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Stoichiometry Review

Total questions: 25

Worksheet time: 50mins

Name
Class
Date
1.
Using the following equation:
Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(l)
How many moles of iron can be made from  6 moles H2
a)
4 moles Fe
b)
6 moles Fe
c)
9 moles Fe
d)
2 moles Fe
2.

2 NaClO3 (s) → 2NaCl (s) +3 O2 (g)

How many grams of O2 will be produced from 12.00 moles of NaClO3?

a)

256 g of O2

b)

576 g of O2

c)

288 g O2

d)

32 g O2

3.

2H2 + O2 → 2H2O

How many grams of H2O can be produced from 3.91 g of O2?

a)

1.905

b)

4.4

c)

2.2

d)

1.1

4.

CH4 + 2 O2 → CO2 + 2 H2O

How many moles of carbon dioxide are produced from the combustion of 110 g of CH4?

a)

13.7 mol

b)

2.75 mol

c)

6.11 mol

d)

6.85 mol

5.
What is the measured amount of a product obtained from a chemical reaction?
a)
mole ratio
b)
theoretical yield
c)
percentage yield
d)
actual yield
6.
If a chemist calculates the maximum amount of product that could be obtained in a chemical reaction, he or she is calculating the
a)
theoretical yield
b)
mole ratio
c)
actual yield
d)
percentage yield
7.
Mole ratios are obtained from the
a)
balanced chemical equation
b)
periodic table
c)
molar mass
8.
When does a chemical reaction stop?
a)
When the lab is finished
b)
When the excess reactant is used up
c)
When the limiting reactant is used up
d)
Chemical reactions never stop
9.
Using the following equation:
Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(l)
How many moles of iron can be made from  6 moles H2
a)
4 moles Fe
b)
6 moles Fe
c)
9 moles Fe
d)
2 moles Fe
10.
N2 +  3H2 → 2NH3 
How many moles of hydrogen are needed to react with 2 moles of nitrogen?
a)
6
b)
2
c)
3
d)
1
11.

In the image, which reactant is limiting?

a)

The white molecules, because there are extra.

b)

The black atoms, because they are completely used up.

c)

The white molecules, because they are completely used up.

d)

The black atoms, because there are extra.

12.

How many moles of water are in this equation?

a)

0

b)

1

c)

2

d)

can't be determined

13.

Mole Ratios used for conversions are derived from:

a)

the molar mass of the reactants in the balanced chemical equation

b)

the coefficients of the balanced chemical equation

c)

the subscripts of the products in the balanced chemical equation

d)

the group number of each element in the balanced chemical equation

14.

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

Ethane (C2H6) combusts in the above reaction. What is the mole ratio of ethane to oxygen gas?

a)
b)
c)
d)
15.

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

Ethane (C2H6) combusts in the above reaction. What is the mole ratio of carbon dioxide to water?

a)
b)
c)
d)
16.
The ______________ yield is the maximum amount of product possible in a reaction. This determines the amount of product that should be produced in a perfect setting
a)
Percent
b)
actual
c)
stoichiometry
d)
theoretical
17.

When reacting Na with Cl2, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?

a)

90.4%

b)

104%

c)

96.15%

d)

1.04%

18.
Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.
a)
1.16%
b)
116%
c)
85%
d)
76%
19.

Competing reactions might occur forming other products causing your actual yield to be less than your theoretical yield.

a)

true

b)

false

20.

What is the equation to calculate percent yield?

a)

(Actual yield / Theoretical yield) x 100% = Percent yield

b)

(Theoretical yield / Actual yield) x 100% = Percent yield

c)

Mass (1 Mole / Molar mass) x 100% = Percent yield

d)

Mass x Speed x 100% = Percent yield

21.

What does percent yield indicate?

a)

The mass of product that should be obtained

b)

How quickly the reaction is completed

c)

The product of product actually obtained

d)

The efficiency of the chemical reaction

22.

Given a balanced equation involving A and B, which set of conversions must you make to change mass A to mass B?

a)

mass A --> moles A --> moles B --> mass B

b)

moles A --> mass A --> mass B

c)

moles B --> mass A --> mole A --> mass B

d)

moles A --> moles B --> mass B

23.

What is an excess reactant?

a)

The substance that creates a surplus of the reactant after the reaction is complete

b)

The reactant that doesn't get used up as a reactant and is left over

c)

The reactant that is used up first and prevents more from being made

d)

This is another term for a limiting reactant

24.

Say you take a reactant A and calculate the amount of moles of another reactant B required to use up all of A. How do you know which of two reactants is the limiting one?

a)

If the calculated value of B is larger than the amount of A, then B is the limiting reactant.

b)

You compare the calculated amount of B to the actual amount available. If more is required, then A is the limiting reactant. If less is required, then B is the limiting reactant.

c)

If the calculated value of B is larger than the amount of A, then A is the limiting reactant.

d)

You compare the calculated amount of B to the actual amount available. If more is required, then B is the limiting reactant. If less is required, then A is the limiting reactant.

25.

What is a limiting reactant?

a)

The substance that is in excess that doesn't get used up as a reactant.

b)

The reactant that is used up first and prevents more product from being made.

c)

The reactant that makes the product.

d)

The reactant that is used up last and prevents more product from being made.