IGCSE Coordinated Chemistry Workout 6

The proton number of element X is 44. Its nucleon number is 145. How many neutrons are there in an atom of X?

• 44

• 101

• 145

• 189

An atom has 2 electrons in its outer shell. Which element could this atom be?

• A

• B

• C

• D

Which material is made from silicon(IV) oxide combined with metal oxides?

• brass

• glass

• polythene

• steel

The apparatus shown is used to investigate the speed of reaction between hydrochloric acid and calcium carbonate.

The time to collect 50 cm³ of gas is measured. Using concentrated acid and lumps of calcium carbonate, the time is 150 s.

In a second experiment, the time is 90 s. Which change was made in the second experiment?

• larger lumps of calcium carbonate

• less concentrated acid

• lower temperature

• powdered calcium carbonate

The table shows physical properties of some substances. Which substance is metal?

• A

• B

• C

• D

A petrochemical molecule undergoes the chemical change shown. What is the chemical change?

• cracking

• polymerisation

• fractional distillation

• reduction

A reagent in solution is added to a solid sample of a fertiliser. The mixture is warmed and the gas given off changes the colour of damp litmus paper.

The test shows that the fertiliser contains ammonium ions.

What is the reagent and what is the original colour of the litmus paper used in the test?

• A

• B

• C

• D

A plant colour X is a mixture. Chromatography is used to compare X with three other coloured mixtures, P, Q and R. The results are shown in the diagram.

Which other mixtures contain the plant colour X?

• P only

• P and Q only

• R only

• P, Q and R

The diagram shows a fire triangle. What are X and Y?

• air and a catalyst

• air and heat

• fuel and a catalyst

• fuel and heat

In separate experiments, an inert wire is dipped into two solutions, P and Q. The wire is then placed in the flame of a Bunsen burner. Solution P turns the Bunsen flame green while solution Q turns it yellow.

What are the identities of P and Q?

• P is copper and Q is potassium

• P is copper and Q is sodium

• P is sodium and Q is copper

• P is sodium and Q is potassium