Mole conversions and stoichiometry worksheet

Chem 1020 Mole conversions and stoichiometry worksheet

1. How many Ag atoms are in 2.43 mol Ag atoms?

2.43 mol Ag atoms ? 6.022?1023 Ag atoms = 1.46?1024 Ag atoms 1 mol Ag atoms

2. How many Br2 molecules are in 18.2 mol Br2 molecules?

18.2

mol

Br2

molecules ?

6.022 ?1023 Br2 molecules 1 mol Br2 molecules

= 1.10?1025

Br2

molecules

3. 7.53 ? 1028 Al atoms is equal to how many mol Al atoms?

7.53?1028

Al

atoms ?

1 mol Al 6.022 ?1023

atoms Al atoms

= 1.25?105

mol

Al

atoms

4. 2.932 ? 1017 H2O molecules is equal to how many mol H2O molecules?

2.932 ?1017

H2O

molecules

?

1 mol H2O 6.022?1023 H

molecules 2O molecules

=

4.869 ?10-7

mol

H2O

molecules

5. How many mol N atoms are in 8.3 mol HCN?

8.3 mol HCN ? 1 mol N atoms = 8.3 mol N atoms 1 mol HCN

6. How many mol H atoms are in 2.63 mol CH2O?

2.63

mol

CH2O ?

2 mol H atoms 1 mol CH2O

=

5.26

mol

H

atoms

7. How many Cl atoms are in 3.63 mol CH2Cl2?

3.63

mol

CH2Cl2

?

2 mol Cl atoms 1 mol CH3Cl2

?

6.022 ?1023 1 mol Cl

Cl atoms atoms

=

4.37 ?1024

Cl

atoms

8. How many O atoms are in 6.229 mol Ca(NO3)2?

6.229

mol

Ca(NO3 )2

? 6 mol O atoms 1 mol Ca(NO3 )2

?

6.022?1023 O atoms 1 mol O atoms

=

2.251? 10 25

O

atoms

9. How many mol FeCl3 are in 15.3 g FeCl3?

Molar mass FeCl3 = 55.85 + 3(35.45) = 162.2 g/mol

15.3

g

FeCl3

?

1 mol FeCl3 162.2 g FeCl3

=

0.0943

mol

FeCl3

10. How many mol Na2CO3 are in 23.5 g Na2CO3?

Molar mass Na2CO3 = 2(22.99) +12.01+ 3(16.00) = 105.99 g/mol

23.5

g

Na

2CO3

?

1 mol 105.99

Na 2CO3 g Na2CO3

=

0.222

g

Na 2 CO3

11. What mass is 3.52 mol NaNO3?

Molar mass NaNO3 = 22.99 +14.01+ 3(16.00) = 85.00 g/mol

3.52

mol

NaNO3

?

85.00 g NaNO3 1 mol NaNO3

=

299

g

NaNO3

12. What mass is 7.326 mol C2H4?

Molar mass C2H4 = 2(12.01) + 4(1.008) = 28.052 g/mol

7.326

mol

C2H4 ?

28.052 g C2H4 1 mol C2H4

=

205.5

g

C2H4

13. How many mol H atoms are in 18.2 g NH3?

Molar mass NH3 = 14.01+ 3(1.008) = 17.034 g/mol

18.2

g

NH3

? 1 mol 17.034

NH3 g NH3

?

3

mol H atoms 1 mol NH3

=

3.21

mol

H

atoms

14. How many mol O atoms are in 3.52 g MnO2?

Molar mass MnO2 = 54.94 + 2(16.00) = 86.94 g/mol

3.52

g

MnO2

?

1 mol MnO2 86.94 g MnO2

?

2 mol O atoms 1 mol MnO2

=

0.0810

mol

O

atoms

15. How many S atoms are in 2.35 g Al2S3?

Molar mass Al2S3 = 2(26.98) + 3(32.06) = 150.14 g/mol

2.35

g

Al2S3

? 1 mol Al2S3 150.14 g Al2S3

?

3 mol S atoms 1 mol Al2S3

?

6.022?1023 S atoms 1 mol S atoms

=

2.83?1022

S

atoms

16. How many F atoms are in 5.52 g C2H2F4?

Molar mass C2H2F4 = 2(12.01) + 2(1.008) + 4(19.00) = 102.036 g/mol

5.52

g

C2

H2

F4

?

1 mol 102.036

C2 H 2 F4 g C2H2

F4

?

4 1

mol mol

F atoms C2 H 2 F4

?

6.022 ?1023 F atoms 1 mol F atoms

= 1.30?1023

F

atoms

17. What mass of O is in 7.56 g H2O2?

Molar mass H2O2 = 2(1.008) + 2(16.00) = 34.016 g/mol Molar mass O = 16.00 g/mol

7.56

g

H2O2

?

1 mol 34.016

H2O2 g H2O2

? 1

2 mol O mol H2O2

? 16.00 g O 1 mol O

=

7.11

g

O

18. What mass of Cl is in 38.2 g PCl3?

Molar mass PCl3 = 30.97 + 3(35.45) = 137.32 g/mol Molar mass Cl = 35.45 g/mol

38.2

g

PCl3

?

1 mol 137.32

PCl3 g PCl3

?

3 mol Cl 1 mol PCl3

?

35.45 g Cl 1 mol Cl

=

29.6

g

Cl

For the following 6 questions, consider the following balanced chemical equation:

N2 + 3H2 2NH3

Molar mass N2 = 2(14.01) = 28.02 g/mol Molar mass H2 = 2(1.008) = 2.016 g/mol Molar mass NH3 = 14.01+ 3(1.008) = 17.034 g/mol

19. How many mol NH3 can be produced from 7.23 mol N2 (assuming H2 is in excess)?

7.23

mol

N2 ?

2 mol NH3 1 mol N2

= 14.5

mol

NH3

20. How many mol H2 must react with 3.26 mol N2?

3.26

mol

N

2

?

3 1

mol mol

H2 N2

= 9.78

mol

H2

21. How many grams of N2 must react if 25.0 g NH3 are formed?

25.0

g

NH

3

?

1 mol 17.034

NH3 g NH3

? 1 mol N2 2 mol NH3

? 28.02 g N2 1 mol N2

=

20.5

g

N2

22. How many grams H2 will react with 15.3 g N2?

15.3

g

N

2

?

1 mol N2 28.02 g N2

? 3 mol H2 1 mol N2

? 2.016 g H2 1 mol H2

= 3.30

g

H2

23. If 2.36 g N2 and 1.52 g H2 react together, what mass NH3 can be produced? Which is the limiting reactant?

2.36

g

N2

?

1 mol N2 28.02 g N2

? 2 mol NH3 ? 17.034 g NH3 1 mol N2 1 mol NH3

=

2.87 g NH3

1.52

g

H2 ?

1 mol H2 2.016 g H2

? 2 mol NH3 3 mol H2

? 17.034 g NH3 1 mol NH3

= 8.56

g

NH3

There is enough N2 to make 2.87 g NH3, and there is enough H2 to make 8.56 g NH3. N2 is the limiting reactant since it produces the smaller product mass. 2.87 g NH3 can be produced (this is the theoretical yield).

24. If 5.32 g N2 and 15.8 g H2 react together, what mass NH3 can be produced? Which is the limiting reactant?

5.32

g

N

2

?

1 mol N2 28.02 g N

2

? 2 mol NH3 1 mol N2

? 17.034 g NH3 1 mol NH3

=

6.47 g NH3

15.8

g

H2

?

1 mol H2 2.016 g H2

?

2 mol NH3 3 mol H2

? 17.034 g NH3 1 mol NH3

= 89.0

g

NH3

There is enough N2 to make 6.47 g NH3 and there is enough H2 to make 89.0 g NH3. N2 is the limiting reactant because it makes the smaller product mass. 6.47 g NH3 can be produced (this is the theoretical yield).

For the following 6 questions, consider the following balanced chemical equation:

2C2H2 + 5O2 4CO2 + 2H2O

Molar mass C2H2 = 2(12.01) + 2(1.008) = 26.036 g/mol Molar mass O2 = 2(16.00) = 32.00 g/mol

Molar mass CO2 = 12.01 + 2(16.00) = 44.01 g/mol Molar mass H2O = 2(1.008) + 16.00 = 18.016 g/mol

25. How many mol of CO2 can be formed if 8.26 mol C2H2 react (assuming excess O2)?

8.26

mol

C2

H2

?

4 2

mol mol

CO2 C2H2

= 16.5

mol CO2

26. How many mol C2H2 will react with 20.3 mol O2?

20.3

mol

O2

?

2 mol C2H2 5 mol O2

= 8.12

mol C2H5

27. How many g of H2O can be formed if 36.2 g C2H2 react (assuming excess O2)?

36.2

g

C2H2

?

1 mol 26.036

C2H2 g C2H2

?

2 mol H2O 2 mol C2H2

? 18.016 1 mol

g H2O H2O

=

25.0

g

H2O

28. How many g O2 will react with 12.2 g C2H2?

12.2

g

C2H

2

?

1 mol 26.036

C2H2 g C2H

2

? 5 mol O2 2 mol C2H2

? 32.00 g O2 1 mol O2

= 37.5

g O2

29. If 2.l3 g C2H2 and 3.63 g O2 react, how many grams CO2 can be formed? Which is the limiting reactant?

2.13

g

C2

H

2

?

1 mol 26.036

C2H2 g C2H

2

? 4 mol CO2 2 mol C2H2

? 44.01 g CO2 1 mol CO2

=

7.20 g

CO2

3.63

g

O2

?

1 mol O2 32.00 g O2

? 4 mol CO2 5 mol O2

? 44.01 g CO2 1 mol CO2

=

3.99 g CO2

There is enough C2H2 to make 7.20 g CO2 and there is enough O2 to make 3.99 g CO2. O2 is the limiting reactant since it produces the smaller product mass. 3.99 g CO2 can be produced (this is the theoretical yield).

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