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4.1.9 Group 1

Paper 1 · Higher combined

What you need to know

  • mass will remain the same if the mass of the gas is
  • Whenever a measurement is made, there is always
  • included in the reaction calculation.
  • some degree of uncertainty about the result.
  • Neither A r or Mr values have any units.
  • scientific data.
  • Uncertainty can be measured by considering the
  • The law of conservation of mass states that during

KO match: The Mr of H₂SO₄ = (1 × 2) + 32 + (16 × 4) = 98

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Self-assessment (checklist)

  • (Add checklist points)

Key steps (method)

  • Identify what the question is testing (definition / calculation / explanation).
  • Use the correct chemistry vocabulary and link cause → effect.
  • If it’s a calculation: write the equation/formula first, then substitute carefully.

Common mistakes

  • Giving a fact without linking it to the question.
  • Missing units / state symbols when asked.
  • Not showing enough working to score method marks.

Exam-style questions (quick)

  1. Define the key term(s) for this mini-topic.
  2. Explain a typical property/result using particle/bonding ideas.
  3. Do a short calculation or interpretation step relevant to this mini-topic.