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AQA GCSE Chemistry Unit 2 24 May 2012

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Im feeling this way but i need it to study dentistry

Its all.about doing whatever is necessary if you want it you have to work for it

This was posted from The Student Room's Android App on my GT-I9100

Reply 161

xoxlovelifexox

Original post by diggy

if it's based on the exam today then i wouldn't really hold it against yourself, mainly for what you said but also sometimes you do much better than you think you have.

Reply 162

lfc_all_day

hi i think i did really bad in this test i got around 25- 31 marks but i got i think 30 - 33 in biology and 100 ums in my ISA i still have physics on the 30th does anybody know how many marks i will need to get an A overall or is it out of reach please reply thankyou

p.s im doing additional not triple

Reply 163

khalidpatel

its been 6 hours and we ain got a bloody mark scheme up WOW c'mon guysssss

Reply 164

Aidanb90

Original post by jones2596

I wrote evaporation...not sure if that's right though.

What did other people get?

There was two similar questions, the one directly after the precipitate question was filtration,
then there was one about a salt solution, that one was evaporation.

Reply 165

hello my name is

how can that be it says 2 grams of nitrogen how can u make more then two grams :confused:

Reply 166

MissGeek

Hi everyone, below is an unofficial mark scheme for question 1 (all the questions and answers I remember), if you remember any which I have missed out, then please say so

1a) Why are chloride ions attracted to the positive electrode? (1)
Opposite charges attract/chloride ions have a negative charge
1b) I can't remember, I think it was something on ions, or alkalis? (1)
1c) Why is hydrogen formed? (1)
Hydrogen is less reactive than sodium
1d) Draw the diagram (Hydrogen and Chlorine) (I THINK) (1)
Both must have a full outer shell.
1e) What type of bonding is it? (1)
Covalent

I may start an unofficial mark scheme for question 2, can someone please remind me of the questions, so I can refresh my memory

Thank You

Reply 167

stylishpop

I thought i did ok but looking at your guys answers now im not too sure.... :/

Reply 168

IgorYakov

Original post by hello my name is

how can that be it says 2 grams of nitrogen how can u make more then two grams :confused:

As you have your 6 moles of Hydrogen as well ;o

Reply 169

hello my name is

Original post by HopelessTurtle

What did you get for the question about the maximum amount of ammonia that can be made from 2g of Nitrogen. I got 2.43g.

how can that be when there is 2 grams of nitrogen u cant make more then 2 grams can u ???

Reply 170

maxtate

Original post by hello my name is

how can that be it says 2 grams of nitrogen how can u make more then two grams :confused:

Basically that was 2 grams of nitrogen, ammonia is nitrogen and hydrogen... so answer was 2.43 :smile:

I accidentally rounded 2/28 in the first place (silly me) but working was all good so ill only lose 1 mark I hope, rest of exam was easyyy =P

Reply 171

MissGeek

Original post by khalidpatel

its been 6 hours and we ain got a bloody mark scheme up WOW c'mon guysssss

Do you remember what came up in question 2, I remember most of the questions, but I don't remember the order. If I can remember the question order, I will get an unofficial mark scheme up.

Reply 172

SlayerOfTheHero

Original post by SlayerOfTheHero

Questions I leave out have been answered (in my opinion) correctly in the quote.

How would the results be made more percise? (1)
Using measuring instruments with smaller scale divisions.

Calculate the mean average for these results? (2)
Can't remember values, I'm sure we all got this one.

Give to examples of experimental errors that could have been made? (2)
Weighing error on the balance (scale).
Gas escaping not into the cylinder but out of the trough.

What happens in the separator?
Ammonia is condensed into a liquid which flows out.
Unreacted nitrogen and hydrogen are fed back into first stage.

Why is stage 4 needed?
Not sure, think this was the pretext on the use of compound in manufacture of food, I would assume to check it is safe.

The manufacturers increase the pressure to (high number) why dont they go over this? (1)
High pressures are expensive to maintain, also are very dangerous.

Iron surface corrodes when exposed to air, this reduces its ability to conduct, explain why? (2)
Something to do with metal reacting with something in air which forms ionic compound which means electrons are fixed in lattice, reducing effectiveness of conductivity of charge.

If there is 20m of nitrogen how much hydrogen would you need?
how much ammonia could you make with 2g of nitrogen?
2/28 then 2/28 x 34 = 2.43

Why when pressure is increase does the amount of ammonia increase?
More moles of reactants than products.

What ion makes soluton acidic?
H+

Which ion make soltuion alkaline?
OH-

Why do the chloride ions go to the positive electrode?
Negatively charged chlorine moves to positively charged electrode.

That's what I've got, feel free to comment with any rebuttal you have as I could easily be wrong.

We answered some earlier if you bothered looking back at previous posts in the thread.

Reply 173

daniya12

Original post by kILLERm

the answer was 2.43g

yes thats what i got, i menat the relative atomic mass was 28

Reply 174

daniya12

Original post by hello my name is

how can that be when there is 2 grams of nitrogen u cant make more then 2 grams can u ???

no cos there was hydrogen too

Reply 175

daniya12

Original post by lfc_all_day

so far your looking like a high b/low a. it really depends on i the physics paper is hard/easy. generally speaking, marks for an a in the physics would be 26-30?

Reply 176

MissGeek

Hi guys,

I remember the majority of the questions, but can anyone remember the question order? If so, then please can you tell me, and I promise to get an unofficial mark scheme up :smile:

Thank You

Reply 177

Chlomc

I posted all of the questions i could remember on page 7, with some of the answers i knew and ayer of the hero answered some more. I have no idea what order they were in or how many marks were awarded to each answer though. But take a look as it may jog your memory