1C June 2012

Question 1

State the colour change in this reaction: Cl2 + 2Br− = 2Cl− + Br2

Answer 1

Colourless to orange.

Question 2

Chemical equation for the decomposition of hydrogen peroxide?

Answer 2

2H2O2 -> 2H20 + O2

Question 3

State two changes that occur during the formation of poly(ethene).

Answer 3

One of the bonds in the double bond breaks, many monomers join together.

Question 4

Explain why cracking is an important process in the oil industry?

Answer 4

Produces smaller molecules, smaller are more useful. Smaller molecules burn more cleanly. Produces alkenes, which are used to make alcohol.

Question 5

Explain why silicon dioxide reacts with calcium oxide?

Answer 5

Silicon dioxide is acidic and calcium oxide is basic.

Question 6

One negative ion that cannot be identified by a precipitation reaction?

Answer 6

Nitrate.

Question 7

Why is silver removed from lead in the blast furnace?

Answer 7

It is valuable.