Name: _______________________________ Hour: __________
Capstone 4 Review
Moles
1. 1 mole = _________________ molecules/particles/things
2. How many moles of H2 are needed in the reaction 2H2 + O2  2H2O
Molar Mass
For each of the following, calculate the molar mass.
1. BF3
2. CCl2F2
3. Ca(C2H3O2)2
Molar Conversions
1. What is the mass of 1 mole of Barium acetate, Ba(C2H3O2)2?
2. What is the molar mass (g/mol) of cyclohexanol, C6H11OH?
3. How many moles are in 2.35 g of H2O?
4. If we have 0.072 g of FeCl3 then how many moles are there?
Percent Composition
1. CuBr2
Total molar mass:
Mass due to Cu:
Cu: ___________
Mass due to Br:
Br: ___________
2. NaOH
Na: ___________
O: ___________
H: ___________
H: ___________
S: ___________
3. (NH4)2S
N: ___________
Empirical Formulas
1. Dr. Barry Um has a sample of a compound, which weighs 200 grams and contains only carbon,
hydrogen, oxygen and nitrogen. By analysis, he finds that it contains 97.56 grams of carbon, 4.878 g
of hydrogen, 52.03 g of oxygen and 45.53 g of nitrogen. Find its empirical formula.
Convert grams to moles for each element in the compound:
Find the smallest number of moles:
Divide all molar amounts by the smallest number of moles:
Round:
Use the rounded numbers as coefficients: C
H O N
2. The characteristic odor of pineapple is due to ethyl butyrate, an organic compound, which contains
only carbon, hydrogen and oxygen. If a sample of ethyl butyrate is known to contain 0.62069 g of
carbon, 0.103448 g of hydrogen and 0.275862 g of oxygen, what is the empirical formula for ethyl
butyrate?
3. 300 grams of a compound, which contains only carbon, hydrogen and oxygen is analyzed and found to
contain the exact same percentage of carbon as it has oxygen. The percentage of hydrogen is known
to be 5.98823%. Find the empirical formula of the compound.
Molecular Formulas – solve for the molecular formula and/or empirical formula as
needed.
1. A compound with an empirical formula of CFBrO and a molar mass of 254.7 grams per mole.
Molar mass of the empirical formula:
Molar mass of empirical formula/molecular mass:
Round:
Multiply by the subscripts:
Formula:
2. A compound with an empirical formula of C2H8N and a molar mass of 46 grams per mole.
3. A well-known reagent in analytical chemistry, dimethylglyoxime, has the empirical formula C2H4NO. If
its molar mass is 116.1 g/mol, what is the molecular formula of the compound?
4. What’s the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0%
oxygen?
Stoichiometry
1. Mole to Mole You have 30 moles of K2CO3. Given the following equation, how many moles of CO2
could be produced?
4 FeCr2O7 + 8 K2CO3 + 1 O2  2 Fe2O3 + 8 K2CrO4 + 8 CO2
2. Mole to Gram You have 7.2 moles of Al. Given the following reaction, how many grams of H2 could
be produced?
6 NaOH + 2 Al  2 Na3AlO3 + 3 H2
3. Gram to Mole You have 250g of FeCr2O7. Given the following equation, how many moles of Fe2O3
would be formed?
4 FeCr2O7 + 8 K2CO3 + 1 O2  2 Fe2O3 + 8 K2CrO4 + 8 CO2
4. Gram to Gram You have 16g of NaOH. Given the following reaction, how many grams of Na3AlO3
could you produce?
6 NaOH + 2 Al  2 Na3AlO3 + 3 H2
5. Under standard conditions, determine the maximum volume of carbon dioxide, CO2, that could be
produced when 30g of butane (C4H10), completely reacts in an excess amount of oxygen.
[Hint: 1 mole of any gas under standard conditions occupies 22.4L of volume.]
2 C4H10 + 13 O2  10 H2O + 8 CO2
Limiting Reactants
1. What is a limiting reactant?
2. Consider the following synthesis reaction: 2H2 + O2  2H2O. If we had 10 moles of H2 and 9 moles of
O2, what is the maximum number of moles of H2O that could be formed?
3. Consider the following single replacement reaction: 2Al + Fe2O3  Al2O3 + 2Fe. If we had 21 moles of
Al and 30 moles of Fe2O3, what is the maximum number of moles of H2O that could be formed?
4. Consider the following combustion reaction: 2CH3OH + 3O2  2CO2 + 4H2O. What are the maximum
number of moles of CO2 could be formed from 12 moles of O2 and 17 moles of CH3OH?