Chemistry brooks

Chemistry-Brooks

February 9, 2012

NOTES FROM TODAY!!!!

Percent Composition =      Part       x 100

                                            Total     

For percentages= only write two decimal places.

1.     Find the Molar Mass

2.     Get the total

3.     Then do each step

1.     What is the percent composition of KClO₃?

Molar Mass of KClO₃

K= 39.01 x1 = 39.10 (Part)         39.10/122.55 x 100 =        

Cl= 35.45 x 1 = 35.45 (Part)        35.45/122.55 x 100 =

O3= 16.00 x 3= 48.00 (Part)        48/122.44 x 100 =

                                 Total 122. 55                 100.01%

2.     What is the percent composition of HNO₂?

Molar Mass of HNO₂

H= 1.01 x 1 = 1.01                  1.01/47.02 x 100   = 2.15 %

N= 14.01 x 1 = 14.01              14.01/47.02 x 100 = 29.80%

O₂= 16.00 x 2 = 32.00                        32.00/47.02 x 100 = 68.06 %             

                              Total  47.02                                     100.01%

3.     What is the percent composition of Iron III sulfate?

4.     What is the percent composition of heptane? C7H16

5.     What percent of K₃PO₄ is potassium?

a.     What percent is phosphorus?

b.     How many grams of potassium are in 10.48g of K₃PO₄?

117.30 / 212.27 x 10.48g = 5.791228 (How many sf) 5.791 g K

K3 = 39.10 x 3 = 117.3

P = 30.97 x1 = 30.97

O4 = 16.00 x 4 = 64.00