IGCSE Multi Choice Nov 2021

Decane has a freezing point of –30 °C and a boiling point of 174 °C. A small sample of decane is placed in an open beaker in an oven at a temperature of 120 °C and at atmospheric pressure for 24 hours. What happens to the sample of decane?

• It boils

• It evaporates

• It melts

• It sublimes

A student put exactly 25.00 cm³ of dilute hydrochloric acid into a conical flask. The student added 2.5 g of solid sodium carbonate and measured the change in temperature of the mixture. Which apparatus does the student need to use?

• balance, measuring cylinder, thermometer

• balance, pipette, stopwatch

• balance, pipette, thermometer

• burette, pipette, thermometer

A student separates sugar from pieces of broken glass by dissolving the sugar in water and filtering off the broken glass. What is the filtrate?

• broken glass only

• broken glass and sugar solution

• pure water

• sugar solution

Which statement explains why metals conduct electricity when solid?

• They have atoms which are free to move.

• They have electrons which are free to move.

• They have molecules which are free to move.

• They have positive ions which are free to move.

Which description of brass is correct?

• Alloy

• Compound

• Element

• Non-metal

The equation for the reaction of iron(III) oxide with carbon monoxide is shown.

• 56 g

• 112 g

• 168 g

• 336 g

Which statement describes the attractive forces between molecules?

• They are strong covalent bonds which hold molecules together.

• They are strong ionic bonds which hold molecules together.

• They are weak forces formed between covalently-bonded molecules.

• They are weak forces which hold ions together in a lattice.

Which statement about carbon is correct?

• Diamond and graphite both have simple molecular structures.

• Diamond and graphite are both used to make cutting tools.

• Each carbon atom in diamond is bonded to three other carbon atoms.

• Graphite conducts electricity and has a giant covalent structure.

The formula of an aluminium ion is Al³⁺. What is the formula of aluminium sulfate?

• Al₂SO₄

• Al(SO₄)₂

• Al₂(SO₄)₃

• Al₃(SO₄)₂

Which statements about the products of electrolysis, using inert electrodes, are correct?

• 1 and 2

• 1 and 3

• 2 and 4

• 3 and 4