Gases and Solutions

Question 1

What is the volume occupied by one mole of gas at room temperature and pressure (r.t.p.)?

Answer 1

24 dm³

Room temperature and pressure are defined as 20 ℃ and 1 atm.

Question 2

What is the formula to find the volume of gas in dm³ at r.t.p. given the mass of the gas?

Answer 2

Volume of gas = (Mass of gas (g) / Mr of gas) x 24

Mr is the mass of one mole of a substance.

Question 3

Calculate the volume of 319.5 g of chlorine at r.t.p. if its molar mass is 71 g/mol.

Answer 3

108 dm³

Volume = (319.5 g / 71 g/mol) x 24

Question 4

How can you calculate the volume of gases in reactions?

Answer 4

Use the volume of one gas to find the volume of another based on stoichiometry

Example: 2CO + O₂ → 2CO₂ shows 1 volume of O₂ produces 2 volumes of CO₂.

Question 5

What is concentration in the context of solutions?

Answer 5

The amount of a substance in a certain volume of solution

It can be measured in mass/volume or mol/volume.

Question 6

What happens to the concentration of a solution when more solute is added?

Answer 6

The concentration increases

More solute in a given volume means a more concentrated solution.

Question 7

How do you calculate the concentration of a solution in g/dm³?

Answer 7

Concentration = mass of solute (g) / volume of solvent (dm³)

This formula measures the mass of a substance in a given volume.

Question 8

What is the concentration in g/dm³ of a solution with 30 g of sodium chloride dissolved in 0.2 dm³ of water?

Answer 8

150 g/dm³

Concentration = 30 g / 0.2 dm³.

Question 9

Convert 500 cm³ to dm³.

Answer 9

0.5 dm³

500 cm³ / 1000 = 0.5 dm³.

Question 10

What is the formula for concentration in mol/dm³?

Answer 10

Concentration = number of moles of solute (mol) / volume of solvent (dm³)

This measures the number of moles in a given volume.

Question 11

What is the concentration in mol/dm³ of a solution with 2 moles of salt in 500 cm³?

Answer 11

4 mol/dm³

Convert 500 cm³ to dm³ to use in the formula.