(1)Aluminum reacts with oxygen to produce aluminum oxide according to the following reaction:

4Al(s) + 3O2(g) → 2Al2O3(s)
Calculate the moles of Al2O3 produced when the reaction is performed with 31.06 g of each reactant.

(2)Nitrogen dioxide reacts with water to produce nitric acid and nitrogen monoxide according to the following reaction:
3NO2(g) + H2O(g) → 2HNO3(g) + NO(g)
Calculate the moles of nitric acid produced when 46.79 grams of each reactant is used.

(3)Ammonia reacts with oxygen to produce nitrogen monoxide and water according to the following equation:
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l)
Calculate the moles of water produced in this reaction when 88.82 grams of each reactant are used.

(4)A rocket can be powered by the reaction of dinitrogen tetroxide (N2O4) and hydrazine (N2H4):
N2O4(l) + 2N2H4(l) → 3N2(g) + 4H2O(g)
A rocket was designed to hold 4.16 kilograms dinitrogen tetroxide and excess hydrazine. How much nitrogen gas in grams would be produced in this rocket?

2 answers

#1, 2, and 3 are limiting reagent problems. #4 is a plain vanilla stoichiometry problem.
Here are worked examples for both. Just follow the steps.

http://www.jiskha.com/science/chemistry/limiting_reagent_problem.html

http://www.jiskha.com/science/chemistry/stoichiometry.html
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