Question #1

nitric acid is produced from ammonia and oxygen by the following consecutive reactions:

4 nh3(g) + 5 o2(g) → 4 no(g) + 6 h2o(g)

2 no(g) + o2(g) → 2 no2(g)

3 no2(g) + h2o(l) → 2 hno3(aq) + no(g)

how many grams of nitric acid can be produced from 100.0 g each of ammonia and oxygen, given that the second reaction has a 90% yield (assume 1st and 3rd reactions are quantitative, i. e. 100% yield)?

question #2

a mixture of sodium chlorate and sodium chloride is heated. the sodium chlorate decomposes to sodium chloride and oxygen gas. if 2.235 g of the mixture is heated and the resulting solid product has a mass of 1.875 g, what is the percentage of sodium chloride in the original mixture?

question #3

mixing some aqueous barium hydroxide with 50.0 g of sodium sulfate gives a reaction with a 67% yield of solid product. the barium hydroxide solution (100. ml) supplied was titrated using 76.3 ml of a phosphoric acid solution. knowing that 10.0 ml of the phosphoric acid solution was previously standardized with 20.22 ml of a 5.00 m naoh solution, what volume of aqueous barium hydroxide is needed and how much solid is produced?

question #4

calculate the energy required to bring 25.0 g of methanol (ch3oh) from -75.0 °c to +150.0 °c. the specific heat of methanol is 19.5 cal/g∙k in the liquid state and 10.5 cal/g∙k in the gas state. methanol has a melting point of -97.9°c, a heat of fusion of 99.6 j/g, a boiling point of 65.15°c and a heat of vaporization of 9.7 kj/g.

 

question #5

given the following information:

b2o3(s) + 3 h2o(g) → b2h6(g) + 3 o2(g) h° = +2035 kj

2 h2o(l) → 2 h2o(g) h° = +88.0 kj

h2(g) + ½ o2(g) → h2o(l) h° = –286.0 kj

2 b(s) + 3 h2(g) → b2h6(g) h° = +36.0 kj

determine the h for the reaction:

2 b(s) + 3/2 o2(g) → b2o3(s)

question #6

automobile air bags are inflated by the decomposition of sodium azide (nan3) to sodium metal and nitrogen gas. the reaction is highly exothermic (–43.4 kj/mol nan3). if the air bag is inflated to a volume of 65 l at a pressure of 1.75 atm and a temperature of 15.0 °c, what amount of heat will also be produced?