All calculations
Gas volume at RTP
Quantitative chemistry
AQA 8462
ORIGINAL
Higher tier
gas volume(dm3) = moles x 24
At room temperature and pressure, each mole occupies 24 dm3 or 24 000 cm3.
Verified against AQA 8462 (2026 spec)
Work it, then mark it
Do each calculation on paper first, then reveal the mark scheme and tick the marks you actually earned — the same way you should mark past papers.
Q1
3 marks
Calculate the volume occupied by 0.075 mol of carbon dioxide at RTP. Give the answer in cm3.
Do the calculation on paper first — then mark it.
Where the marks get lost
- Using 24 000 and then converting to cm3 again.
- Applying the 24 dm3 value when conditions are not RTP.
Exam tip: Choose either 24 dm3/mol or 24 000 cm3/mol to match the requested unit.
Calculations are the most trainable marks in chemistry
They come up every paper and reward a clean method. Send me one you keep dropping marks on — your first lesson is free.