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1

what are the properties of transition metals

hard, shiny, strong, malleable materials that conduct heat and electricity well, high mp (except mercury which is a liquid at room temperature)
the same properties as metals
they also have a high density for example potassium a group 1 metal is 0.9gcm to the -3 while copper has a density of 9.0gcm to the -3 / higher density at room temperature

2

what are the uses of transition metals

shiny and malleable = jewellery
electrical conductor and corrosion resistant = electrical components
malleable and corrosion resistant = copper water pipes
electrical conductor = electrical wiring

3

what do transition metals make a good one of

transition metals and their compounds make good catalysts
iron in Haber process for making ammonia
vanadium pentoxide used in the contact process to make sulfuric acid

4

what does a catalyst do

speeds up the rate of reaction without being changed or used up itself

5

what should you be aware of with transition metals

they form very colourful compounds

6

why are pure metals malleable and what does this mean

because they have a regular arrangement of identical atoms so the layers of ions can easily slide over each other which means they aren't strong enough for certain uses so alloys are used instead

7

how are alloys made and why are they stronger than pure metals

alloys are made by adding another element to a metal - this can be a non-metal or a metal
different elements have different sized atoms so for example when carbon is added to iron the smaller carbon particles will upset the layers of pure iron atoms making it more difficult for them to slide over each other so they are stronger

8

what are alloys of iron called and how do we make them

steels
add small amounts of carbon to the pure iron
steel is harder than iron and stronger as long as the carbon doesn't exceed more than about 1%
its much less likely to corrode (rust) than pure iron

9

what things are made from general steel

girders, bridges, engine parts, cutlery, washing machines, pans, ships, tools and cars

10

what are the properties of
low carbon steel (0.1-0.3% carbon)
high carbon steel (0.22-2.5% carbon)
stainless steel (chromium added and sometimes nickel)

easily shaped

very strong, inflexible, brittle

corrosion-resistant, strong

11

give some alloys

bronze = copper + tin
medals, decorative ornaments and statues - harder than copper
brass = copper + zinc
brass in more malleable than bronze and is used when lower friction is required such a in water taps and door fittings
gold alloys for jewellery to strengthen it
aluminium alloys in aircrafts because it has a low density but pure aluminium isn't strong enough
magnalium = aluminium + magnesium
cars parts and aeroplane parts
stronger, lighter, less corrosive when small magnesium
higher amounts of magnesium make fireworks as reactive and burns easily

12

what is corrosion

when something is slowly damaged or destroyed by a chemical process

13

what is the rusting of iron

a redox reaction - the corrosion of iron and only happen when they iron is in contact with oxygen from the air and water

14

discuss corrosion

metals can corrode when in the presence of water and oxygen to form their metal oxides
the corrosion of metals is caused by their redox reactions
the metal loses electrons so is oxidised and simultaneously the oxygen gains electrons when it reacts with the metal

15

OIL RIG

oxidation
is
loss

reduction
is
gain

16

how can you show that oxygen and water are both needed for iron to rust

3 test tubes with a nail in
1 - boiling water (removes oxygen) and a layer of oil to stop air getting in
2 - air and calcium chloride to absorb water in the air
they both wont rust
3 - air and water will rust the iron

17

how can you prevent rusting/corrosion of iron

with a barrier that keeps out either water, oxygen or both
1. coat with a barrier
2. painting
3. oiling or greasing must be used when using moving parts like a bicycle chain
4. sacrificial protection where you place a more reactive metal with the iron so it will react with water and oxygen instead of the object your protecting
5. galvanising is an example of sacrificial protection where a coat of zinc is put onto an iron object to prevent it rusting. The zinc is more reactive so it will lose electrons and corrode in preference to iron
steel buckets and corrugated iron roofing are often galvanised

18

what is electroplating

coating the surface of a metal with another metal using electrolysis
the cathode is the object your going to electroplate and the anode is the bar of metal your using for the plating
your electrolyte is a solution containing the metal ions of the metal your plating

19

why is electroplating useful

because it stops household items like cutlery and cooking utensils from corroding as the metals used for protection are unreactive and don't corrode easily
jewellery and decorative items are often electroplated with metals like gold and silver as it approves the appearance of the metals making them look shiny and attractive

20

how would you electroplate silver onto a brass cup

the cathode is the brass cup and the anode is the bar of silver
the electrolyte is silver nitrate solution (AgNO3)
the silver ions from the electrolyte move towards the cathode (brass cup) and the metal gets deposited on the brass cup
the anode keeps the silver ions in the solution 'topped up'
cathode - Ag+ + e- -> Ag
anode - Ag -> Ag+ + e-

21

why do we use titrations

because they allow you to find out exactly how much acid is needed to neutralise a given quantity of alkali or vice versa

22

what is the method for titration

using a pipette measure our 25cm squared of alkali into a flask. add a few drops of phenolphthalein or methyl orange
fill a burette with a standard solution ( a know concentration of acid)
keep the burette below eye level so your not looking up if any acid spills
use the burette to add the acid to the alkali a bit at a time. Swirl the flask regularly, go slowly ( a drop at a time) when you think the alkali's almost neutralised.
stand your flask on a white tile so you can see the colour change easily
do a rough titration where you note the approximate amount of acid you need then go slowly as you near the amount of the next runs
the indicator changes colour when all the alkali has neutralised - phenolphthalein is pink in alkali and colourless in acids
methyl orange is yellow in alkali but red in acids
record the volume of acid used to neutralise the alkali (titre)
repeat all the above then get a mean

23

formula for concentration

concentration = number of moles divided by volume of solution
c = n divided by v
mol dm to the -3 = mol divided by dm cubed

you can use the results of the titration experiment to calculate the concentration of the alkali when you know the conc of the acid or vice versa

24

what is percentage yield

actual yield divided by theoretical yield x100

25

what is the theoretical yield of a reaction

the mass of product you'd make if all the reactants were converted to products and can be calculated by the balanced reaction equation

26

why do we never get 100% yield

incomplete reactions if not all reactants converted to products

lose liquid if you transfer chemicals between containers because some always left on inside surface

unwanted reactions by impurities or conditions

insufficient oxygen

reversible reaction could have taken place

27

atom economy

total Mr of desired products divided by total Mr of all products x100

the higher the atom economy the greener the process

28

discuss reactions with a low atom economy

use up resources quickly
makes lots of waste materials that need to be disposed of
unsustainable
not profitable
raw materials are expensive
need uses for waste products

29

what factors must you consider in industry

percentage yield
atom economy
rate of reaction
if your reaction is reversible

30

what is the test for chlorine

damp blue litmus paper turns red then bleaches white