Unit 10 - not in syllabus stuff

Question 1

how are gases separated?

Answer 1

1) air is pumped in a filter
2) CO2 + water vapour is removed
3) air is compressed then cooled
4) air expands once very cold and after several cycles it turns to liquid
5) liquid air is warmed up
6) elements boil off and gases rise up the column according to their boiling points (lowest first)

Question 2

what is rusting?

Answer 2

corrosion by the action of air and water on iron

Question 3

2 factors needed to rust?

Answer 3

water + oxygen

Question 4

rust prevention? [3]

Answer 4

painting with paint / oil
-O2 + H2O cant go through paint
-barrier method

Galvanising
-add zinc metal to outside of iron
–> zinc reacts with oxygen before iron does
-barrier method
-sacrificial protection

Sacrificial protection
-more reactive metal attached to the iron
–> galvanising
–> copper
–> magnesium

Question 5

how to get rid of oxygen in water?

Answer 5

boil water