Chapter 9 Test - Ms. Tabors Classroom

name: ____________________
date: __________
Stoichiometry Test
Show all work, and including units for full credit. Circle your answers.
Make sure all equations are balanced before you do the math!
1) What is the mass, in grams, of 4.38 x 1024 atoms of carbon?
2) 2Al2O3(l)  4Al(s) + 3O2(g)
How many moles of aluminum are produced by the decomposition of 9.75 moles of aluminum oxide?
3) SiO2(s) + 4HF(aq)  SiF4(aq) + 2H2O(l)
What mass, in grams, of silicon tetrafluoride (SiF4) is produced when 2.27 mol of hydrofluoric acid
reacts with silicon dioxide?
4) 2C2H2(g) + 5O2(g)  4CO2(g) + 2H2O(g)
(a) How many grams of carbon dioxide would be formed when 824.9 g of acetylene (C2H2(g)) burns
(b) How many molecules of oxygen would be required for this combustion?
5) 2Fe(OH)3(aq) + 3H2SO4(aq)  Fe2(SO4)3(aq) + 6H2O(l)
(a) If 37.5 grams of iron (III) hydroxide react with 50.0 grams of sulfuric acid, what is the limiting
(b) What is the limiting reactant and excess reactant?
6) What are the conditions of standard temperature and pressure?
7) Consider a small cylinder in the lab filled with chlorine gas. If the cylinder has a volume of 4.75L,
how many grams of Cl2(g) would it contain at STP?
name: ____________________
date: __________
8) Aluminum reacts with hydrochloric acid according to the following equation:
2Al(s) + 6HCl(aq)  2AlCl3(aq) + 3H2(g)
If 35.0g of Al are combined with 63.0g HCl, what mass of aluminum chloride is produced?
2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(g)
If 320. g of octane (C8H18) are burned and 392 g of water are recovered, what is the percent yield of
the experiment?
10) Liquid carbon disulfide reacts with 3.25 L of oxygen gas at STP to produce carbon dioxide
and sulfur dioxide according to the following balanced equation:
CS2(l) + 3O2(g)  CO2(g) + 2SO2(g)
(a) What volume of CO2 is produced?
(c) What mass (in g) of SO2 is produced?
Part 2:
11) An oxide of Chromium is found to have the following percent composition: 68.4% Cr and 31.6% O.
Determine this compound’s empirical formula.
name: ____________________
date: __________
12) The empirical formula for trichloroisocy acid (the active ingredient in many household bleaches) is
OCNCl. The molar mass of this compound is 232.41g/mol. What is the molecular formula for
trichloroisocy acid?
13) The molar mass of nicotine is 162.1 g/mol. It contains 74% carbon, 8.7% hydrogen and 17.3%
nitrogen. Determine nicotine’s empirical formula and molecular formula.
14) What is the percent yield of silver bromide if 10.79 g of silver bromide is formed from the reaction of
7.65 g of potassium bromide with 9.89 g of silver sulfate?