Chemistry Form 4 - Chapter 2

Which of the following is an example of diffusion?

• A wet towel dries up when it is left under a running fan.

• The spreading of the smell of perfume from a counter selling cosmetics.

• Spreading of heat from one end of a metal rod to the other end when it is heated.

• Forming of a white precipitate when silver nitrate solution is added to sodium chloride solution.

Which of the following substances contain molecules?

• Zinc

• Ethanol

• Sodium chloride

• Magnesium oxide

Which of the following set of substances consists of all molecules?

• Water, sulphur dioxide, ammonium chloride and carbon monoxide

• Glucose, sodium hydroxide, ammonia and carbon dioxide

• Iodine, glucose, ammonia, and calcium carbonate

• Ammonia, carbon dioxide, glucose and ethanol

The scientist who proposed that the atom consists of electrons orbiting around the nucleus is

• Ernest Rutherford

• James Chadwick

• J.J Thomson

• Neils Bohr

Which of the electron configurations are those of three metals?

• 2.1 2.8.3 2.8.8.2

• 2.2 2.8.1 2.8.7

• 2.8.3 2.8.4 2.8.8.1

• 2.7 2.8.7 2.8.18.7

Isotopes are different atoms with the same number of

• protons, electrons and neutrons.

• electrons but different number of protons.

• protons but different number of neutrons.

• protons and neutrons but different number of electrons.

Which test shows that a sample of water given is pure?

• It boils at 100^oC.

• It dissolves sodium chloride.

• It changes anhydrous copper(II) sulphate from white to blue.

• It reacts with sodium metal to form sodium hydroxide and hydrogen gas.

Ethanol and water can be separated by distillation because they have different

• densities

• solubility

• boiling points

• molecular mass

The nucleon number of sodium atom is 23 and its proton number is 11.

It follows that a sodium atom has

• 11 neutrons

• 11 electrons

• 12 protons

• 23 neutrons

Oxygen and oxide ions

• are isotopes of oxygen

• are chemically identical.

• have the same number of protons.

• have the same number of electrons.