#15 How many molecules of oxygen are produced by the decomposition of 6.54 g of potassium chlorate

1. #15 How many molecules of oxygen are produced by the decomposition of 6.54 g of potassium chlorate 2KClO3  2KCl + 3O2 6.54 g KClO3 (given) ? molecules produced 1 mole KClO3 X 122.55 g KClO3 3 molesO2 2 mole KClO3 6.54 g KClO3 X 1 x 6.02 x 1023molecules O2 1mole O2 = 4.82 x 1022 molecules O2 16 +16 +16+ 35.45 + 39.1 = 122.55 molar mass of KClO3

2. #16 The last step in the production of nitric acid is the reaction of nitrogen dioxide with water. 3NO2 + H2O  2HNO3 + NO 5.00 x 1022 molecules NO (given) ? g NO2 1 mole NO x 6.02 x 1023 molecules NO 5.00 x 1022 molecules NO x 1 3 molesNO2 x 1 mole NO 46 g NO2 1mole NO2 = 11.5 g NO2 16 +16 +14 = 46 molar mass of NO2

3. #17 The equation for the combustion of carbon monoxide is: 2CO + O2 2CO2 How many liters of Oxygen are required to burn 3.86 L of carbon monoxide? 2CO + O2 2CO2 3.86 L CO ? L O2 1 mole CO x 22.4 L CO 1 mole O2 x 2 mole CO 22.4 L O2 1 mole O2 3.86 L CO x 1 = 1.93 L O2

4. #18 Phosphorus and hydrogen can be combined to form phosphine (PH3) P4(s) + 6H2(g) 4PH3(g) How many liters of phosphine are formed when 0.42 L of hydrogen reacts with phosphorus? P4(s) + 6H2(g) 4PH3(g) ? L PH3 0.42 L H2 0.42 L H2 x 1 1 mole H2 x 22.4 L H2 4 moles PH3 x 6 moles H2 22.4 L PH3 1 mole PH2 = 0.28 L PH3

5. #19 Consider this equation: CS2 + 3O2 CO2 + 2SO2 27.9 mL O2 ? L SO2 (the only trick here is to convert to liters from mL and the rest of the problem is the same) 27.9 mL O2 x 1 1 L O2 x 1000 mL O2 1 mole O2 x 22.4 L O2 = .018 L SO2 18.6 mL SO2 2 moles SO2 x 3 moles O2 22.4 L SO2 1mole SO2

6. #20 Consider this equation: CS2 + 3O2 CO2 + 2SO2 ? dL CO2 0.38 L SO2 (the only trick here is to convert to deciliters from Liters) 1 dL is 100 ml or 1/10 of a liter 0.38 L SO2 x 1 1mole SO2 x 22.4 L SO2 1 mole CO2 x 2 moles SO2 = 1.9 dL CO2 .19 L CO2 22.4 L CO2 x 1 moles CO2 10 dL CO2 1 L CO2