Chemistry Paper 2Q2

1 The rate of diffusion of three gases, ammonia, carbon dioxide and methane, is measured. What is the order of the rate of diffusion of the gases from slowest to fastest?

• CO2 --> NH3 --> CH4
• CO2 --> CH4 --> NH3
• CH4 --> NH3 --> CO2
• NH3 --> CH4 --> CO2

2 Which description of Brownian motion is correct?

• random movement of particles due to bombardment by larger particles
• random movement of particles due to bombardment by smaller particles
• random movement of particles from a high concentration to a low concentration
• random movement of particles from a low concentration to a high concentration

3 The chromatogram obtained using four substances, J, K, L and M, is shown.

Which statement about M is correct?

• It is a mixture of J and K only.

• It is a pure substance.

• It is a mixture of J, K and L.

• It is a mixture of J, K and an unknown substance.

4 Which statements about isotopes of the same element are correct? 1 They are atoms which have the same chemical properties because they have the same number of electrons in their outer shell. 2 They are atoms which have the same number of electrons and neutrons but different numbers of protons. 3 They are atoms which have the same number of electrons and protons but different numbers of neutrons.

• 1 and 2
• 1 and 3
• 2 only
• 3 only

5 Which statement about solid magnesium oxide is correct?

• It is a giant structure made up of magnesium and oxygen atoms bonded covalently.
• It is an electrical conductor with mobile magnesium ions and oxygen ions.
• Magnesium loses electrons and these electrons move freely through a lattice.
• Oxygen ions and magnesium ions are attracted to each other in a giant lattice.

6 Which molecule contains only three shared pairs of electrons?

• CH3OH
• Cl 2
• H2O
• N2

7 Which particles are present in the structure of metals? 1 positive ions 2 negative ions 3 shared pairs of electrons 4 mobile electrons

• 1 and 2
• 1 and 4
• 2 and 3
• 2 and 4

8 Caffeine is a stimulant found in coffee.

Which formula represents caffeine?

• A

• B

• C

• D

9 Which sample does not contain a number of atoms equal to the Avogadro constant?

• 14 g of nitrogen, N2
• 6 g of water, H2O
• 4 g of helium, He
• 28 g of carbon monoxide, CO

10 The electrolysis of concentrated aqueous sodium chloride and molten sodium chloride is shown.

What are the products at electrodes 1 and 2?

• A

• B

• C

• D