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# Edexcel IAL WCH04 ~ 13th Jan 2014 ~ Unit 4 watch

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1. (Original post by examman123)
It was the surrounding entropy change and total entropy change..

When temperature is increased obviously surrounding entropy change will decrease (because entropy change of surrounding = -deltaH/T)
Since total entropy change = entropy change of surrounding + entropy change of system.. the value for total entropy change will decrease as well..
however, the reaction will undergo completion as it's an exothermic reaction (so, despite what temperature the surrounding is positive) and the entropy change of system is also positive as disorderedness increases as products are formed...
So what would be the effect of increasing temp on the extent of the rectn ?

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2. (Original post by kcapsoccer)
do you remember how many marks did that question have?

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I have no idea..

(Original post by TheKingOfTSR)
So what would be the effect of increasing temp on the extent of the rectn ?

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That I am not sure that part.. :/
I was hoping it was a reversible reaction, however it wasn't :|
3. (Original post by TheKingOfTSR)
So what would be the effect of increasing temp on the extent of the rectn ?

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I remember my teacher saying extent of reaction refers to entropy, so when temp. is increased surrounding entropy decreases as it is inversely proportional, therefore total entropy also decreases. (Becomes less positive). This means extent of reaction decreases.
That is what I wrote anyway...

How did you find the paper and what do you think will be A? (Out of 90?)

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4. (Original post by Relaxedexams)
I remember my teacher saying extent of reaction refers to entropy, so when temp. is increased surrounding entropy decreases as it is inversely proportional, therefore total entropy also decreases. (Becomes less positive). This means extent of reaction decreases.
That is what I wrote anyway...

How did you find the paper and what do you think will be A? (Out of 90?)

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But if the reaction is not reversible then there wouldn't be any extent involved right. It would either be completion or no reaction ? :/

The paper IMO wasn't much different from previous papers. I would expect a* to be at around 80 or little less and a to lie on about 70. 120 ums at 85/86? lol
5. (Original post by TheKingOfTSR)
But if the reaction is not reversible then there wouldn't be any extent involved right. It would either be completion or no reaction ? :/

The paper IMO wasn't much different from previous papers. I would expect a* to be at around 80 or little less and a to lie on about 70. 120 ums at 85/86? lol
In this question I think extent refers to how spontaneous it is. I dunno what else it could mean in a nonreversible reaction...

I too found the paper similar to previous years, but made some stupid mistakes...the main of which was not going through the data booklet beforehand. Lost about 5-10 mts trying to find entropy of CO2...subsequently I was hard on time

And for the lnk graph, I started the y axis from -2 to -14 from down...that is not even possible, so I had a positive gradient...found the mistake but didn't have time . Anyway I marked the axis, found m and found Ea. Do you think I'll get marks for plotting the points for my graph?

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6. (Original post by Relaxedexams)
In this question I think extent refers to how spontaneous it is. I dunno what else it could mean in a nonreversible reaction...

I too found the paper similar to previous years, but made some stupid mistakes...the main of which was not going through the data booklet beforehand. Lost about 5-10 mts trying to find entropy of CO2...subsequently I was hard on time

And for the lnk graph, I started the y axis from -2 to -14 from down...that is not even possible, so I had a positive gradient...found the mistake but didn't have time . Anyway I marked the axis, found m and found Ea. Do you think I'll get marks for plotting the points for my graph?

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Yeah. :/

I think you'll get marks plotting the points correctly according to your graph. You might loose only 1 mark; that's for wrong/bad choice of scale/axis. But I think drawing like that was would still be no problem provided that you calculate the gradient carefully, ensuring that the signs are correct.

But did you get a positive value for the gradient??
Even though you had a positive gradient line, if you correctly use (y2-y1)/(x2-x1), you would have a negative value right?

If you did get a negative value for EA , then the final mark would be lost.
7. (Original post by TheKingOfTSR)
Yeah. :/

I think you'll get marks plotting the points correctly according to your graph. You might loose only 1 mark; that's for wrong/bad choice of scale/axis. But I think drawing like that was would still be no problem provided that you calculate the gradient carefully, ensuring that the signs are correct.

But did you get a positive value for the gradient??
Even though you had a positive gradient line, if you correctly use (y2-y1)/(x2-x1), you would have a negative value right?

If you did get a negative value for EA , then the final mark would be lost.
I did get a positive gradient, but I put Ea as positive
Just put in a negative gradient.

What was Ea btw? I got 9970 or something...
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8. (Original post by Relaxedexams)
I did get a positive gradient, but I put Ea as positive
Just put in a negative gradient.

What was Ea btw? I got 9970 or something...
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haha

I forgot what i got..
9. (Original post by Relaxedexams)
I did get a positive gradient, but I put Ea as positive
Just put in a negative gradient.

What was Ea btw? I got 9970 or something...
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Didnt the question ask to give to 3 significant figures?
I think I got 102kJ... my initial Joule answer divided by 1000..
10. (Original post by examman123)
Didnt the question ask to give to 3 significant figures?
I think I got 102kJ... my initial Joule answer divided by 1000..

Yeah I also got 120kJ.
11. hi guys did anyone do unit 6 today? If yes how did you find the paper? :/
12. (Original post by kcapsoccer)
hi guys did anyone do unit 6 today? If yes how did you find the paper? :/
It was weird .. How about you??

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13. (Original post by Conaura)
It was weird .. How about you??

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yep i also think it was pretty wierd.. and i think i did some silly mistakes.. :/

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14. (Original post by kcapsoccer)
yep i also think it was pretty wierd.. and i think i did some silly mistakes.. :/

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Hello ppl how do find this new iAL as compared to gce??? Was the new one harder or easier than the old one??
15. (Original post by Just ZK)
Hello ppl how do find this new iAL as compared to gce??? Was the new one harder or easier than the old one??
No difference, I would say.
Chemistry was exactly the same style and difficulty as previous papers. I did the unit 4 papers of biology chemistry and physics.

Physics... Was IMO easier than the last two papers. But there were some few tough questions.

But on the other hand, the biology paper was very much different from the previous papers... In the sense that the style of questions were the same.. The difficulty of the questions was not much different... But the content was urgh... It wasn't a unit 4 paper at all. Rather it was a unit 1,2,4 paper. Extremely synoptic.

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16. The 13th Unit (2014) Oryginał Online

http://efilmy-online.pl/2014/03/09/t...2014-oryginal/
17. do you guys know where the unit 6 thread is?

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