1. Percent Composition of Gum Lab

2. Evaluation/Assessment:
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

3. Lesson Sequence Evaluate: Warm – Up
Engage and Explore: Percent Composition of Gum Lab
Explain: Percent Composition Notes
Elaborate: Percent Composition Practice
Evaluate: Exit Ticket

4. Warm-Up
An organic compound with a molecular mass of 140 g/mol is 68.54% carbon, 8.63% hydrogen, and 22.83% oxygen.
What is the molecular formula of the compound?

5. 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

6. Homework Finish Percent Composition Practice
Start studying for quiz on Monday 3/17!!!

7. Agenda Warm-Up Percent Composition Notes
Percent Composition of Gum Lab
Percent Composition Practice
Exit Ticket

8. Percent Composition Notes

9. 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

10. 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

11. Percent Composition Example:
What is the % composition of oxygen and hydrogen in water?
Water = H2O = 18 g/mol
2 g H2
18 g H2O
x 100 =
11.1 % Hydrogen
16 g O
18 g H2O
88.9 % Oxygen
x 100 =

12. Percent Composition
Q: Find the % composition of a compound that contains 2.30 g sodium, 1.60 g oxygen, and g hydrogen in a 4.00 g sample of the compound?
2.30 g Na
4.00 g
1.60 g O
4.00 g
x 100 =
40.0 %
x 100 =
57.5 %
.100 g H
4.00 g
x 100 =
2.50 %

13. 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?

14. Percent Composition 100 x .562 g = .0731 g C 2.20 % H 100 x .562 g =
.0124 g H
84.8 % F
100
x .562 g =
.477 g F

15. Percent Composition Lab

16. 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

17. Percent Composition Practice
Complete the practice at your desk. Problems not completed in class will become your homework.

18. Exit Ticket
Write your percent composition of sugar in gum on the board.
We will discuss the results as a class