10 Cambridge- IGCSE Chemistry-19.04

Substance Q was investigated using chromatography.

The chromatogram is shown. The diagram is not drawn to scale.

What is the R_f value of Q?

• 0.60

• 0.64

• 0.69

• 0.72

Which statement describes the structure of copper?

• It has a lattice of negative ions in a ‘sea of electrons’.

• It has a lattice of negative ions in a ‘sea of protons’.

• It has a lattice of positive ions in a ‘sea of electrons’.

• It has a lattice of positive ions in a ‘sea of protons’.

River water contains soluble impurities, insoluble impurities and bacteria.

River water is made safe to drink by filtration and chlorination.

Which statement is correct?

• Filtration removes bacteria and insoluble impurities, and chlorination removes soluble impurities.

• Filtration removes insoluble impurities, and chlorination kills the bacteria.

• Filtration removes soluble impurities, and chlorination kills the bacteria.

• Filtration removes soluble impurities and bacteria, and chlorination removes insoluble

  impurities.

Which process is used to separate nitrogen and oxygen from air?

• chromatography

• evaporation

• filtration

• fractional distillation

The diagram represents an outline of the carbon cycle.

Which processes are X and Y?

• X: combustion

  Y: respiration

• X: decomposition

  Y: respiration

• X: photosynthesis

  Y: combustion

• X: respiration

  Y: combustion

The diagram shows the structure of a monomer and of the polymer made from it.

• monomer: ethane

  polymer: poly(methane)

• monomer: ethane

  polymer: poly(ethene)

• monomer: ethene

  polymer: poly(methane)

• monomer: ethene

  polymer: poly(ethene)

Pure water boils at 100 °C.

What happens to the water particles when water boils?

• They gain energy and move further apart.

• They gain energy and stay close together.

• They lose energy and move further apart.

• They lose energy and stay close together.

Which describes isotopes of the same element?

• they have different number of protons and different number of neutrons

• they have different number of protons and same number of neutrons

• they have same number of protons and different number of neutrons

• they have same number of protons and same number of neutrons

Which substance is not produced during the electrolysis of concentrated aqueous

sodium chloride?

• chlorine

• hydrogen

• sodium

• sodium hydroxide

Aqueous copper(II) sulfate is electrolysed using copper electrodes.

What is the ionic half-equation for the reactions that occur at negative electrode?

• Cu → Cu²⁺ + 2e

• Cu²⁺ → Cu + 2e

• Cu²⁺ + 2e → Cu

• Cu + 2e → Cu⁺²