Name: _______________
Date:
_______
level 3 chemistry – chapter 10 & 11 review sheet – ‘the
mole’ and ‘stoichiometry’
1. Key vocabulary terms to be familiar with:
2.

molar mass

actual yield

Avogadro’s number

theoretical yield

molar volume

conservation

mole

empirical formula

excess reactant

molecular formula

limiting reactant

STP

percent composition

percent yield

carbon-12
Calculate
of
mass/matter
the
percent
composition,
by
mass,
for
the
following
compounds:
a. phosgene, COCl2
b. bromoform, CHBr3
c.
phosphorous
oxychloride, POCl3
3. Vitamin C is composed of 40.92 % carbon, 4.58 % hydrogen, and
54.50 % oxygen, by mass. It has a molar mass of 176.12 g/mol.
a. Determine vitamin C’s empirical formula.
b. Determine vitamin C’s molecular formula.
4. A compound containing boron and hydrogen has the composition 6.444
g of B and 1.803 g of H. The molar mass of this compound is 30.00
g/mol. Calculate the molecular formula.
5. An elemental analysis of a compound gives the following percent
composition by mass:

C, 44.4 %

H, 6.21 %

S, 39.5 %

O, 9.89 %
a. Calculate its empirical formula.
b. Calculate its molecular formula given that its molar mass is about 162
g/mol.
6. How many grams of water can be formed when 4.22 liters of ethane
(C2H6) combust in oxygen?
7. How many liters of carbon dioxide can be produced (at STP) by
decomposing 47.4 grams of calcium carbonate according to the following
reaction?
CaCO3  CaO + CO2
8. When iron (II) hydroxide is mixed with phosphoric acid, iron (II)
phosphate precipitate results.
3Fe(OH)2 + 2H3PO4 → Fe3(PO4)2 + 6HOH
a. If 6.40 g of Fe(OH)2 is combined with 5.60 g of phosphoric acid,
what is the limiting reagent and what is the reactant in excess?
b. How many grams of Fe3(PO4)2 precipitate can be formed?
c. If 2.75 g of Fe3(PO4)2 is actually obtained, what is the percent
yield?
9. For the reaction:
Na2O + H2O  2NaOH
a. What mass of NaOH could be made from 12.4 g of Na2O and 42.1 g of
H2O?
b. What would be the limiting reactant if 100 g each of Na2O and H2O
were allowed to react?
10. Consider the following reaction:
CaCO3 + 2HCl  CaCl2 + CO2 + H2O
a. Excess hydrochloric acid was reacted with 8.57 g of calcium carbonate
and produced 3.11 g of CO2. Calculate the percent yield?
b. In a second experiment, using 9.21 g of calcium carbonate, 1.90 L of
CO2 was collected. Calculate the percent yield?