Past Paper Extras

Question 0

Conditions for cracking

Answer 0

Heat and catalyst

Question 1

Formula for iron 3

Answer 1

Fe(OH)3

Question 2

What colour is bromine water

Answer 2

Orange

Question 3

What turns bromide water from orange/brown and to what colour

Answer 3

Alkene. Colourless

Question 4

What is a thermosoftening polymer

Answer 4

Thermosoftening polymers soften when heated and can be reshaped, there shape will harden when cooled

Question 5

What is a thermosetting polymer

Answer 5

A thermosetting polymer, once moulded do not change shape when heated or reshaped. There chains are crossed linked so cannot slide past each other

Question 6

How is crude oil separated in fractional distillation

Answer 6

> heated and evaporates
column cooler at the top
different fractions have different boiling points
condense at different places in the column

Question 7

Why do ionic compounds have high melting points

Answer 7

> strong forces of attraction
between oppositely charged ions
which need a lot of energy to break

Question 8

Why does a molten substance carry electricity but not a solid substance

Answer 8

> current carried by ions
which can move when molten
but can’t move when solid

Question 9

Explain why alloys are harder than a pure substance

Answer 9

The atoms are not able to slide over each other

Giving it a more solid structure

Question 10

Why does a rate of reaction decrease

Answer 10

Because the concentration is lower

So there are fewer collisions per second

Question 11

Define relative formula mass

Answer 11

All the relative atomic masses of the atoms contained in a compound