(i) Explain why you would use a spectrometer rather than a simple flame test to identify the atoms in an unknown mixture.

(ii) When it is present in aqueous solution, the metal strontium, Sr, exists as an ion with a charge of +2. Given this information, state the chemical formula of the metal salt, strontium nitrate.

(iii) Strontium sulfate has a lower solubility in water at 25 °C than calcium sulfate. On the basis of this information, suggest what you would observe when dilute sulfuric acid is added to a solution of strontium nitrate with a concentration of 5 g per 100 g of water at 25 °C. Write down a balanced chemical equation that is consistent with your observation.

(iiv) The addition of a sodium iodide (NaI) solution to a solution of lead nitrate results in the formation of a yellow precipitate of lead iodide. Write down an ionic equation, in which the spectator ions have been removed, for this reaction. You should include the correct state symbols in your equation.