1. Percent Composition What is percent composition? How do I relate percent composition to counting concepts? How do I calculate percent composition?

2. Percent Composition = % (by mass) of each element in the compound = part / whole Free Throw Percentages: Shooting% = _# shots made_ x 100 # of shots taken Ex. make 13, take 17 ( 13 / 17 ) x 100 = 76.5% Ex. make 9, miss 5 ( 9 / 14 ) x 100 = 64.3%

3. Bill, Bill, Bill, Bill …. T-shirt! Bill bought a new shirt and it has: 65% Polyester 35% Cotton + 100% T-shirt If I had 100 g of t- shirt, how many grams would be cotton?

4. Percent Composition When a 13.6 g sample of a compound containing magnesium and oxygen is decomposed, 5.4 g of oxygen is obtained. What is the % composition?

5. Percent Composition Propane (C 3 H 8 ), commonly used in grills, is one compound obtained from petroleum. Calculate the % composition of propane.