EdExcel Further Additional Chemistry (Triple) C3 Exam Wednesday 17th June 2015

Guys for o.2 maths q i wrote the wrong answer but my working was right i made a error in conversion form g dm-3 to mold m-3 will i get 2/3 ?

Also what did u guys write for the qs about test for hard water?

Did you get 220 as the answer and forget to convert?

Reply 61

tahmidtahmid32

conditions for production of ethanol from ethene?? 2 conditions?

Reply 62

Pure class

9

Original post by tahmidtahmid32

conditions for production of ethanol from ethene?? 2 conditions?

water (steam)
high temp?

Reply 63

Funku

Original post by Pure class

water (steam)
high temp?

I wrote about needing a catalyst as well.

Reply 64

ceremonials

9

I put water in excess and high temperature but they were complete guesses

I got confused about the catalyst because I knew the dehydration of ethanol to ethylene needed catalyst but

Reply 65

RhysH98

2

I actually loves this test the two 6 mark questions were an absolute gift so much to write on them. K my one I think i got wrong was the affect of pressure on the rage of attaining the equilibrium. But overall think of got roughly 55. So happy.

Reply 66

gcses2015

2

Guys what did you write for the first 6 marker? I wrote so much ****. I said that hard water is caused by calcium and magnesium ions. I said soft water contains sodium ions. Soft water can be identified as it forms easily a lather with soap. Also sodium ions can be identified by flame test. It gives out a yellow flame. Then i talked about temporary hard water, I wrote the equation where calciun hydrogencarbonate decomposes to producs caco3 and co2. I said it can be softened by boiling. Then i said it forms scum and it doesnt easily form lather with soap. Then I talked about how Co2 gas can be identified as it is present in temporary hard water. Then I went on talking about hard water which is caused by insoluble calcium sulfate and I described the test to identify sulfate ions. Also I said they form scum. I m so worried that I messed this question up. How many marks do you think I will get? :/

Reply 67

RhysH98

2

Original post by gcses2015

Guys what did you write for the first 6 marker? I wrote so much ****. I said that hard water is caused by calcium and magnesium ions. I said soft water contains sodium ions. Soft water can be identified as it forms easily a lather with soap. Also sodium ions can be identified by flame test. It gives out a yellow flame. Then i talked about temporary hard water, I wrote the equation where calcium hydrogencarbonate decomposes to producs caco3 and co2. I said it can be softened by boiling. Then i said it forms scum and it doesnt easily form lather with soap. Then I talked about how Co2 gas can be identified as it is present in temporary hard water. Then I went on talking about hard water which is caused by insoluble calcium sulfate and I described the test to identify sulfate ions. Also I said they form scum. I m so worried that I messed this question up. How many marks do you think I will get? :/

I put calcium hydrogencarbonate causes temporary hard water and calcium carbonate causes permenant hard water. Then first mix all sample with soap to find the soft water that forms a lather. The heat the other two as only temporary hard water can be softened by heating as the calcium hydrogencarbonate thermally decomposes to produce calcium carbonate carbon dioxide and water. Therefore the solution that produces a solid is the temporary hard water leaving the other to 've the permanent hard water.

(edited 8 years ago)

Reply 68

engca

5

What was the answer for how do you transfer the alkali? Pipette?

Reply 69

DanG12345

4

Could someone please make an unofficial mark scheme?? :smile:

Reply 70

gcses2015

2

Original post by RhysH98

I put calcium hydrogencarbonate causes temporary hard water and calcium carbonate causes permenant hard water. Then first mix all sample with soap to find the soft water that forms a lather. The heat the other two as only temporary hard water can be softened by heating as the calcium hydrogencarbonate thermally decomposes to produce calcium carbonate carbon dioxide and water. Therefore the solution that produces a solid is the temporary hard water leaving the other to 've the permanent hard water.

Yeah same. How many marks do you think I would have got? I m so worried. :/

Reply 71

gcses2015

2

Original post by engca

What was the answer for how do you transfer the alkali? Pipette?

Yeah.

Reply 72

KD1024

OP

2

Original post by RhysH98

I put calcium hydrogencarbonate causes temporary hard water and calcium carbonate causes permenant hard water. Then first mix all sample with soap to find the soft water that forms a lather. The heat the other two as only temporary hard water can be softened by heating as the calcium hydrogencarbonate thermally decomposes to produce calcium carbonate carbon dioxide and water. Therefore the solution that produces a solid is the temporary hard water leaving the other to 've the permanent hard water.

I put exactly that but at the end tested the boiled solutions again with soap to see which makes lather and the one left is perm hard

Reply 73

KD1024

OP

2

Original post by CosimaNiehaus

Could someone please make an unofficial mark scheme?? :smile:

Don't think anyone would bother as P3 on Friday

Reply 74

green8

9

I got 0.2 for concentration question. For one about titration where they gavemultiple choice i chose 25.10 - not sure if thats right. For the one about the measuring out alkali for a titration i said that you cab use a pipette to suck up the alkaili but really wasnt sure.
I thought it was much harder than past papers ive done.

Reply 75

gcses2015

2

Original post by green8

I got 0.2 for concentration question. For one about titration where they gavemultiple choice i chose 25.10 - not sure if thats right. For the one about the measuring out alkali for a titration i said that you cab use a pipette to suck up the alkaili but really wasnt sure.
I thought it was much harder than past papers ive done.

Same, I got exactly the same answers you got.

Reply 76

Katherines01

7

Original post by green8

I got 0.2 for concentration question. For one about titration where they gavemultiple choice i chose 25.10 - not sure if thats right. For the one about the measuring out alkali for a titration i said that you cab use a pipette to suck up the alkaili but really wasnt sure.
I thought it was much harder than past papers ive done.

I explained you'd use a pipette but the fact it was 2 marks really threw me? like it needed something else as well but no idea what else you could write...
and I also got 25.10 I think! and yeah I found it pretty hard tbh

Reply 77

gcses2015

2

Original post by Katherines01

I explained you'd use a pipette but the fact it was 2 marks really threw me? like it needed something else as well but no idea what else you could write...
and I also got 25.10 I think! and yeah I found it pretty hard tbh

Yeah i was a bit confused why it was 2 marks so I just said pipette measures the alkali accyrately to get the second mark. Hooe it's right. What did you write for the equilibrium attainment question?

Reply 78

smwsammy98

Original post by gcses2015

Yeah i was a bit confused why it was 2 marks so I just said pipette measures the alkali accyrately to get the second mark. Hooe it's right. What did you write for the equilibrium attainment question?

That confused me too, i wrote use a pipette and then wrote about using a burette too. Loads of people said they found it hard but i liked the 6 markers