C3.4 Analysis and Synthesis
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State the colour for the flame test of a Lithium Ion (Li+)
Crimson/red
State the colour for the flame test of a Sodium Ion (Na+)
Orange
State the colour for the flame test of a Potassium Ion (K+)
Lilac/Purple
State the colour for the flame test of a calcium ion (Ca2+)
red
State the colour for the flame test of a Barium Ion (Ba2+)
Green
State the observation when a few drops of sodium hydroxide is added to iron (II) chloride
green precipitate/solid
State the observation when a few drops of sodium hydroxide is added to iron (III) chloride
brown precipitate/solid
State the observation when a few drops of sodium hydroxide is added to copper chloride
blue precipitate/solid
State the observation when a few drops of sodiurecipitate/solidm hydroxide is added to calcium chloride
white precipitate/solid
State the observation when a few drops of sodium hydroxide is added to magnesium chloride
white precipitate/solid
State the observation when a few drops of sodium hydroxide is added to aluminium chloride
white precipitate/solid
State the observation when an excess of sodium hydroxide is added to aluminium chloride
precipitate dissolves/disappears
Describe how to distinguish between calcium and magnesium ions
flame test calcium ions give a red flame
Describe the test for carbonate ions
Add an acid Bubbles of carbon dioxide which turns limewater cloudy
Describe the test for sulphate ions
Add barium chloride makes a white precipitate (solid)
Describe the test for chloride ions
Add silver nitrate makes a white precipitate (solid)
Describe the test for bromide ions
Add silver nitrate makes a cream precipitate (solid)
Describe the test for iodide ions
Add silver nitrate makes a yellow precipitate
Give two advantages of using instrumental methods of analysis. [1]
fast sensitive accurate
Describe how to use apparatus to do a titration using 25 cm3 of dilute hydrochloric acid. In your answer you should include: • how you will determine the end point of the titration • how you will make sure the result obtained is accurate. [4]
• put sodium hydroxide (alkali) in the burette • add drop wise until the indicator turns pink • whilst swirling • read at the meniscus • read the start and end volumes
What is meant by a closed system?
nothing can enter and nothing can leave the reaction
Explain why, when a reversible reaction reaches equilibrium, the reaction appears to have stopped. [2]
forward and backward reactions have same rate [1] so there is no (overall) change in concentration of reactants and products [1]
Name a natural resource from which hydrogen is produced for the Haber process
methane (natural gas)
What happens to the amount of ammonia produced at equilibrium if the pressure is increased? Give a reason for your answer. [2]
the amount (of ammonia) increases [1] the equilibrium moves to the side (of the equation) with fewer (gaseous) molecules / moles [1]