Quantitative ChemistryDefinitions

Key Definitions

Part of Gas VolumeGCSE Chemistry

This definitions covers Key Definitions within Gas Volume for GCSE Chemistry. Topic 19: Gas Volume It is section 5 of 11 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.

Topic position

Section 5 of 11

Practice

20 questions

Recall

20 flashcards

📖 Key Definitions

Molar gas volume: The volume occupied by one mole of any gas at a specified temperature and pressure. At RTP this is 24 dm³/mol (24,000 cm³/mol).

RTP (Room Temperature and Pressure): The conditions used in GCSE gas calculations — 20°C (293 K) and 1 atmosphere (101 kPa). All gas volumes of 24 dm³/mol apply at these conditions.

dm³: Cubic decimetre — the same as one litre. 1 dm³ = 1000 cm³. Gas volumes are commonly given in either dm³ or cm³; always check which unit is needed.

Volume = moles × 24: The key formula at RTP. Can also be written as moles = volume ÷ 24 (when volume is in dm³).

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Read this section alongside the surrounding pages in Gas Volume. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Gas Volume

What is the molar gas volume at RTP (room temperature and pressure)?

  • A. 12 dm³/mol
  • B. 22.4 dm³/mol
  • C. 24 dm³/mol
  • D. 48 dm³/mol
1 markfoundation

Explain why the molar gas volume of 24 dm³/mol is only valid at RTP.

2 marksstandard

Quick Recall Flashcards

How do you convert cm³ to dm³?
Divide by 1000 1 dm³ = 1000 cm³ Example: 2400 cm³ = 2.4 dm³
What is the molar gas volume at RTP?
24 dm³/mol (or 24,000 cm³/mol) One mole of ANY gas occupies 24 dm³ at room temperature and pressure

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