# General A003: Mole calculations

Quiz: Mole calculations involving gases. Note: This quiz uses litres (L) as the unit of volume; this can be treated as equivalent to the dm3used in some UK curricula. Where not otherwise stated presume volume measurements are at STP.

The following questions are multiple choice; mark the answer which you think is the most appropriate. These questions are for self-testing only, and are not suitable for assignments or exams.

1. When 12.0 g carbon burns completely to give carbon dioxide, how many grams of oxygen are consumed?

 A 8.0 g B 12.0 g C 16.0 g D 24.0 g E 32.0 g

2. When 12.0 g carbon burns completely to give carbon dioxide, how many litres (at STP) of oxygen are consumed?

 A 11.2 L B 16.0 L C 22.4 L D 32.0 L E 44.8 L

3. When 24.3 g magnesium burns completely to give magnesium oxide (MgO), how many litres (at STP) of oxygen are consumed?

 A 11.2 L B 16.0 L C 22.4 L D 24.3 L E 32.0 L

4. Hydrogen reacts with chlorine according to the equation:

H2(g) + Cl2(g) → 2 HCl(g)

If 0.05 L of hydrogen gas reacts completely with chlorine gas, how much hydrogen chloride is produced (at STP)?

 A 0.025 L B 0.05 L C 0.10 L D 0.224 L E 0.448 L

5. Propane is used in some rural areas as a domestic heating fuel. It burns in air according to the equation:

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g)

If 20 L propane burns completely in oxygen, what volume (at STP) of carbon dioxide will be produced?

 A 6.67 L B 20 L C 22.4 L D 60 L E 67.2 L

6. What mass of H2O will be produced when 11.2 L butane (C4H10) is burnt in excess oxygen (at STP)?

 A 11.2 g B 18.0 g C 45.0 g D 90.0 g E 180 g

7. A sample of benzene (C6H6) is burnt in excess oxygen, and produces 67.2 L carbon dioxide at STP. What was the mass of benzene in the sample?

 A 11.2 g B 39.0 g C 44.0 g D 78.0 g E 156 g

8. A sample of 13.0 g ethyne (C2H2) is hydrogenated fully over a Pd catalyst to produce ethane (C2H6) in quantitative (100%) yield. What volume (at STP) of hydrogen is consumed in the reaction?

 A 11.2 L B 13.0 L C 22.4 L D 26.0 L E 39.0 L

9. Sulfur dioxide (10.0 L at STP) is oxidized completely by oxygen in the presence of a vanadium pentoxide catalyst to produce sulfur trioxide. The equation for the reaction is: 2 SO2(g) + O2(g) → 2 SO3(g) After reaction, the SO3 is returned to STP. What is the total volume reduction that occurs over the course of the reaction?

 A 5.0 L B 10.0 L C 11.2 L D 12.4 L E 15.0 L

10. A sample of 0.30 L fluorine (at STP) is reacted completely with sulfur to produce sulfur hexafluoride (SF6). What volume of SF6 is produced, after it is returned to STP?

 A 0.025 L B 0.05 L C 0.10 L D 0.30 L E 0.90 L

1. E

2. C

3. A

4. C

5. D

6. C

7. B

8. C

9. A

10. C