The Mole and Stoichiometry Test Version 2
Do Not Write on this Test
Multiple Choice (2 points each)
_______ 1) The sum of the atomic masses of all the atoms in a compound is called
A.
Molar mass.
B.
Empirical mass.
C.
Molar volume.
D.
Percentage composition.
_______ 2)
A mole of carbon contains 6.02 X 1023
A.
Atoms.
B.
Formula units.
C.
Molecules.
D.
Grams.
_______ 3)
The molar mass of a compound depends upon the
A.
Number of molecules in one mole.
B.
Mass of each element in the compound.
C.
Properties of the compound.
D.
Empirical formula of a compound.
_______ 4)
It is possible to convert moles to particles by
A.
Multiplying by 6.02 X 1023.
B.
Dividing by 6.02 X 1023.
C.
Multiplying by the molar mass.
D.
Dividing by the molar mass.
_______ 5)
What is percentage composition of carbon in heptane (C7H16)?
A.
12 %
B.
19%
C.
68 %
D.
84 %
________6)
What is true about the molar mass of chlorine gas?
A. The molar mass is 35.5 g/mol
B. The molar mass is 71.0 g/mol
C. The molar mass is 6.02 x1023
D. None of the above
_______7)
How many atoms are in 3.5 mol of arsenic atoms
A) 5.8 x 10-24 atoms B) 7.5 x 1023 atoms
C) 2.1 x 1024 atoms D) 1.26 X1024 atoms
_______8)
What is the molar mass of AuCl2 ?
A) 96 g/mol
B) 232 g/mol
C) 130 g/mol
D) 267.8 g/mol
_______9)
What is the mass in grams of 7.5 mol of C8H18 ?
A) 0.0512g
B) 15.2g
C) 114g
D) 855g
_______10)
How many atoms of Hydrogen are in 12 grams of CH4 ?
A) 2.89 x1024 atoms
B) 1.806 x1024 atoms
C) 0.625 atoms
D) 3.76 x10 23 atoms
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The Mole and Stoichiometry Test Version 2
Do Not Write on this Test
________11) One of the properties associated with hydrates is:
A. water is loosely attached;
B water is tightly attached;
C ammonia is attached to a molecule of salt;
D. The salt is in water
_______12)
In the reaction 2 Al2O3  4Al + 3O2, what is the mole ratio of Al2O3 to O2
A) 10:6
B) 3:4
C) 2:3
D) 4:3
________13) How many moles of methane (CH4) are required to produce 3 mol of
copper by the reaction _Cu2O + _CH4  _H2O + _Cu + CO2? (Hint: balance the
equation)
A) 0.75 mols;
B) 1.0 mols;
C) 1.5 mols;
D) 0.375 mols;
E). 0.125 mols
________14) 46 g of calcium hydroxide reacts with excess sodium sulfate in aqueous
solution to produce solid calcium sulfate and aqueous sodium hydroxide. How many
moles of calcium sulfate formula units are made? (Hint: determine and balance the
chemical equation)
A) 1.73mol
C) 0.266 mol
B) 0.216 mol
D) 0.432 mol
E. 0.622 mol
For questions 15-17 Hydrogen and nitrogen react to form ammonia according to the
reaction, 3 H2 + N2 2 NH3. If you have 2.0 grams of H2 and 4.0 grams of N2
_______15)
What is the limiting reagent?
A) H2
C) N2
B) NH3
D). More than one is the limiting reactant.
________16) How many grams of NH3 would be produced? (Hint: Use the known
amount of the limiting reagent)
A) 9.33 grams
C) 2.43 grams
_______17)
A) N2
_______18)
B) 0.857 grams
D) 4.67 grams E. None of these are correct.
Which reactant is the excess reagent?
B) NH3
How many grams of the excess reagent is left over?
A) 1.2 grams N2
C) 1.58 grams H2
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C) H2
B) 1.41 grams of H2
D) 9.33 grams N2
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