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Unit 4 Stoichiometry Review 2021

Total questions: 20

Worksheet time: 2hrs 40mins

Name
Class
Date
1.

Read the example of the stoichiometry problems below and respond the the question below it.
3X + 2Y ---> 5Z 


If you react 300 grams of compound X with excess amounts of compound Y, how many grams of compound Z will be produced? 
What information or calculations will you need complete before you set up this problem to solve it? 
Select ALL answers that apply. 

a)

the molar mass of compound X 

b)

the molar mass of compound Y 

c)

the molar mass of compound Z 

d)

the mole ratio of compound Y to compound Z in the balanced equation 

e)

the mole ratio of compound X to compound Z in the balanced equation 

2.

What is the first thing you must do to solve a stoichiometry problem?

a)

Make sure the chemical reaction is Balanced

b)

Panic

c)

Make sure the Equation is Unbalanced

d)

Multiple by Avogadro's Number

3.

___KNO3 → ___KNO2 + ___O2

What coefficients are needed to balance the reaction?

a)

2, 2, 1

b)

2, 3, 2

c)

1, 2, 2

d)

1, 3, 1

4.

What is the molar mass of KNO3? Round your answer to one decimal place

(a)  

5.

_?__KNO3 → ?KNO2 + __?_O2
What mole ratio between KNO3 and O2 in the balanced chemical equation?

a)


 1 mole O22 moles KNO3\frac{1\ mole\ O_2}{2\ moles\ KNO_3}  

b)

 2 moles O21 mole KNO3\frac{2\ moles\ O_2}{1\ mole\ KNO_3}  

c)

 1 mole O 2 moles KNO2\frac{1\ mole\ O\ }{2\ moles\ KNO_2}  

d)

 2 moles O2 moles KNO3\frac{2\ moles\ O}{2\ moles\ KNO_3}  

6.

What is the molar mass of oxygen, O2?

Round your answer to the nearest whole number.

(a)  

7.

The UNBALANCED chemical reaction is below. You balanced this in a previous problem ,use those values to solve the following.

?_KNO3 → _?__KNO2 + ___O2

How many grams of oxygen will be formed when 505.5 grams of KNO3 are decomposed?

Round your answer to 1 decimal place

(a)  

8.

What is the molar mass of NaClO3?

Round the atomic masses to 1 decimal place before you sum them.

(a)  

9.

2 NaClO3 (s) → 2NaCl (s) +3 O2 (g)

What is the molar ratio of NaClO3 and O2?

a)

2 moles NaClO31 moles O2\frac{2\ \ moles\ NaClO_3}{1\ moles\ O_2}

b)

3 moles NaClO32 moles O2\frac{3\ moles\ NaClO_3}{2\ moles\ O_2}

c)

3 moles O22 moles NaClO3\frac{3\ moles\ O_2}{2\ moles\ NaClO_3}

d)

2 moles O22 moles NaClO3\frac{2\ moles\ O_2}{2\ moles\ NaClO_3}

10.

2 NaClO3 (s) → 2NaCl (s) +3 O2 (g)

How many grams of O2 will be produced from 1278 grams of NaClO3?

a)

256 g of O2

b)

576 g of O2

c)

288 g O2

d)

32 g O2

11.

2Na + 2H2O → 2NaOH+ H2


How many grams of hydrogen are produced if 120 g of Na are available?

a)

5.27 g

b)

2.6 g

c)

690 g

d)

45 g

12.

In the equation 2Al2O3 → 4Al + 3O2, what is the mole ratio of aluminum to oxygen?

a)

10:6

b)

3:4

c)

4:3

d)

2:3

13.

2Al + 3H2SO4 → Al2(SO4)3 + 3H2

How many grams of aluminum sulfate would be formed if 250g H2SO4 completely reacted with aluminum?

a)

0.85 g

b)

290 g

c)

450 g

d)

870 g

14.

What is the mole ratio of H2O to H3PO4 in the following chemical equation? P4O10 + 6 H2O → 4 H3PO4

a)

6:4

b)

4:6

c)

1:3

d)

3:1

15.
Balance this equation
_Zn+_HCl-->_ZnCl2 +_H2
a)
1,1,2,1
b)
1,1,1,2
c)
1,2,1,1
d)
2,1,1,1
16.

N2 + 3H2 → 2NH3

What is the mole ratio between N2 and NH3 in the above reaction?

a)

1 moles NH3 / 2 moles N2

b)

2 moles NH3 / 1 moles N2

c)

2 moles N2 / 3 moles NH3

d)

1 moles N2 / 3 moles NH3

17.

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)
18.

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

New problem: If 16 moles of carbon dioxide are formed by this reaction, how many moles of water were also produced?

a)

4 mol H2O

b)

6 mol H2O

c)

24 mol H2O

d)

96 mol H2O

19.

Read the problem below and then answer the question at the bottom.

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

If 195 grams of ethane C2H6 are combusted with excess amounts of O2, how many grams of CO2 were produced?


What information or calculations will you need to solve this problem?

Select ALL answers that apply.

a)

The mole ratio of C2H6 to O2 in the reaction

b)

The mole ratio of C2H6 to CO2 in the reaction

c)

the molar mass of CO2

d)

The molar mass of oxygen O2

e)

The molar mass of ethane C2H6

20.

2 C2H6 + 7 O2 → 4 CO2 + 6 H2O

If 195 grams of ethane C2H6 combusted with excess amounts of oxygen, how many grams of CO2 were produced?

a)

286 grams of CO2

b)

572 grams of CO2

c)

1144 grams of CO2

d)

143 mol H2O