PERCENT COMPOSITION OF GUM
LAB

Objective:

Today I will be able to:
Determine the percent composition for each element in a compound
 Determine the percent composition of sugar in gum


Evaluation/Assessment:



Informal assessment – monitoring student interactions as
they complete the gum lab and the practice
Formal assessment – analyzing student responses to the
gum lab, the practice and the exit ticket
Common Core Connection
Make sense of problem and persevere in solving them
 Look for and express regularity in repeated reasoning
 Attend to precision
 Use appropriate tools strategically

LESSON SEQUENCE
Evaluate: Warm – Up
 Evaluate: Review HW
 Engage and Explore: Percent Composition of
Gum Lab
 Explain: Percent Composition Notes
 Elaborate: Percent Composition Practice
 Evaluate: Exit Ticket

WARM - UP

Predict the products of the following reaction:


KClO3 
If 2.3 grams of KClO3 are used to decompose a
gummy bear, what volume of CO2 will be
produced?
OBJECTIVE

Today I will be able to:
Determine the percent composition for each element
in a compound
 Determine the percent composition of sugar in gum

HOMEWORK
Finish Percent Composition Practice
 Mole Project Due Tuesday, March 11

AGENDA
Warm-Up
 Review HW
 Percent Composition Notes
 Percent Composition of Gum Lab
 Percent Composition Practice
 Exit Ticket

REVIEW HW
Once the problems have been reviewed, the HW
will be collected
PERCENT COMPOSITION
NOTES
BEFORE WE BEGIN - LAB SET-UP
To calculate the percent composition of sugar in
gum
 First you need the mass of your gum before you
chew it

Take the mass
 Chew the gum as we take notes
 DO NOT THROW AWAY THE WRAPPER

WHAT IS PERCENT COMPOSITION?

Percent Composition – is the mass of each
element in a compound compared to the entire
mass of the compound x 100
PERCENT COMPOSITION
Example
 What is the % composition of oxygen and hydrogen in
water?
 Water = H2O = 18 g/mol

2 g H2
18 g H2O
16 g O
18 g H2O
x 100 =
11.1 % Hydrogen
x 100 =
88.9 % Oxygen
PERCENT COMPOSITION

Find the % composition of a compound that contains
2.30 g sodium, 1.60 g oxygen, and .100 g hydrogen in a
4.00 g sample of the compound?
2.30 g Na
4.00 g
.100 g H
4.00 g
x 100 = 57.5 %
x 100 =
2.50 %
1.60 g O
x 100 =
4.00 g
40.0 %
PERCENT COMPOSITION

A sample of an unknown compound with a mass
of .562 g has the following % composition: 13.0%
carbon, 2.20% hydrogen, and 84.8% fluorine.
When this compound is decomposed into its
elements, what mass of each element would be
recovered?
PERCENT COMPOSITION
13.0% C
100
2.20 % H
100
84.8 % F
100
x .562 g =
.0731 g C
x .562 g =
.0124 g H
x .562 g =
.477 g F
PERCENT COMPOSITION
LAB
LAB DIRECTIONS
Mass your chewed gum. Be Sure to put the
wrapper down on the balance first
 Complete the calculations and the questions


When you finish, you may begin working on the
percent composition practice worksheet
PERCENT COMPOSITION
PRACTICE
Complete the practice at your desk. Problems not
completed in class will become your homework.
EXIT TICKET
Write your percent composition of sugar in gum
on the board.
 We will discuss the results as a class
