Mass of gum after chewing (g)
Mass of sugar in gum (g)
Percent composition of sugar in gum (%)
Calculations (use significant figures, show all equations - factor-only, use units after all numbers):
1. For each trial, calculate the percent of sugar in your gum.
2. What is the average percent of sugar in your gum? How did this compare with your classmates? (class average is
75.0%)
3. There are 4.1 Calories per gram of sugar. How many Calories do you get from chewing one piece of gum? Use the
equivalency 4.1 Calories = 1 gram to make your conversion factor. Begin your equation with the average number of
grams of sugar from the gum you chewed in class.
4. A 5 pound bag (2.26 kg) bag of sugar costs approximately $2.00. How many pieces of gum could be produced from
this amount of sugar? Continue to use the average number of grams of sugar from today’s lab.
5. If the bubble gum sells for 5 cents per piece, how much money would be generated by the sale of the gum produced
from a 5 pound bag of sugar?
6. Assume that the formula of the sugar in the gum is C12H22O11. Calculate the following using the average number of
grams of sugar from the gum you chewed in class:
a. Molar mass of sugar
b. Moles of sugar in chewing gum
c. Molecules of sugar in chewing gum
d. Percent of chewing gum sugar that was made of carbon (by mass)
e. Percent of chewing gum sugar that was made of hydrogen (by mass)
f.
Percent of chewing gum sugar that was made of oxygen (by mass)