# Converting between mass and volume using moles

I can combine mathematical relationships to calculate an unknown mass or volume.

# Converting between mass and volume using moles

I can combine mathematical relationships to calculate an unknown mass or volume.

## Lesson details

### Key learning points

- The volume of one mole of any gas at room temperature and pressure (20℃ and 1 atmosphere pressure) is 24 dm³.
- Reacting mass calculations can use a combination of mass to volume calculations and vice versa.
- Amount of substance (moles) can be calculated using multiple equations.
- The choice of equation for calculating moles depends on the context of the problem or calculation.

### Common misconception

Pupils use an incorrect mathematical relationship to calculate the number of moles in a sample.

Depending on the type of substance (solid, solution or gas) a specific mathematical relationship for moles must be used. Challenge pupils to classify substances as (s), (aq), or (g) and apply correct mathematical relationship.

### Keywords

Mole - A mole of something is 6.02 × 10²³ of it. The mass of a mole of a substance is its relative mass expressed in grams.

Volume - Volume is how much 3D space matter occupies. It is usually measured in cm³.

Molar gas volume - Molar gas volume is the volume occupied by one mole of any gas. It is equal to 24 dm³ or 24 000 cm³ at room temperature and pressure.

Stoichiometry - Stoichiometry refers to the molar ratio of the reactants and products in a chemical reaction.

Balanced symbol equation - A balanced symbol equation describes a reaction using a symbol equation with coefficients, which ensure there are equal numbers of atoms of each element on both sides of the symbol equation.

### Equipment

Sample of limestone (calcium carbonate), balance, tongs, heatproof mat, Bunsen burner, tripod, gauze.

### Content guidance

- Risk assessment required - equipment

### Supervision

Adult supervision required

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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