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edexcel IGCSE chemistry 1CR 2016

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Original post by ccchiulam
It's tricky !! Coz usually there must be a change in yield


Really? I don't think so, I think it's plausible for there to be no change in yield.
Original post by Igcse1student
What about the one that asked why does h2 have a low melting point?


That was so confusing! At first, it said that the bonds in H2 were strong, so I was wondering why H2 had a low melting point. I just made some stuff up about how very little energy is needed to overcome the weak bonds, hence there being a low boiling point. I probably didn't get any marks for that, though.
I'm just praying that the grade boundaries are low this year :frown:
Original post by Igcse1student
Mine was 0.3 something


Calculations answers for me :

0.384
1162 J( or something near to that)
160 KG(ammonia question)

Original post by Prudencejh
SAME!! I found it quite hard to! I felt like a lot of the questions were really different from previous years...


Me too. Tricky paper.

Original post by Igcse1student
I wrote it does escape, not sure about the reason though.


I wrote it doesn't escape because the volume of solution is very high. Not sure though.


Original post by Prudencejh
Also, did anyone think the exothermic graph was weird? I mean they drew an endothermic graph... I was so confused


Same here. Then realized I have to continue it.
Original post by nusquam
Okay guys, I remember some of the questions, so maybe share what you all wrote for each of them?

- Two reasons why putting the lid on the tank with the chromatography experiment in would help
- Solubility of sulphur dioxide in air and why
- Three reasons for cracking
- Which reactions for redox reactions
- Why burning C6H12S is bad


The one about chromotography I wrote: so no air can react with the solvents and so nothing can evaporate
Original post by nusquam
I'm just praying that the grade boundaries are low this year :frown:


That would be our only chance, what is your expected grade??
Original post by MohaimenH
Calculations answers for me :

0.384
1162 J( or something near to that)
160 KG(ammonia question)



Me too. Tricky paper.



I wrote it doesn't escape because the volume of solution is very high. Not sure though.




Same here. Then realized I have to continue it.


I DIDN'T CONTINUE THE GRAPH :angry:

I'm so annoyed at myself ><
Original post by nusquam
Okay guys, I remember some of the questions, so maybe share what you all wrote for each of them?

- Two reasons why putting the lid on the tank with the chromatography experiment in would help
- Solubility of sulphur dioxide in air and why
- Three reasons for cracking
- Which reactions for redox reactions
- Why burning C6H12S is bad


3 reasons of cracking: to make smaller more useful molecules that are in demand. I don't remember what else
Original post by Igcse1student
What did you guys write for the question about the bonding of cl2?


There is a shared pair of electrons which is attracted by the nuclei.

Original post by ccchiulam
It's tricky !! Coz usually there must be a change in yield


No. It isn't a must.

Original post by nusquam
Okay guys, I remember some of the questions, so maybe share what you all wrote for each of them?

- Two reasons why putting the lid on the tank with the chromatography experiment in would help
- Solubility of sulphur dioxide in air and why
- Three reasons for cracking
- Which reactions for redox reactions
- Why burning C6H12S is bad


- I wrote about solvent being flammable and volatile.
- air? It was solubility in solution,
- Smaller chain alkenes are more in demand as they're used as fuel and cracking produces alkenes which are used to make alchohols
- I wrote React 4 and 6 maybe.Not sure about correct answer tho.
-I wrote about it burning and forming SO2 which causes acid rain. Not sure about correct answer tho.
Reply 69
i said having the C6H12S in the crude oil is bad because it may be toxic and therefore give off poisonous gases, and it may also affect the polymerisation, as it is an impurity. It could also be extremely flammable and explode when combusted, which is dangerous as crude oil is fractioned to be a fuel.
Original post by Igcse1student
It's a paper for different regions in the world, different timings so no one cheats the system.


Thanks
Reply 71
Original post by Prudencejh
For the anomolous result I wrote because timer started too late...But I think it was wrong. What did you write?
For the inconsistent results I wrote due to higher temp, more kinetic energy so more sensitive to changes etc. But its definitely wrong I think...Not sure

I wrote the same thing, that she didn't start the timer on time
Original post by MohaimenH
There is a shared pair of electrons which is attracted by the nuclei.



No. It isn't a must.



- I wrote about solvent being flammable and volatile.
- air? It was solubility in solution,
- Smaller chain alkenes are more in demand as they're used as fuel and cracking produces alkenes which are used to make alchohols
- I wrote React 4 and 6 maybe.Not sure about correct answer tho.
-I wrote about it burning and forming SO2 which causes acid rain. Not sure about correct answer tho.


- Yeah, I did that too, I mentioned the lid being there as a safety precaution?
- Sorry, I meant to say solution. Anyway, did you write if it would stay in the flask or not?
- That's pretty much I wrote as well.
- I wrote reaction 3 and 4 >< I was really confused for this questions
- AHHH I completely forgot about that. For me, I just said that a smoky flame might be produced, and that the sulphur would be released, which is poisonous to humans. I forgot to mention that burning sulphur in oxygen forms sulphur dioxide :frown:
Original post by Igcse1student
That would be our only chance, what is your expected grade??


Our school did a mock exam at the beginning of the year, and my predicted grade was an A*. However, given the difficulty of this paper, I'm just aiming for an A/B. As long as I get around 70% I'll be happy.

What do you reckon you're going to get?
Reply 74
Original post by Igcse1student
Yeahss


YES
Original post by nusquam
- Yeah, I did that too, I mentioned the lid being there as a safety precaution?
- Sorry, I meant to say solution. Anyway, did you write if it would stay in the flask or not?
- That's pretty much I wrote as well.
- I wrote reaction 3 and 4 >< I was really confused for this questions
- AHHH I completely forgot about that. For me, I just said that a smoky flame might be produced, and that the sulphur would be released, which is poisonous to humans. I forgot to mention that burning sulphur in oxygen forms sulphur dioxide :frown:


Sorry. Mistype. I also wrote rxn 3 and 4.

I wrote it will stay in the flask because the volume of solution is enough to dissolbe jusy 0.384 g of the gas.
(edited 7 years ago)
Original post by MohaimenH
Sorry. Mistype. I also wrote rxn 3 and 4.

I wrote it will stay in the flash because the volume of solution is enough to dissolbe jusy 0.384 g of the gas.


I wrote that it will stay in the flask as well - however, I didn't really use the information since I didn't understand it, so I just ended up saying that the mass of sulphur dioxide was less than 100 (which is completely wrong, I know). Do you think I can get 1 mark from this?
Original post by nusquam
I wrote that it will stay in the flask as well - however, I didn't really use the information since I didn't understand it, so I just ended up saying that the mass of sulphur dioxide was less than 100 (which is completely wrong, I know). Do you think I can get 1 mark from this?


I really don't know. Sorry.

It depends on the examiner. He might decide to award a mark for the statement of correct answer (Yes/No). Or he might even reject your answer for the incorrect statement in the end.
Original post by theExtraNerd
Altho i knew everything about solubility but i messed that question up . due to shortage of time I started getting stressed up and began messing everything up. 😔
What was your answer for the mass of sulfur dioxide formed?
Mine was zero point something (can't recall properly)


0.384. What did you write for the mass produced of Ammonia?
Original post by PC.police
0.384. What did you write for the mass produced of Ammonia?


160kg

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