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National 5 Chemistry

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If you guys need any last minute calculation or question help tag me in, been awhile since nat 5 but i'll see what I can do :smile:
Original post by Zain-A
If you guys need any last minute calculation or question help tag me in, been awhile since nat 5 but i'll see what I can do :smile:


Thanks, that would be great.

I was looking through this National 5 Question book and it asked me a question about a process or something called "Crackling". I am certain I wasn't taught that in chemistry this year, Did you know anything or did you need to know anything about it when you were in nat 5 ?
Original post by Ethan100
Thanks, that would be great.

I was looking through this National 5 Question book and it asked me a question about a process or something called "Crackling". I am certain I wasn't taught that in chemistry this year, Did you know anything or did you need to know anything about it when you were in nat 5 ?


The only thing I could think you are talking about is Cat. Cracking. Other than that I have never heard of crackling. Could you post the question either way and I will take a look?
Original post by Zain-A
The only thing I could think you are talking about is Cat. Cracking. Other than that I have never heard of crackling. Could you post the question either way and I will take a look?


Ooooooops, I might of read it wrong the first time... It is cracking, my bad :P
Original post by Ethan100
Ooooooops, I might of read it wrong the first time... It is cracking, my bad :P


No problem, you gave everyone a bit of a scare haha
Original post by Zain-A
No problem, you gave everyone a bit of a scare haha


hahaha, Yeah I'm really sorry :P
I understand titration questions but I just don't understand some calculations questions...
Reply 67
Original post by SocialStudiesETC
I understand titration questions but I just don't understand some calculations questions...


What ones?

Specific heat capacity? Mole calculations?
Mole calculations :frown:
Reply 69
Original post by SocialStudiesETC
Mole calculations :frown:


What is it that you don't get?

n=cv or n=m/gfm

Or both?
Both, like I never know when to use which one and then some questions just do not make sense to me at all
Does anybody know if there is a chance that a PCV calculation could come up?? Thanks


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Reply 72
Original post by SocialStudiesETC
Both, like I never know when to use which one and then some questions just do not make sense to me at all


PM me the questions you get stuck on. I can help you :smile:

Original post by Abbyy1234
Does anybody know if there is a chance that a PCV calculation could come up?? Thanks


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What do u mean by PCV?
Original post by Ethan100
Thanks, that would be great.

I was looking through this National 5 Question book and it asked me a question about a process or something called "Crackling". I am certain I wasn't taught that in chemistry this year, Did you know anything or did you need to know anything about it when you were in nat 5 ?


Cracking i really breaking down a long chained hydrocarbon into smaller ones. You need to know it breaks it down into an alkene and alkane. If they ask you what one it is just count the number of hydrocarbons until you get the correct number (if that makes sense).
Original post by Jay431
PM me the questions you get stuck on. I can help you :smile:


What do u mean by PCV?


Titration questions probably

P - number of Hydrogens
V - Volume of solution
C - Concentration

PVC = PVC
substitute in
rearrange to find missing value
Jay, I just realised I'm not struggling with mole calculations haha. It's calculations from equations apparently!
Original post by SocialStudiesETC
Both, like I never know when to use which one and then some questions just do not make sense to me at all


For mole calculations they may want you to find out the mass of one and give the concentration of another thing. You must find the number of moles (n) to do this as it links both calculations. It's hard to go over here but I'm sure if you ask your teacher to go over it with you. Really what I am saying it find the number of moles of the thing you are given using te right formula ie. if they talk about concentration do n=cxv then use that do do what they ask (hoped that helped):smile:
Original post by studyranger
For mole calculations they may want you to find out the mass of one and give the concentration of another thing. You must find the number of moles (n) to do this as it links both calculations. It's hard to go over here but I'm sure if you ask your teacher to go over it with you. Really what I am saying it find the number of moles of the thing you are given using te right formula ie. if they talk about concentration do n=cxv then use that do do what they ask (hoped that helped):smile:


Thank you, but I just realised it's calculations from equations I struggle with! I'm not too sure on them.
Reply 78
Original post by Abbyy1234
Does anybody know if there is a chance that a PCV calculation could come up?? Thanks


Posted from TSR Mobile


Original post by SocialStudiesETC
Titration questions probably

P - number of Hydrogens
V - Volume of solution
C - Concentration

PVC = PVC
substitute in
rearrange to find missing value


Oh well in that case, yes. They always have a titration question.

I don't use PVC lol.

Original post by SocialStudiesETC
Jay, I just realised I'm not struggling with mole calculations haha. It's calculations from equations apparently!


Oh I understand now.

Give us an example and I'll show you what to do.
Original post by Abbyy1234
Does anybody know if there is a chance that a PCV calculation could come up?? Thanks


Posted from TSR Mobile


Do you mean concetration calcualtions?
In our school we got taught NCV...
(edited 7 years ago)

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