Stoichiometry: Problem Sheet 2

KEY

Chemistry: Stoichiometry ? Problem Sheet 2

Directions: Solve each of the following problems. Show your work, including proper units, to earn full credit.

1.

___ CaCl2 + ___ AgNO3 ___ Ca(NO3)2 + ___ AgCl

How many grams of silver chloride are produced when 45 g of calcium chloride react with excess silver nitrate?

x g AgCl

45 g CaCl 2

1mol CaCl 2 111 g CaCl 2

2 mol AgCl 1 mol CaCl 2

143.5 g AgCl 1mol AgCl

116 g AgCl

2.

___ CuO + ___ H2 ___ Cu + ___ H2O

At STP, how many liters of hydrogen are needed to react with 88 g of copper (II) oxide?

x L H2

88 g CuO 1mol CuO 79.5 g CuO

1mol H2 1mol CuO

22.4 L H2 1mol H2

24.8 L H2

3.

___ Na + ___ H2O ___ NaOH + ___ H2

If 3 liters of hydrogen (at STP) are produced in the above reaction, what mass of sodium was used?

x g Na

3 L H2

1mol H2 22.4 L H2

2 mol Na 23 g Na 1mol H2 1mol Na

6.2 g Na

4.

___ CH4 + ___ O2 ___ CO2 + ___ H2O

What volume of methane is needed to completely react with 500 liters of oxygen?

x L CH4

500 L O 2

1mol O2 22.4 L O2

1mol CH4 22.4 L CH4 2 mol O2 1mol CH4

250 L CH 4

5.

___ CS2 + ___ O2 ___ CO2 + ___ SO2

How many molecules of carbon disulfide will react with 4.21 x 1019 molecules of oxygen?

x molecules C2S

4.21x1019 molecules O2

1mol O2 6.02x1023 molecules O2

1mol CS2 6.02x1023 molecules CS2

3 mol O2

1mol CS2

1.40x1019 molecules CS2

6.

___ C2H6 ___ C2H4 + ___ H2

If 5.76 x 1028 molecules of ethane are broken down, what volume of hydrogen gas is produces at STP?

x L H2

5.76x1028 molecules C2H6

1mol C2H6 6.02x1023 molecules C2H6

1mol H2 1mol C2H6

22.4 L H2 1mol H2

2.14x106 L H2

7.

___ Fe + ___ H2O ___ Fe3O4 + ___ H2

If 67.8 dm3 of hydrogen are produced at STP, how many atoms of iron were used in the reaction?

x atoms Fe

67.8 dm3 H2

1mol H2 22.4 dm3 H2

3 mol Fe 6.02x10 23 atoms Fe

4 mol H2

1mol Fe

1.37x10 24 atoms Fe

8.

___ KClO3 ___ KCl + ___ O2

If 8.65 x 1025 molecules of potassium chloride are produced, what mass of oxygen is produced?

x g O2

8.65 1025 molecules KCl

1mol KCl

6.02 1023 molecules KCl

3 mol O2 32 g O2 2 mol KCl 1mol O2

6897 g O2

9.

___ NaI + ___ Cl2 ___ NaCl + ___ I2

How many molecules of iodine are liberated if 546 g of chlorine react with excess sodium iodide?

x molecules I2

546 g Cl 2

1mol Cl2 71g Cl2

1mol I2 1 mol Cl2

6.02 x 1023 molecules I2 1mol I2

4.63 x 1024 molecules I2

10. ___ Cu + ___ AgNO3 ___ Cu(NO3)2 + ___ Ag

How many grams of silver will be produced if 86 g of copper are used? x g Ag 86 g CuO 1mol Cu 1mol Ag 108 g Ag 292 g Ag 63.5 g Cu 1mol Cu 1mol Ag

11. ___ (NH4)2SO4 + ___ Ca(OH)2 ___ CaSO4 + ___ NH3 + ___ H2O At STP, how many dm3 of ammonia are produced by using 26.0 g of calcium hydroxide?

x L NH3

26.0 g Ca(OH) 2

1mol Ca(OH) 2 74 g Ca(OH) 2

2 mol NH3 1mol Ca(OH) 2

22.4 dm3 NH3 1mol NH3

15.7 dm3 NH3

12. ___ NaCl + ___ H2SO4 ___ HCl + ___ Na2SO4

If 359 g of sodium chloride are consumed in the reaction, how many molecules of sodium sulfate are

produced?

x molecules Na2SO4

395 g NaCl 1mol NaCl 58.5 g NaCl

1mol Na2SO4 2 mol NaCl

6.02 x 1023 molecules Na2SO4 1mol Na2SO4

1.85 x 1023 molecules Na2SO4

13. ___ AgCH3COO + ___ Na3PO4 ___ Ag3PO4 + ___ NaCH3COO What mass of AgCH3COO will react with 4.77 x 1026 molecules of sodium phosphate?

x g AgCH3COO

4.77x10 26 molecules Na3PO4

1mol Na3PO4 6.02x10 23 molecules Na3PO4

14. ___ HgO ___ Hg + ___ O2

3 mol AgCH3COO 167 g AgCH3COO 1mol Na3PO4 1mol AgCH3COO

3.97 x 105 g AgCH3COO

What mass of mercury (II) oxide is required to produce 812 liters of oxygen (at STP)?

x g HgO

812 L O2

1mol O2 22.4 L O2

2 mol HgO 1mol O2

216.6 g HgO 1mol HgO

1.57 x 104 g HgO

15. ___ Ag2O ___ Ag + ___ O2

How many molecules of silver oxide are needed to produce 445 dm3 of oxygen (at STP)?

x molecules Ag2O

445 dm3 O2

1mol O2 22.4 dm3 O2

2 mol Ag2O 6.02x10 23 molecules Ag2O

1mol O2

1mol Ag2O

2.39x10 25 molecules Ag2O

16. ___ Al + ___ HCl ___ AlCl3 + ___ H2

How many liters of hydrogen (at STP) are produced by reacting 3.54 x 1024 atoms of aluminum with excess hydrochloric acid?

x L H2

3.54

1024 atoms Al

6.02

1mol Al 1023 atoms Al

3 mol H2 22.4 L H2 2 mol Al 1mol H2

198 L H2

Answers:

1. 116 g AgCl 2. 24.8 L H2 3. 6.2 g Na 4. 250 L CH4

5. 1.40 x 1019 molecules CS2 9. 4.63 x 1024 molecules I2

6. 2.14 x 106 L H2

10. 292 g Ag

7. 1.37 x 1024 atoms Fe

11. 15.7 dm3 NH3

8. 6897 g O2

12. 1.85 x 1024 molecules

13. 3.97 x 105 g AgCH3COO 14. 1.57 x 104 g HgO 15. 2.39 x 1025 molecules Ag2O 16. 198 L H2

Chemistry: Stoichiometry ? Problem Sheet 2

KEY

1) x g AgCl

45 g CaCl 2

1mol CaCl 2 111 g CaCl 2

2 mol AgCl 1 mol CaCl 2

143.5 g AgCl 1mol AgCl

116 g AgCl

2) x L H2

88 g CuO 1mol CuO 79.5 g CuO

1mol H2 1mol CuO

22.4 L H2 1mol H2

24.8 L H2

3) x g Na

3 L H2

1mol H2 22.4 L H2

2 mol Na 23 g Na 1mol H2 1mol Na

6.2 g Na

4) x L CH4

500 L O 2

1mol O2 22.4 L O2

1mol CH4 22.4 L CH4 2 mol O2 1mol CH4

250 L CH 4

5)

x molecules C2S

4.21x1019 molecules O2

1mol O2 6.02x1023 molecules O2

1mol CS2 6.02x1023 molecules CS2

3 mol O2

1mol CS2

1.40x1019 m

6) x L H2

5.76x1028 molecules C2H6

1mol C2H6 6.02x1023 molecules C2H6

1mol H2 1mol C2H6

22.4 L H2 1mol H2

2.14x106 L H2

7) x atoms Fe

67.8 dm3 H2

1mol H2 22.4 dm3 H2

3 mol Fe 6.02x10 23 atoms Fe

4 mol H2

1mol Fe

1.37x10 24 atoms Fe

8) x g O2

8.65

1025 molecules KCl

6.02

1mol KCl 1023 molecules KCl

3 mol O2 32 g O2 2 mol KCl 1mol O2

6897 g O2

Chemistry: Stoichiometry ? Problem Sheet 2

KEY

9) x molecules I2

546 g Cl 2

1mol Cl2 71g Cl2

1mol I2 1 mol Cl2

6.02 x 1023 molecules I2 1mol I2

4.63 x 1024 molecules I2

10) x g Ag 86 g CuO 1mol Cu 1mol Ag 108 g Ag 292 g Ag

63.5 g Cu 1mol Cu 1mol Ag

11) x L NH3

26.0 g Ca(OH) 2

1mol Ca(OH) 2 74 g Ca(OH) 2

2 mol NH3 1mol Ca(OH) 2

22.4 dm3 NH3 1mol NH3

15.7 dm3 NH3

12)

x molecules Na2SO4

395 g NaCl 1mol NaCl 58.5 g NaCl

1mol Na2SO4 2 mol NaCl

6.02 x 1023 molecules Na2SO4 1mol Na2SO4

1.85 x 1023 molecules

13)

x g AgCH3COO

4.77x10 26 molecules Na3PO4

1mol Na3PO4 6.02x10 23 molecules Na3PO4

3 mol AgCH3COO 167 g AgCH3COO 1mol Na3PO4 1mol AgCH3COO

14) x g HgO

812 L O2

1mol O2 22.4 L O2

2 mol HgO 1mol O2

216.6 g HgO 1mol HgO

1.57 x 104 g HgO

15)

x molecules Ag2O

445 dm3 O2

1mol O2 22.4 dm3 O2

2 mol Ag2O 6.02x10 23 molecules Ag2O

1mol O2

1mol Ag2O

2.39x10 25 molecules Ag2O

16) x L H2

3.54 1024 atoms Al

1mol Al

6.02 1023 atoms Al

3 mol H2 22.4 L H2 2 mol Al 1mol H2

198 L H2

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