Lesson 4.3.1.1

4.3.1.1 Conservation of mass and balanced chemical equations Quiz: AQA Chemistry, Unit 3

20 questions

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Lesson 4.3.1.1, Conservation of mass and balanced chemical equations: 20 multiple choice questions for the AQA GCSE Chemistry (8462), Unit 3: Quantitative chemistry, written with Revision Ninja.

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The 20 questions

  1. What does the law of conservation of mass state about atoms?

    • No atoms lost
    • Atoms are doubled
    • Atoms are created
    • Atoms are destroyed
  2. In any closed chemical reaction, how do total masses compare?

    • Products equal reactants
    • Products exceed reactants
    • Reactants exceed products
    • Mass becomes zero
  3. What must be equal on both sides of a balanced symbol equation?

    • Volume of gases
    • Total mass of reactants
    • Number of molecules
    • Number of each atom
  4. Where is a multiplier placed in a chemical equation?

    • Before formula
    • As subscript
    • Above arrow
    • After formula
  5. What does a subscript indicate within a chemical formula?

    • Total mass
    • Number of atoms
    • State of matter
    • Charge of ion
  6. Balance this equation: H2 + O2 -> H2O.

    • 2H2 + O2 -> 2H2O
    • 2H2 + 2O2 -> H2O
    • H2 + 2O2 -> H2O
    • H2 + O2 -> H2O
  7. Balance this equation: Mg + HCl -> MgCl2 + H2.

    • 2Mg + HCl -> MgCl2 + H2
    • Mg + 2HCl -> MgCl + H2
    • Mg + HCl -> MgCl2 + H2
    • Mg + 2HCl -> MgCl2 + H2
  8. When carbon burns in oxygen, how do the total masses compare?

    • Mass products are greater
    • Total mass always decreases
    • Mass products equal reactants
    • Mass products are smaller
  9. In 2CO + O2 -> 2CO2, how many oxygen atoms are on the left side?

    • 6
    • 2
    • 4
    • 3
  10. Which balanced equation fits C2H6 + O2 -> CO2 + H2O?

    • 2C2H6 + 6O2 -> 4CO2 + 6H2O
    • C2H6 + O2 -> CO2 + H2O
    • 2C2H6 + 7O2 -> 4CO2 + 6H2O
    • C2H6 + 3O2 -> 2CO2 + 3H2O
  11. Which equation is balanced?

    • 2Na + 2H2O -> 2NaOH + H2
    • Na + 2H2O -> NaOH + H2
    • Na + H2O -> NaOH + H2
    • 2Na + H2O -> 2NaOH + H2
  12. In C6H12O6 + 6O2 -> 6CO2 + 6H2O, how many carbon atoms are in the products?

    • 1
    • 18
    • 6
    • 12
  13. What do symbol equations use to represent chemical reactions?

    • Physical states only
    • Chemical formulae
    • Energy levels
    • Word descriptions
  14. What does a front multiplier in a chemical equation apply to?

    • Product mass only
    • Only first element
    • Only the subscript
    • Every atom
  15. Which balanced equation shows iron burning in oxygen to form iron(III) oxide?

    • 2Fe + O2 -> Fe2O3
    • Fe + O2 -> Fe2O3
    • 2Fe + 3O2 -> Fe2O3
    • 4Fe + 3O2 -> 2Fe2O3
  16. In the thermal decomposition equation CaCO3 -> CaO + CO2, what is its status?

    • Already balanced
    • Needs a 3 before CO2
    • Needs a 2 before CaCO3
    • Needs a 2 before CaO
  17. Which law is the basis for balancing equations?

    • Conservation of energy
    • Conservation of charge
    • Conservation of volume
    • Conservation of mass
  18. Why must subscripts never be altered when balancing equations?

    • Changes the substance
    • Violates atomic mass
    • Changes equation colour
    • Alters reaction temperature
  19. Which equation is balanced for aluminium burning in oxygen?

    • 4Al + 3O2 -> 2Al2O3
    • 2Al + 3O2 -> Al2O3
    • 2Al + O2 -> Al2O3
    • Al + O2 -> Al2O3
  20. How many atoms are in 2H2O?

    • 2
    • 3
    • 6
    • 4

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