C1-4 Chemical Equations

Chemical changes are shown using chemical equations. One way to show a chemical reaction is to use a word equation. Which of the following examples is a word equation showing a chemical reaction?

• Methane burns in oxygen to give carbon dioxide and water.

• Methane reacting with oxygen shows complete combustion.

• methane + oxygen -> water + carbon dioxide

• methane is a hydrocarbon

Chemical equations show products and reactants but which is which?

• Products are on the left and reactants are on the right.

• Products are produced in a chemical reaction.

• Reactants are on the left and products are on the right.

• Products are on the right in a chemical reaction.

Which of these shows the correct symbols equation for the reaction of magnesium with oxuygen?

• Mg + O2 -> MgO

• Mg + O -> MgO

• MG + O2 -> MGO

• 2Mg + O2 -> 2MgO

There are four state symbols used in chemical equations, the state symbol (s) means the substance is a ...

There are four state symbols used in chemical equations, the state symbol (aq) means the substance is ...

There are four state symbols used in chemical equations, the state symbol (g) means the substance is a ...

There are four state symbols used in chemical equations, the state symbol (l) means the substance is a ...

Which of these shows a correctly balanced equation?

• CH4 + O2 -> CO2 + H2O

• H2SO4 + NaOH -> Na2SO4 + H2O

• H2 + 2O -> H2O

• 2Na + Cl2 -> 2NaCl

Hydrogen and oxygen gases are formed when water undergoes electrolysis. Which answer shows both the correct word equation and the correctly balanced chemical equation for the reaction?

• water -> hydrogen + oxygen

  H2O -> H2 + O2

• water -> hydrogen + oxygen

  H2O -> H2 + O

• water -> hydrogen + oxygen

  H2O2 -> H2 + O2

• water -> hydrogen + oxygen

  H2O -> 2H + O

Which of these equations is NOT correct?

• 2H2 + O2 -> 2H2O

• 2Na + F2 -> 2NaF

• CH4 + 2O2 -> CO2 + 2H2O

• Fe + Cl3 -> FeCl3