Lesson T4.1.2

T4.1.2 Word and symbol equations Quiz: KS3 Chemistry, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T4.1.2, Word and symbol equations: 20 multiple choice questions for the KS3 Chemistry (National Curriculum), Unit 4: Chemical reactions, written with Revision Ninja.

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The 20 questions

  1. What does the arrow mean in a word equation?

    • It means 'reacts to form'
    • It means 'is dissolved in'
    • It means 'is equal to'
    • It means 'is heated to'

  2. In the word equation magnesium + oxygen -> magnesium oxide, which is the product?

    • Magnesium and oxygen
    • Magnesium oxide
    • Oxygen
    • Magnesium

  3. In the word equation hydrogen + oxygen -> water, what are the reactants?

    • Water only
    • Water and oxygen
    • Hydrogen and oxygen
    • Hydrogen only

  4. Which symbol equation is correct for hydrogen gas and oxygen gas reacting to form water?

    • H2 + O -> H2O
    • H2 + O2 -> H2O
    • 2H2 + O2 -> 2H2O
    • 2H + 2O -> H2O2

  5. Why is the equation 2H2 + O2 -> 2H2O balanced?

    • There are four hydrogen atoms and two oxygen atoms on both sides
    • There are three oxygen atoms on the left only
    • It contains only one product
    • There are two hydrogen atoms on the left and four on the right

  6. In the symbol equation 2Mg + O2 -> 2MgO, how many magnesium atoms are on the right?

    • Three
    • One
    • Two
    • Four

  7. What is the state symbol for a gas?

    • (l)
    • (g)
    • (aq)
    • (s)

  8. What state symbol shows a solid?

    • (l)
    • (g)
    • (aq)
    • (s)

  9. Write the word equation for iron reacting with sulfur to make iron sulfide.

    • Sulfur + iron sulfide -> iron
    • Iron + sulfur -> iron sulfide
    • Iron sulfide -> iron + sulfur
    • Iron + sulfide -> sulfur

  10. Which symbol equation shows a balanced reaction of carbon and oxygen to make carbon dioxide?

    • C + O2 -> CO2
    • C + O -> CO2
    • C + 2O -> C2O2
    • C2 + O2 -> CO2

  11. Which is the correct form for a word equation?

    • Symbols only, with no names, and an arrow pointing to the products
    • Reactants on the left, products on the right, with a + between names
    • Products on the left, reactants on the right, with an arrow between the names
    • Reactants and products listed in no fixed order, separated by commas

  12. In a symbol equation, what does a number in front of a formula show?

    • The mass of the substance in grams
    • The temperature at which the reaction happens
    • The number of protons in the atom
    • How many of that formula are needed or made

  13. What does a small number written after a symbol, like the 2 in O2, show?

    • How many atoms of that element are joined in one molecule
    • The charge on the element when it forms an ion in a solution
    • How many molecules of that element are present in the reaction mixture
    • The state of the element at room temperature and normal pressure

  14. A student wrote 2H2 + O2 -> H2O. Which correction makes it balanced?

    • H2 + O2 -> 2H2O
    • 2H2 + O2 -> 2H2O
    • 2H2 + 2O2 -> H2O
    • H2 + O -> H2O

  15. Which is the correct word equation for copper carbonate decomposing into copper oxide and carbon dioxide?

    • Copper carbonate -> copper oxide + carbon dioxide
    • Copper + carbon dioxide -> copper carbonate
    • Copper oxide + carbon dioxide -> copper carbonate
    • Copper carbonate + carbon dioxide -> copper oxide

  16. Which set of coefficients balances N2 + H2 -> NH3, in the order N2, H2, NH3?

    • 1, 2, 3
    • 1, 3, 2
    • 1, 1, 1
    • 2, 3, 1

  17. What is the symbol equation for magnesium reacting with hydrochloric acid to give magnesium chloride and hydrogen?

    • Mg + HCl2 -> MgCl2 + H
    • Mg + 2HCl -> MgCl2 + H2
    • Mg + HCl -> MgCl + H2
    • Mg + 2HCl -> MgCl2 + 2H2

  18. Why must a symbol equation keep the same number of each atom on both sides?

    • Because atoms are conserved in a chemical reaction
    • Because the state symbols must match
    • Because symbols show mass only
    • Because products always contain more atoms

  19. Which statement about state symbols is correct?

    • (l) shows a substance that is a solid
    • (aq) shows a substance dissolved in water
    • (s) shows a substance dissolved in water
    • (aq) shows a substance that is a gas

  20. Which equation is balanced for the combustion of methane (CH4) with oxygen to give carbon dioxide and water?

    • CH4 + 2O2 -> CO2 + H2O
    • CH4 + 2O2 -> CO2 + 2H2O
    • CH4 + O2 -> CO2 + 2H2O
    • CH4 + O2 -> CO2 + H2O

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