Pupil sheet · Concentration, gas volumes and yield
Concentration, gas volumes and yield — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. state / explain
Supplement. (a) What volume does one mole of a gas take up at r.t.p.? (b) One mole of hydrogen has a mass of 2 g and one mole of carbon dioxide 44 g. Explain why they take up the same volume at r.t.p.
(a) Volume of one mole
(b) Why the volumes are the same
2. calculate
Supplement. Iron is made from iron(III) oxide: Fe2O3 + 3CO → 2Fe + 3CO2. What mass of iron can 16.0 g of iron(III) oxide give? (Ar: C 12, O 16, Fe 56.) Give your answer to 3 significant figures.
Mass of iron: ______________ unit ________
3. explain
Supplement. A pupil adds different masses of magnesium to 12.0 cm³ of 0.500 mol/dm³ hydrochloric acid each time and collects the hydrogen. The table shows the results. Explain (a) why the volume rises at first and (b) why it stops rising at 72 cm³.
| Mass of magnesium in g | Volume of hydrogen in cm³ |
|---|---|
| 0.030 | 30 |
| 0.060 | 60 |
| 0.090 | 72 |
| 0.120 | 72 |
(a) Why the volume rises
(b) Why it stops at 72 cm³
4. calculate
Supplement. 10.0 g of calcium carbonate is heated: CaCO3 → CaO + CO2. 5.04 g of calcium oxide is collected. (a) What is the theoretical yield of calcium oxide? (b) What is the percentage yield? (c) What is the percentage by mass of calcium in calcium oxide? (Ar: C 12, O 16, Ca 40.) Give your answers to 3 significant figures.
(a) Theoretical yield: ______________ unit ________
(b) Percentage yield: ______________ unit ________
(c) Calcium in calcium oxide: ______________ unit ________
5. deduce
Supplement. An oxide of sulfur is 40.0 % sulfur by mass. What is its empirical formula? (Ar: O 16, S 32.)
Circle one answer.
- S2O3
- SO
- SO3
- SO2
Show your working.