IGCSE Practice...again

Which change of state takes place during evaporation?

• gas to liquid

• liquid to gas

• liquid to solid

• solid to gas

The diagram shows apparatus being used to demonstrate how the rate of a chemical reaction changes with temperature. Which statement must be correct?

• The reaction is endothermic.

• The reaction is exothermic.

• The reaction produces a gas.

• The reaction produces an acid.

The table shows the nucleon number and the number of neutrons in one atom of isotopes W, X, Y and Z. Which statement about W, X, Y and Z is correct?

• W and X are isotopes of the same element.

• X and Y are isotopes of elements in the same group of the Periodic Table.

• Y and Z are isotopes of elements in the same period of the Periodic Table.

• Z has a higher proton number than Y

Compound X melts at 801°C and is a good electrical conductor when dissolved in water. Compound Y boils at 77°C, in insoluble in water and is a non-conductor.

• A

• B

• C

• D

What do the nuclei of ¹H hydrogen atoms contain?

• electrons and neutrons

• electrons and protons

• neutrons only

• protons only

The electronic structures of atoms X and Y are shown. X and Y form a covalent compound. What is its formula?

• XY₅

• XY₃

• XY

• X₃Y

The relative atomic mass of chlorine is 35.5. When calculating relative atomic mass, which particle is the mass of a chlorine atom compared to?

• a neutron

• a proton

• an atom of carbon-12

• an atom of hydrogen-1

The diagram shows the electrolysis of concentrated HCl and concentrated aqueous NaCl using carbon electrodes. At which electrode(s) is hydrogen produced?

• electrode 1 only

• electrodes 1 and 3

• electrode 2 only

• electrodes 2 and 4

The diagram shows a section of an overhead power cable. Which statement explains why a particular substance is used?

• Aluminium has a low density and is a good conductor of electricity.

• Ceramic is a good conductor of electricity.

• Steel can rust in damp air.

• Steel is more dense than aluminium.

H₂ can be used as a fuel. 1-H₂ is expensive to produce, 2-H₂ reacts exothermically with oxygen, 3-When H₂ burns, a greenhouse gas is not formed.

• A

• B

• C

• D