Pupil sheet · The mole
The mole — final check
Name ______________________ Date ____________
Work alone, with the lesson closed. Answer every question; there are no hints.
1. state / explain
Supplement. (a) State what is meant by one mole of a substance. (b) 32 g of oxygen, O2, and 23 g of sodium, Na, contain the same number of particles. Explain why. (Ar: O 16, Na 23.)
(a) One mole
(b) Why the numbers are the same
2. calculate
Supplement. (a) Calculate the amount of potassium carbonate, K2CO3, in 13.8 g. (b) A sample of carbon dioxide, CO2, contains 1.505 × 10²² molecules. Calculate its mass. Give each calculated answer to three significant figures. (Avogadro constant: 6.02 × 10²³ per mol.) (Ar: C 12, O 16, K 39.)
(a) Amount of potassium carbonate: ______________ unit ________
(b) Mass of carbon dioxide: ______________ unit ________
3. calculate / deduce / identify
Supplement. A gas jar holds 1.204 × 10²² molecules of a gas. The gas has a mass of 1.28 g. (a) Calculate the amount of gas. (b) Calculate its molar mass. (c) Deduce its relative molecular mass. (d) The gas is one of CO2, H2S, SO2 or Cl2. Identify it. Give each calculated answer to three significant figures. (Avogadro constant: 6.02 × 10²³ per mol.) (Ar: H 1, C 12, O 16, S 32, Cl 35.5.)
(a) Amount of gas: ______________ unit ________
(b) Molar mass: ______________ unit ________
(c) Relative molecular mass: ______________ unit ________
(d) The gas
4. calculate
Supplement. A bottle of potassium sulfate solution, K2SO4, for a plant-feed test is labelled 32.0 g/dm³. (a) Calculate the mass of potassium sulfate in 65.0 cm³ of the solution. (b) Calculate the volume of the solution, in cm³, that contains 4.00 g of potassium sulfate. Give each calculated answer to three significant figures.
(a) Mass of potassium sulfate: ______________ unit ________
(b) Volume in cm³: ______________ unit ________
5. calculate
Supplement. (a) A solution contains 0.0105 mol of solute in 75.0 cm³. Calculate its concentration in mol/dm³. (b) Calculate the volume, in cm³, of 0.600 mol/dm³ solution that contains 0.0180 mol of solute. Give each calculated answer to three significant figures.
(a) Concentration: ______________ unit ________
(b) Volume: ______________ unit ________
6. state
A bottle label reads “Potassium nitrate solution, 20.2 g/dm³”. (a) State what 20.2 g/dm³ tells you about the solution. (b) State the other unit in which a concentration can be measured.
(a) What 20.2 g/dm³ tells you
(b) The other unit