1. Drill
What is the relationship between particles and mass in a substance?

2. Objective The student will be able to:
Use molar mass (formula mass) in order to calculate % composition.

3. SAT/HSA Enrichment
The number of grams in 1.5 x 1025 molecules of CO2 are

4. Percent Composition and Chemical Formulas
How much Sugar is in Bubble Gum?

5. Engagment What is in bubble gum? Discussion
How can we find the amount of sugar in the bubble gum.
Generate a list of ideas on the board.

6. Percent Composition and Chemical Formulas
It helps to know the percents of the components in a shirt because they affect how warm it is, whether it will need to be ironed, and how it should be cleaned. You will learn how the percents of the elements in a compound are important in chemistry.

7. The Percent Composition of a Compound
The percent by mass of an element in a compound is the number of grams of the element divided by the mass in grams of the compound, multiplied by 100%.

8. Percent Composition from Mass Data
The relative amounts of the elements in a compound are expressed as the percent composition or the percent by mass of each element in the compound.

9. Percent Composition from Mass Data
The relative amounts of the elements in a compound are expressed as the percent composition or the percent by mass of each element in the compound.

10. Percent Composition from the Chemical Formula

11. Percent Composition as a Conversion Factor
You can use percent composition to calculate the number of grams of any element in a specific mass of a compound.

12. The Percent Composition of a Compound
Propane (C3H8) is 81.8% carbon and 18% hydrogen. You can calculate the mass of carbon and the mass of hydrogen in an 82.0 g sample of C3H8.

13. Molecular Formulas

14. Quick Quiz
1. Calculate the percent by mass of carbon in cadaverine, C5H14N2, a compound present in rotting meat.
67.4% C
58.8% C
51.7% C
68.2% C

15. Bite the Bubble 30 min Purpose:
Determine the percent mass of sugar in bubble gum.
To complete the lab and the problems.
Place paper in the bin when finished.
30 min

16. Percent Composition Complete problems 1-2 as class.
Work with your partner (person next to you) to complete problems 3-8.
Review answers as a class.

17. Summary Did we accomplish the objective? Explain.
Determine the equation used to determine the percent composition of an element.
Identify the steps used to determine the percent composition of an element.
What does the total percent composition of a compound equal?
Summarize the main idea of today’s lesson.

18. Homework
Percent Composition worksheet.