Percent Composition We Love math We use percents

Percent Composition We Love math! We use percents everyday!

Percentages o Do you understand percentages…. . o Your score on a quiz…. o Leave the tip for the waitstaff o Calculate the price in a sale item… o Percentages are important

Percentages o Calculate the percent of women in the classroom o Numerator = number of women in the class/ demoniator = number of total students in the classroom o Multiply by 100 = % women in class

Percents o You go to dinner and the bill is $ 44. 00. o You generously agree to leave the tip. o Of course you leave 20% for the waitstaff. o What is the tip? o $4. 40 + $4. 40=$ 8. 80 tip

Big Sale! o At the electronics store there is an i-pod marked $299. 99 SPECAIL SALE! o 30% off today!!!! o What is the sale price of this item? o $30+$30= $ 90 savings o 300 -90= $ 210 dollars is sale price

Percent Composition Chemistry o What is the percent mass of each element in water? Hydrogen 2( 1. 01 g)= 2. 02 g Oxygen 1(16. 00 g)= 16. 00 g total = 18. 02 grams

Water o % of Hydrogen 2. 02 grams/ 18. 02 grams times 100= 11. 2 % hydrogen in water ! o % oxygen 16. 00 grams/ 18. 02 grams times 100= 88. 8 % oxygen in water !

Glucose o C 6 H 12 O 6 o Carbon 6(12. 01 g) 72. 06 g o Hydrogen 12( 1. 01 g) 12. 12 g o Oxygen 6(16. 00 g 96. 00 g o total = 180. 18 grams

What is the percent mass of each element in glucose? o Carbon 72. 06 g/180. 18 g times 100 = 40 % o Hydrogen 12. 12 g/180. 18 g times 100 = 6. 7 % o Oxygen 96. 00 g/180. 18 g times 100 = 53. 3 %