Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Edexcel Chemistry > Topic 5- Separate chem I > Flashcards

Topic 5- Separate chem I Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What is corrosion ?

A
  • when a metal oxidises – usually given to iron or steel

- example of redox reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How to prevent rusting?

A
  • painting -same as oil or grease
  • oil or grease - forms protective coat around metal
  • coating w/ plastic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does galvanising iron protect it from corrosion

A
  • zinc more reactive than iron so reacts instead of iron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does sacrificial protection protect iron from corrosion

A
  • more reactive metal connected to iron, so corrodes instead
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does tin plating iron protect it from corrosion

A
  • tin coat protects iron underneath
  • less reactive, so acts as barrier – if tin scratched iron will rust
  • quite cheap
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does alloying iron protect it from corrosion

A
  • other elements increase corrosion resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Percentage yield equation

A

percentage yield = yield obtained/ predicted yield x 100 (for percentage)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the yield of a reaction?

A
  • amount of chemicals produced during during a reaction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does aluminium seem to not corrode?

A
  • When corrodes forms protective layer of aluminium oxide – happens very quickly – when scratched will form layer again
  • layer doesn’t allow air or water to pass through
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is atom economy?

A
  • amount of atoms wasted or lost when a chemical is made
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

atom economy equation

A

atom economy = mass of atoms in desired product/ total mass of all products x100 – for percentage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is electroplating?

A
  • acts as barrier to oxygen and water
  • can electroplate a metal with an unreactive
    metal that is more attractive and will not corrode e.g. gold
  • it’s done using the metal to be plated as cathode and metal you’re plating it with is the anode
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an alloy?

A

-a mixture of a metal w/ one or more other elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does an alloy increase the strength of a product?

A
  • have + ions of different metals, that have different sized ions– disrupts regular structure and stops ions being able to slide as easily, so leaves much
    harder, stronger metal.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why iron alloyed to make steel

A
  • steals mixture of carbon and iron
  • Low-carbon steels are malleable so used for sheeting
  • High carbon steels are hard - used for cutting tools
  • Stainless steels w/ chromium and nickel are resistant to corrosion - used for cutlery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Uses of aluminium

A

low density, used for aircraft

17
Q

uses of copper

A

good conductor, used in electrical cables

18
Q

uses of gold

A

good resistance to corrosion, used in jewellery

19
Q

uses of magnalium

A

(aluminium + magnesium): low density, used in cars and planes

20
Q

uses of brass

A

(copper + zinc): hard, resistant to corrosion, used in coins

21
Q

calculate concentration (mol dm^-3)

A

concentration = no. of moles (mol) / volume (dm^3)

22
Q

Percentage yield equation

A

percentage yield = yield obtained/ predicted yield x 100

23
Q

What causes the actual yield being less than the predicted yield

A
  • incomplete reactions
  • practical losses during the experiment
  • side reactions
24
Q

What is atom economy?

A
  • amount of starting materials that end up as useful products
25
Q

atom economy equation

A

Relative molecular mass of desired product from reaction / sum of molecular mass (Mr) of all reactants

26
Q

Volume of gas at room temp. ( dm^3)

A

mol. x 24

27
Q

What is Avogadro’s law

A

one mole of a substance contains 6.02 x 10^23 particles

- so if you had 10 moles of a substance, you’d do 10 x 6.02 x 10^23

28
Q

Benefits of atom economy

A
  • Efficient processes have high atom economies, and are important for sustainable development, they use fewer natural resources and create less waste.
29
Q

What is the Haber process ?

A
  • a reversible reaction between nitrogen
    and hydrogen to form ammonia using an iron catalyst at high temperature and pressure.
  • 200 atmospheres
  • 450 degrees temp.
30
Q

When is equilibrium reached at a faster rate

A
  • higher temp. is used (particles have more kinetic energy so collide more frequently so have more successful collisions)
  • higher pressure/concentration is used (more particles in a given volume, so more frequent successful collisions)
  • catalyst is used - speed up rate of reaction
31
Q

How is the Haber process affected by cost of raw materials and other external factors

A
  • a higher temp. shifts equilibrium towards the reactants forwards reaction is exothermic,compromise required
    to create a fast rate of reaction and a high yield of products
  • Catalyst can be expensive
  • High temp. and pressures can be expensive and dangerous and equipment required for them can be very
    expensive
32
Q

Describe how the Haber process works

A
  • the purified gases (nitrogen and hydrogen) are passed over iron catalyst at high temp. (about 450 °C) and high pressure (about 200 atmospheres).
  • reaction mixture is then cooled and condensed into liquid and is used in fertilisers (fertilisers can contain nitrogen, phosphorus and potassium)
33
Q

How does ammonia react with nitric acid

A

-ammonia acts as a base
ammonia + nitric acid -> ammonium nitrate
- NH3 + HNO3 → NH4NO3

34
Q

production of ammonium sulphate in the industry

A
  • reactants:are natural gas, air, water (to make ammonia) and sulphur, air, water (to make sulfuric acid)
  • on a large scale
  • are many stages required
35
Q

production of ammonium sulphate in a lab

A
  • reactants are ammonia solution and dilute sulfuric acid (bought from chemical manufacturers)
  • on a small scale
  • involves a few stages
36
Q

describe what happens in a hydrogen-oxygen fuel cell

A
  • Supplied by hydrogen and oxygen (or air)
  • reaction takes place within the fuel cell to produce a potential difference
  • Overall reaction in a hydrogen fuel cell involves the oxidation of hydrogen to produce water
    o 2H2 + O2 → 2H2O
37
Q

strengths of a fuel cell

A
  • produce only water as waste
    -keep producing fuel if fuel keeps being
    supplied
38
Q

weaknesses of a fuel cell

A
  • expensive to make

- difficult to transport/store hydrogen so aren’t suitable for portable devices

39
Q

What happens during a chemical cell

A
  • chemical cells produce a voltage until one of the
    reactants is used up
  • Chemical reactions stop when one of the reactants has been used up

Edexcel Chemistry (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions