C2 sheet questions

Question 1

Explain how plate tectonics work and how volcanoes may be formed?

Answer 1

The Oceanic plates are denser and so when they meet with Continental plates are pulled down by subduction. The plates are part of the lithosphere and float on the mantle. They move because of huge convection currents. Volcanoes form where there are weak spots in the crust where two pates meet. Earthquakes are caused by the movements of tectonic plates.

Question 2

Why do most people now accept Wegeners Plate tectonic theory?

Answer 2

Evidence discovered that the tectonic plates were moving apart under the Atlantic Ocean. Scientists discovered convection.

Question 3

Describe with examples how cooling of lava affects crystal size in igneous rocks?

Answer 3

Basalt cools quicker than Gabbro and has smaller crystals.

Question 4

Name some rocks and the problems associated with quarrying them.

Answer 4

Marble, Granite, Limestone.
Can destroy national parks, produce lost of traffic, very noisy.

Question 5

What is concrete?

Answer 5

Calcium Carbonate heated with clay
then sand, aggregate and water are added.

Question 6

What happens when limestone is heated?

Answer 6

A thermal decomposition reaction CaCO3==> CaO + CO2

Question 7

how is limewater (calcium hydroxide made?

Answer 7

calcium oixide + water ==> calcium hydroxide

Question 8

Describe the process of purification of copper (electrolysis)

Answer 8

The solution is copper(ii) sulfate.
The anode is impure copper
The cathode is pure copper
At the anode Electrons are ripped off the copper atoms and they become Cu2+. This is an example of an oxidization
At the cathode Copper ions are deposited on the Cathode which give it 2 electrons, transforming it into copper. This is a reduction.