Calculations Involving Masses

Calculations Involving Masses Quiz

Spec 1.43–53 · Edexcel GCSE Chemistry: Quiz

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5 questions, one answer each

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  1. 1. What is the relative formula mass of CO2 (Ar: C=12, O=16)?

    • A. 28
    • B. 44
    • C. 32
    • D. 16

  2. 2. What does an empirical formula show?

    • A. The exact number of atoms in a molecule
    • B. The simplest whole-number ratio of atoms
    • C. The mass of the compound
    • D. The number of moles present

  3. 3. In an open-flask reaction where a gas is released, what happens to the measured mass?

    • A. It increases
    • B. It stays exactly the same
    • C. It appears to decrease, but total mass is conserved
    • D. Mass is genuinely destroyed

  4. 4. A compound has empirical formula CH2 (mass 14) and relative molecular mass 42. What is its molecular formula?

    • A. CH2
    • B. C2H4
    • C. C3H6
    • D. C4H8

  5. 5. 20 g of a solute is dissolved to make 0.5 dm3 of solution. What is its concentration in g dm-3?

    • A. 10
    • B. 20
    • C. 40
    • D. 100

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