Pupil sheet · Concentration, gas volumes and yield

Concentration, gas volumes and yield — final check

Name ______________________ Date ____________

Work alone, with the lesson closed. Answer every question; there are no hints.

1. calculate

Supplement. (a) What volume does 0.150 mol of nitrogen take up at r.t.p., in dm³? (b) What volume does 0.0100 mol of chlorine take up at r.t.p., in cm³? Give your answers to 3 significant figures.

(a) Volume of nitrogen: ______________ unit ________

(b) Volume of chlorine: ______________ unit ________

2. calculate

Supplement. Sodium carbonate reacts with excess acid: Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂. What volume of carbon dioxide, in cm³ at r.t.p., does 1.06 g of sodium carbonate give? (Ar: C 12, O 16, Na 23.) Give your answer to 3 significant figures.

Volume of carbon dioxide: ______________ unit ________

3. calculate

Supplement. Aluminium burns: 4Al + 3O₂ → 2Al₂O₃. What mass of aluminium oxide can 5.40 g of aluminium make? (Ar: O 16, Al 27.) Give your answer to 3 significant figures.

Mass of aluminium oxide: ______________ unit ________

4. calculate / deduce

Supplement. 0.650 g of zinc is added to 50.0 cm³ of 0.500 mol/dm³ hydrochloric acid: Zn + 2HCl → ZnCl₂ + H₂. (a) Which reactant is limiting? (b) What volume of hydrogen forms, in cm³ at r.t.p.? (Ar: Zn 65.) Give your answer to 3 significant figures.

(b) Volume of hydrogen: ______________ unit ________

(a) Which reactant is limiting? Show how you decided.

5. calculate

Supplement. Sodium hydroxide reacts with sulfuric acid: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. What volume of 0.100 mol/dm³ sodium hydroxide solution reacts exactly with 0.00250 mol of sulfuric acid? Give your answer in cm³. Give your answer to 3 significant figures.

Volume of sodium hydroxide solution: ______________ unit ________

6. calculate

Supplement. 2.40 g of magnesium burns: 2Mg + O₂ → 2MgO. 3.60 g of magnesium oxide is collected. (a) What is the theoretical yield? (b) What is the percentage yield? (Ar: O 16, Mg 24.) Give your answers to 3 significant figures.

(a) Theoretical yield: ______________ unit ________

(b) Percentage yield: ______________ unit ________

7. calculate

Supplement. (a) What is the percentage by mass of nitrogen in urea, CO(NH₂)₂? (b) A 2.00 g sample of fertiliser contains 1.90 g of urea. What is its percentage purity? (Ar: H 1, C 12, N 14, O 16.) Give your answers to 3 significant figures.

(a) Nitrogen in urea: ______________ unit ________

(b) Percentage purity: ______________ unit ________

8. calculate / deduce

Supplement. Glucose contains 40.0 % carbon, 6.7 % hydrogen and 53.3 % oxygen by mass, and its Mr is 180. (a) What is the mass of one empirical formula? (b) How many empirical-formula units are in one molecule? (c) Write its empirical formula and its molecular formula. (Ar: H 1, C 12, O 16.)

(a) Mass of one empirical formula: ______________ unit ________

(b) Empirical-formula units in one molecule: ______________ unit ________