Paper 3

Question 1

Test for Carbonate ions (include observations)

Answer 1

• Dilute acid (HCL)

- Effervescence (fizzing CO2 bubbles released)

Question 2

Test for sulfate Ions

Answer 2

• Add Nitric acid to remove Carbonate impurities
• Add Barium chloride/nitrate to react with the sulfate ions
• WHITE PRECIPITATE of Barium Sulfate forms (BaSO4)

Question 3

Flame Tests Colours

Answer 3

Go and check the “Flame Tests” in this deck and revise them

Question 4

Why might carrying a flame test on a mixture not show that there are different metals present in the mixture?

Answer 4

-The Strong colours can mask the other colours

Question 5

Give a reason why carrying out a flame test on a mixture of potassium chloride
and strontium chloride does not clearly show that two different metal ions
are present.

Answer 5

• The strong crimson red colour of Strontium can mask the lilac colour of potassium

Question 6

How can you ensure that all of the reactant is transferred into the flask?

Answer 6

• Rinse the equipment used into the flask

- transfer the washings to the (volumetric) flask

Question 7

A student adds deionised water above the mark and shakes the flask.
State why the procedure has to be restarted rather than using a teat pipette
to remove the excess water.

Answer 7

• Changes the concentration to an unknown value