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AP Chemistry
Formulas ~ 1
Name: ________________________________
1. Calculate the simplest formula for a compound containing 75.7% As and 24.3% O.
2. Combustion of 200.0 mg of a hydrocarbon (a compound containing only carbon and
hydrogen) results in 600.0 mg of carbon dioxide and 327.27 mg of water.
a) What is the empirical formula of the compound?
b) Write and balance a chemical equation for the combustion of this compound.
3. Combustion of 100.0 mg of a compound containing only carbon, hydrogen, and oxygen results
in 227.59 mg of carbon dioxide and 93.103 mg of water.
a) What is the empirical formula of the compound?
b) If the molecular weight lies between 100 and 200 g, what is the molecular formula?
4. Cocaine, a drug extracted from cocoa leaves, contains C, H, O, and N. Combustion of 3.000
mg of cocaine produces 7.406 mg of CO2, 1.871 mg of H2O, and 0.1386 mg of N2.
a) Calculate the number of moles each of CO2, H2O, and N2 produced by the combustion.
b) How many mg and how many moles of dioxygen gas were used in the combustion
reaction?
c) Determine the simplest formula for cocaine.
d) Write and balance a chemical equation for the combustion of cocaine.
5.
3.40 g of dihydrogen and 7.16 g of dinitrogen react to form gaseous ammonia.
a) Write and balance the chemical equation.
b) What is the limiting reactant?
c) What is the theoretical yield of ammonia in grams?
d) How many moles of excess reactant remain unreacted?
e) If the actual yield in part c) is 87.5%, how many grams are produced?