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# AS Chemistry- helping each other out! watch

1. (Original post by Shazzyroxz96)
http://s11.postimg.org/980xvhyv7/table.jpg
The Ans is A......
First write out the reaction, and balance it.

Find the molar ratios of NaCl to NaOH, H2 and Cl2.

You must make sure to have NaCl = 1 mol, since we're told that 58.5 kg of it is electrolysed, so do that and you'll end up with a new molar ratio.

Find the molar mass of the products and multiply this by the " new " molar ratio.

If you did everything correctly, you should end up with A as your answer. If not, I'd be happy to break it down further ^_^

Hope that helped!
2. (Original post by Shazzyroxz96)
Help please........ the ans is B

Which of these equations represents the reaction of sulphur dioxide with an excess of aqueous

sodium hydroxide?

A SO2 + NaOH ----> NaHSO3

B SO2 + 2NaOH -------> Na2SO3 + H2O

C SO2 + 2NaOH ------> Na2SO4 + H2O

D SO2 + 2NaOH -----> Na2SO4 + H2
The keyword here is "excess". This should let you know that NaOH has to be the greater quantity, so you can eliminate Option A.

From B,C and D, break the reactants up into ions and see if you can arrange them to make the mentioned products.

SO2 --> S2+ and O2-
2NaOH --> 2Na+ and 2OH-

Hope that helps!
3. for this years chemistry as level exams what ums and grade would i be expecting if i got:

f321: around 46 marks
f332: 74ish
and full ums in coursework 40marks

much appreciated
4. (Original post by Skygon)
First write out the reaction, and balance it.

Find the molar ratios of NaCl to NaOH, H2 and Cl2.

You must make sure to have NaCl = 1 mol, since we're told that 58.5 kg of it is electrolysed, so do that and you'll end up with a new molar ratio.

Find the molar mass of the products and multiply this by the " new " molar ratio.

If you did everything correctly, you should end up with A as your answer. If not, I'd be happy to break it down further ^_^

Hope that helped!
If you dont mind can you please detail it to me? Thanks in Advance
5. (Original post by Shazzyroxz96)
If you dont mind can you please detail it to me? Thanks in Advance
6. Question 33, help please....... i dont understand statement 3
Ans is C,
7. (Original post by C0balt)
Thank you so so much It was very comprehensible
http://postimg.org/image/8giq0huc9/full/
Ans is A
9. (Original post by Shazzyroxz96)
Question 33, help please....... i dont understand statement 3
Ans is C,
Tricky to explain, but when dissociation occurs there are "two" molecules of gas present per pcl5 within the sryinge. When dissociation does not occur there is only "one" molecule of gas in the syringe
Hence, there is less gas when dissociation does not occur
10. http://onlineexamhelp.com/wp-content..._s14_qp_11.pdf
Question 3.......Help please!!!!!!!! The Ans is D
My doubt is why cant the answer be C????
11. (Original post by Shazzyroxz96)
http://onlineexamhelp.com/wp-content..._s14_qp_11.pdf
Question 3.......Help please!!!!!!!! The Ans is D
My doubt is why cant the answer be C????
The definition of enthalpy of formation is enthalpy change when a mole of compound is formed from its elements in standard states under standard condition. Therefore the arrow is pointing the right direction (from elements to compound), which means you do not have to change the direction of arrow by changing the sign

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12. Is anybody aware of an unofficial EMPA mark scheme??
13. Exam board AQA
As-level....
Referring to above comment
14. how did everyone find f324?
15. Hi guys, I am a mature student and I intend to apply for a course in A-level Chemistry. I have a question regarding the exam boards- which one is the easiest for Chemistry from AQA, Edexcel and OCR?
16. (Original post by karzen)
Hi guys, I am a mature student and I intend to apply for a course in A-level Chemistry. I have a question regarding the exam boards- which one is the easiest for Chemistry from AQA, Edexcel and OCR?
There's two in OCR, you have OCR a and OCR b it's sorta hard to tell which is easiest especially as there's now the a level reform so some of the specifications are changing slightly.

I do OCR a and really enjoy the course but exams this year really turned the tables
I am sure others that do the other exam boards will provide an insight into their chem exam board good luck

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17. (Original post by KeilahDeere)
There's two in OCR, you have OCR a and OCR b it's sorta hard to tell which is easiest especially as there's now the a level reform so some of the specifications are changing slightly.

I do OCR a and really enjoy the course but exams this year really turned the tables
I am sure others that do the other exam boards will provide an insight into their chem exam board good luck

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Thanks anyways! I am actually going to do a fast track as I am a foreigner and hold an equivalent of A-levels so I know the material. My question is more about marking schemes of each board- I don't really want to get into a board that is super tricky with their questions and overly strict with marking. As of now I am really confused because some people say Edexcel is the hardest and then other say it's the easiest and the same goes for OCR. I've heard OCR's exams are super hard and so are their marking schemes.
18. (Original post by karzen)
Hi guys, I am a mature student and I intend to apply for a course in A-level Chemistry. I have a question regarding the exam boards- which one is the easiest for Chemistry from AQA, Edexcel and OCR?
I'd say AQA definitely. This is because if you do all the past papers online you will get a just of the mark scheme wording and they tend to repeat questions pretty much all of the time
19. (Original post by Bhavika22)
I'd say AQA definitely. This is because if you do all the past papers online you will get a just of the mark scheme wording and they tend to repeat questions pretty much all of the time
Thanks! And do you happen to know anything about Edexcel? What about their marking schemes? I've heard they are very straight forward with their questions, which is definetely a huge pro!
20. (Original post by karzen)
Thanks! And do you happen to know anything about Edexcel? What about their marking schemes? I've heard they are very straight forward with their questions, which is definetely a huge pro!
I'm not sure about edexcel. But I absolutely loved aqa chemistry. The past papers help a lot!

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