IGCSE Chemistry Study Guide 2025: Syllabus, Notes & Practice Questions

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IGCSE Chemistry - Study Guide Combined ( Latest 2025

)

State the method used to obtain sand from a mixture of sand

and water .....ANSWER.....filtration

State the method used to obtain solid copper sulfate from

aqueous copper sulfate .....ANSWER.....crystallisation

State the method used to obtain red food dye from a mixture of

food dyes .....ANSWER.....paper chromatography

State the method used to obtain water from salt water

.....ANSWER.....simple distillation

Draw a diagram to show equipment used in simple distillation

.....ANSWER.....For what process is this equipment used?

State the method used to obtain kerosene from a crude oil.

.....ANSWER.....fractional distillation

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Draw the equipment used in fractional distillation in the lab

.....ANSWER.....For what process is this equipment used?

Explain how fractional distillation is used to separate a mixture

of different liquids .....ANSWER.....The different liquids have

different boiling points

State the method used to extract the red dye from a sample of

rose petals .....ANSWER.....dissolving

Describe how pure salt can be obtained from rock salt

.....ANSWER.....1) Grind rock salt into a fine powder. 2) Add

powder to hot water and stir to dissolve salt. 3) Filter mixture.

Salt solution passes through the filter paper leaving behind the

sand. 4) Boil filtrate to evaporate some of the water. 5) Leave

saturated solution to cool so that crystals of salt form. 6) Filter

cold mixture to separate the crystals from the remaining solution.

Ethanol is a flammable liquid. Suggest how it could be heated

safely .....ANSWER.....Use a water bath

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Explain how a chromatogram shows that different dyes are

different from each other .....ANSWER.....Each dyes has a

different mixture

State the expression for calculating molar concentration

.....ANSWER.....Molar concentration = Amount (in moles)/volume

(in dm^³)

Which cation gives a crimson red flame colour? .....ANSWER.....Li⁺

Which cation gives a orange flame colour? .....ANSWER.....Na⁺

Which cation gives a lilac flame colour? .....ANSWER.....K⁺

Which cation gives a brick red flame colour? .....ANSWER.....Ca²⁺

Describe how you would carry out a flame test .....ANSWER.....Put

solid onto a wire. Put into a blue flame

How would you test for the ammonium ion? .....ANSWER.....Add

sodium hydroxide. If ammonium ions were present, ammonia gas

will form which will turn damp red litmus paper blue

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Describe how you would test for Cu²⁺ ions .....ANSWER.....Add

sodium hydroxide and a blue precipitate will form

Give the formula of the blue precipitate formed when sodium

hydroxide is added to a solution containing Cu²⁺

.....ANSWER.....Cu(OH)₂

Describe how you would test for Fe²⁺ ions .....ANSWER.....Add

sodium hydroxide and a green precipitate will form

Write a word equation for the reaction between sodium

hydroxide and iron(II) sulfate .....ANSWER.....sodium hydroxide +

iron(II) sulfate -> iron (II) hydroxide + sodium sulfate

Describe how you would test for Fe³⁺ ions .....ANSWER.....Add

sodium hydroxide and a brown precipitate will form

What 2 things are added to a solution to test for chloride ions?

What is observed if they are present? .....ANSWER.....Add dilute