Paper 1 - Mistakes

Question 1

Explain why hot water evaporates more quickly than cold water [2 marks]

Answer 1

• have more energy
• so they can break water molecule bonds

Question 2

test for ammonium
[2 marks]

Answer 2

• sodium hydroxide
• litmus - red to blue

Question 3

2 reason why it takes several minutes for the ammonium chloride to form
[3 marks]

Answer 3

• collide with walls
• collide with air
• move in random directions

Question 4

covalent bond
[3 marks]

Answer 4

• electrostatic forces of attraction between
• positive nuclei
• negatively charged shared pair of electrons

Question 5

Describe arrangement and movement of gas
[3 marks]

Answer 5

• space between particles
• move quickly
• move freely
• no regular pattern

Question 6

Why does zinc prevent rusting on iron cars
[2 marks]

Answer 6

• Zinc is more reactive than iron cars
• so the water and oxygen react with zinc not iron

Question 7

Why is cracking important for oil industry?
[3 marks]

Answer 7

• crude oil produces mostly long chain molecules
• short chain more useful (because more flammable)
• short chain used to make polymers

Question 8

Describe a method to show that solid maganese oxide is a catalyst
[3 marks]

Answer 8

• filter
• leave to dry
• weigh - should be same weight

Question 9

Combustion of common impurities may cause environmental concern [3 marks]

Answer 9

• sulphur
• leads to sulphur dioxide
• acid rain

Question 10

Catalyst and temperature for cracking

Answer 10

• silica/alumina
• 600-700

Question 11

Cracking produces:

Answer 11

• an alkane
• two alkenes

Question 12

How does increasing concentration affect rate of reaction [3 marks]

Answer 12

• more particles of HCL in same volume
• more particles for collisions
• more successful collisions
• faster rate

Question 13

How does increasing SA affect rate [3 marks]

Answer 13

• speeds up
• larger SA
• more successful collisions

Question 14

Why is this molecule a compound [2 marks]

Answer 14

• two or more different elements
• which are bonded together

Question 15

Why is oxygen calculation not accurate [2 marks]

Answer 15

• was left to finish reacting
• apparatus not left to cool
• leak in apparatus

Question 16

Why does sodium oxide not conduct? [2 marks]

Answer 16

• ionic structure
• so electrons and ions cannot flow
• no delocalised electrons

Question 17

Why use equal amounts of moles of product [1 mark]

Answer 17

• make sure they fully react so that there is the highest percentage yield

Question 18

Isomer [2 marks]

Answer 18

• same molecular formula
• different structural

Question 19

Issue with disposing addition polymers [1 mark]

Answer 19

• landfills are getting full - no more space
• burning them releases toxic GHGs

Question 20

Discuss environmental issues with addition polymers

Answer 20

Landfill
- doesn’t decompose
- landfill gets full

Burning
- toxic gases
- GHGs
- Climate change

Question 21

Why do giant ionic compounds have high melting points

Answer 21

• electrostatic forces of attraction
• between oppositely charged ions
• are very strong
• therefore require a lot of energy to overcome

Question 22

Why does boiling point increase down group 7

Answer 22

• more electron shells
• stronger intermolecular forces

Question 23

Test for water

Answer 23

Physical - boil 100 c
Chemical - anhydrous copper sulphate - white to blue

Question 24

Why don’t you evaporate all water in a salt prep? [1 mark]

Answer 24

• becomes anhydrous and doesn’t form crystals

Question 25

Copper Carbonate colour

Answer 25

Green

Question 26

Copper Oxide

Answer 26

Black

Question 27

Difference between movement of particles in solids and gases? [2 marks]

Answer 27

Solids - vibrate around a fixed position
Gases - move freely and randomly

Question 28

Conditions required for substitution reaction [1 mark]

Answer 28

UV

Question 29

Test for chlorine gas

Answer 29

• litmus paper
• turns white

Question 30

Magnesium crucible experiment - why open lid

Answer 30

• allow oxygen in
• so it can react