Paper 1 - Mistakes Flashcards
Explain why hot water evaporates more quickly than cold water [2 marks]
- have more energy
- so they can break water molecule bonds
test for ammonium
[2 marks]
- sodium hydroxide
- litmus - red to blue
2 reason why it takes several minutes for the ammonium chloride to form
[3 marks]
- collide with walls
- collide with air
- move in random directions
covalent bond
[3 marks]
- electrostatic forces of attraction between
- positive nuclei
- negatively charged shared pair of electrons
Describe arrangement and movement of gas
[3 marks]
- space between particles
- move quickly
- move freely
- no regular pattern
Why does zinc prevent rusting on iron cars
[2 marks]
- Zinc is more reactive than iron cars
- so the water and oxygen react with zinc not iron
Why is cracking important for oil industry?
[3 marks]
- crude oil produces mostly long chain molecules
- short chain more useful (because more flammable)
- short chain used to make polymers
Describe a method to show that solid maganese oxide is a catalyst
[3 marks]
- filter
- leave to dry
- weigh - should be same weight
Combustion of common impurities may cause environmental concern [3 marks]
- sulphur
- leads to sulphur dioxide
- acid rain
Catalyst and temperature for cracking
- silica/alumina
- 600-700
Cracking produces:
- an alkane
- two alkenes
How does increasing concentration affect rate of reaction [3 marks]
- more particles of HCL in same volume
- more particles for collisions
- more successful collisions
- faster rate
How does increasing SA affect rate [3 marks]
- speeds up
- larger SA
- more successful collisions
Why is this molecule a compound [2 marks]
- two or more different elements
- which are bonded together
Why is oxygen calculation not accurate [2 marks]
- was left to finish reacting
- apparatus not left to cool
- leak in apparatus
Why does sodium oxide not conduct? [2 marks]
- ionic structure
- so electrons and ions cannot flow
- no delocalised electrons
Why use equal amounts of moles of product [1 mark]
- make sure they fully react so that there is the highest percentage yield
Isomer [2 marks]
- same molecular formula
- different structural
Issue with disposing addition polymers [1 mark]
- landfills are getting full - no more space
- burning them releases toxic GHGs
Discuss environmental issues with addition polymers
Landfill
- doesn’t decompose
- landfill gets full
Burning
- toxic gases
- GHGs
- Climate change
Why do giant ionic compounds have high melting points
- electrostatic forces of attraction
- between oppositely charged ions
- are very strong
- therefore require a lot of energy to overcome
Why does boiling point increase down group 7
- more electron shells
- stronger intermolecular forces
Test for water
Physical - boil 100 c
Chemical - anhydrous copper sulphate - white to blue
Why don’t you evaporate all water in a salt prep? [1 mark]
- becomes anhydrous and doesn’t form crystals
