Wrong Past Paper Questions

Question 1

Explain the difference between the processes in electrolysis and in a chemical cell ( 2 marks)

Answer 1

electrolysis uses electricity to produce a chemical reaction (but) cells use a chemical
reaction to produce electricity

Question 2

Explain why alloys are harder than pure metals ( 3 marks)

Answer 2

In an the atoms are of different sizes (so) the layers (of atoms in an alloy) are distorted(so in an alloy) the layers slide over each other less easily (than in a pure metal

Question 3

What insoluble solids can be used to make a copper salt by reacting the solid with dilute hydrochloric acid?

Answer 3

copper carbonate and copper oxide only

Question 4

What is the purpose of warming solution in crystallisation

Answer 4

Speed up reaction

Question 5

Write an ionic equation for the neutralisation of hydrochloric acid with potassium hydroxide.
HCl + KOH

Answer 5

H+ + OH− → H2O

Question 6

Give two observations you could make when a small piece of potassium is added to water (1 mark)

Answer 6

Potassium floats/melts

Question 7

When working out the sum of relative formula mass what number do you ignore big or small

Answer 7

NONE DUMBAH

Question 8

Why does propanone have a low boiling point?

Answer 8

Intermolecular forces are weak

Question 9

What shape is a Buckminsterfullerene molecule?

Answer 9

Sphere

Question 10

Finish half equation
2Br- → +

Answer 10

2Br- →Br2 + 2e-

Question 11

2H-S-H
H-S is 90 kJ/mol
workout out 2H-S-H

Answer 11

There are two H-S bonds
So times by 2 - 180
There are two of this compound
Times by 2 - 360

Question 12

A solution is made by dissolving 1 g of hydrogen chloride in 1 dm3 of water.
Which is the correct description of this solution? ( 1 mark)

Answer 12

Dilute solution of strong acid

Question 13

Give two observations that would be made when zinc carbonate is added to nitric acid
until the zinc carbonate is in excess ( 2 mars)

Answer 13

White solid disappears
Bubbles

Question 14

Plan a method to produce a pure, dry sample of the soluble salt copper chloride from
an acid and a metal oxide 6 marks)

Answer 14

react hydrochloric acid
* (with) copper oxide
* in a suitable container
* warm (hydrochloric) acid
* add copper oxide
* until is in excess
stir
* filter excess copper oxide
* pour solution / filtrate into evaporating basin

Question 15

Explain how oxygen gas is produced in the electrolysis of sodium sulfate solution ( 4 marks)

Answer 15

water molecules
break down to produce OH– ions
(which are) attracted to the
positive electrode
(where OH– ions are) oxidised

Question 16

Suggest why the mass of magnesium oxide produced would be different without a lid
on the crucible (2 marks)

Answer 16

without a lid the) mass of
magnesium oxide was less
(because) products escaped

Question 17

Suggest why a mixture of methane and oxygen does not react at room temperature.
Answer in terms of particles ( 2 marks)

Answer 17

particles collide
(but at room temperature)
particles have insufficient energy

Question 18

Equation for energy released in terms of bond breaking/formed

Answer 18

bonds broken – bonds formed = energy released

Question 19

Three properties of diamond

Answer 19

Very hard
very high melting point
does not conduct electricity

Question 20

Name four substances with giant covalent structures

Answer 20

Graphite
silicon dioxide
Silicon
Graphene

Question 21

Investigation to put this to the test fr
When heated the same mass of any metal carbonate produces
the same mass of carbon dioxide. ( 6 marks)

Answer 21

Weigh test tube
Add metal carbonate
Weigh test tube and metal carbonate
heat - allow to cool
Repeat until no change in mass
Repeat with different metal carbonates