IGCSE Chemistry SI

Which relative molecular mass Mr, is not correct for the molecule given.

• Ammonia, NH3

• Carbon dioxide, CO2

• Methane, CH4

• Oxygen, O2

The equation represents the action the reaction between sodium iodide and bromine. Balance the equation to show the values of x and y.

• x = 1, y = 2

• x = 2, y = 2

• x = 2, y=1

• x = 4, y = 2

Carbon dioxide and methane both contribute to climate change. Which process produces both gases?

• complete combustion of natural gas

• farming combustion of natural gas

• heating calcium carbonate

• respiration

An element has the following properties. It forms coloured compounds. It acts as a catalyst. It melts at 1539 ˚C. In which part of the Periodic Table is the element found?

• Group I

• Group IV

• Group VII

• Transition elements

What is the relative formula mass, Mr, of CaCO3?

• 50

• 68

• 100

• 204

When sodium reacts with water, a solution and a gas are produced. The solution is tested with litmus paper and the gas is tested with a splint. What happens to the litmus paper and splint?

• Blue to red, Glowing splint relights

• Blue to red, Lighted splint 'pops'

• Red to blue, Glowing splint relights

• Red to blue, Lighted splint 'pops'

Gallium is in Group III and oxygen is in Group VI of the Periodic Table. The formula of gallium oxide is:

• Ga2O3

• Ga3O6

• Ga3O2

• GaO2

Which one of these statements about rusting is true?

• Rust is hydrated iron (II) sulphate.

• Oxygen is needed for rusting but water is not.

• Both air and water are needed for rusting.

• Stainless steel rusts faster than iron.

Complete the digram to show the electronic configuration of a potassium atom (K)

Complete the digram to show the electronic configuration of a potassium ion (K+)