P ERCENT C OMPOSITION OF G UM L AB

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

L ESSON S EQUENCE 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

W ARM - U P How many formula units are in 5.6 g of H 2 S?

O BJECTIVE Today I will be able to: Determine the percent composition for each element in a compound Determine the percent composition of sugar in gum

H OMEWORK Finish Percent Composition Practice

A GENDA 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

P ERCENT C OMPOSITION Example What is the % composition of oxygen and hydrogen in water? Water = H 2 O = 18 g/mol 2 g H 2 18 g H 2 O x 100 =11.1 % Hydrogen 16 g O 18 g H 2 O x 100 = 88.9 % Oxygen

P ERCENT C OMPOSITION 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 x 100 =57.5 % 1.60 g O 4.00 g.100 g H 4.00 g x 100 = 40.0 % 2.50 %

P ERCENT C OMPOSITION 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?

P ERCENT C OMPOSITION 13.0% C 100 x.562 g =.0731 g C 2.20 % H % F 100 x.562 g =.0124 g H.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

E XIT T ICKET Write your percent composition of sugar in gum on the board. We will discuss the results as a class