Year 12s: what will be the first way you research your future options? >>

WJEC - AS Chemistry Unit 1 [New Spec] 27th May 2016

Scroll to see replies

Did anyone manage to get an answer to the fluoride ions in water calculation? Probably the hardest chemical calculation I've ever seen on WJEC

Yeah I got an answer of 0.7 something... Have no clue if it's correct, but it wasn't actually worth that many marks.

Reply 21

burninginneon

Original post by Elliottmanwaring

I must say- I revised the most for Chemistry so I didn't find it toooo bad but it was a very long peper, I think I was the only one to finish the whole paper.. What % did everyone get as the % of Was it Si in the compount which was like 11.42g or something?

I didn't know how to do that question... I kept coming out with an answer like 0.001% and I'm not really sure where I messed up because I spent about 20 minutes going back over it. It must've just been my method or I misunderstood the question

Reply 22

robinback

Original post by RasputinReborn

No, that wasn't Si, that was NaI and NaCl

Si Ar was 21 something

For the % thing for Na I had 40 something (not sure about this)

Posted from TSR Mobile

I got something like 40% as well, no idea how mind you haha

Reply 23

burninginneon

Original post by RasputinReborn

3 marks is quite a fair bit

Posted from TSR Mobile

Was it worth three marks? Must be confusing the amount of marks for another question then. The H-Cl bond strength question was only worth 2 marks and that required about 4 different calculations, which was pretty annoying.

Reply 24

burninginneon

Original post by RasputinReborn

Yeah, I absolutely cocked that up because I was running out of time. It seemed like an easy calculation as well.

Posted from TSR Mobile

It was once you knew what to do. Everyone I spoke to didn't get it because of the fact it told them to use the data booklet and they thought it was instrumental analysis, which isn't even in this unit (apart from mass spectrum)

Reply 25

Emskibump

Original post by RasputinReborn

Thank Christ. Thought I did that wrong. It's unlikely that we're both wrong I suppose.

Posted from TSR Mobile

I got 48%

Posted from TSR Mobile

Reply 26

username2459953

Original post by robinback

I got 2 too :smile:

I decided to throw a 2 on the answer line after giving up on the calculations, so hopefully got a mark there without all the calculations :wink:

Reply 27

gwen11ian

Original post by Emskibump

I got 2, what did you get?

Posted from TSR Mobile

yep I got 2 tooo!!!

Reply 28

burninginneon

Original post by RasputinReborn

Did you have to find the frequency than plug it into E=hf then multiply by Avogadro constant?

Posted from TSR Mobile

Yep! So not too bad

Reply 29

fanwarrior123

Original post by RasputinReborn

Did anyone get a 1.2 pH for one of the calculation questions?

yes!!!! i did :biggrin:

Reply 30

Lil670

What did you get when comparing the melting points, after the drawing the hydrogen bonding diagram part, was it to do with one having hydrogen bonding and the other not? :/

Reply 31

robinback

Original post by Lil670

What did you get when comparing the melting points, after the drawing the hydrogen bonding diagram part, was it to do with one having hydrogen bonding and the other not? :/

That's what I put, just a hopeful guess

Reply 32

Elliottmanwaring

Original post by RasputinReborn

Both of them could hydrogen bond...

Posted from TSR Mobile

Yeah they could bith hydrogen bond. One had NH3 and the other had an OH and I said the OH had a more electronegative O therefore the electronegativity difference In the hydrogen bond was greater therefore the strength of the bond would increase. In addition, one ofthe molecules was slightly larger than the other so there was a greater surface area for contact between molecules therefore there could be induced diploe induced dipole interactions. Kinda waffled a load of stuff I know about bonding tbh...

Reply 33

ambarellarose

That exam is a blur to me now. Do you think the boundaries will be lowered? whats the usual grade boundaries? and did anyone do biology yesterday? :smile:

Reply 34

ChemSinceDaay...

I got x=2 but let's just say overall that paper was hell!!!

Reply 35

username2459953

Original post by ambarellarose

That exam is a blur to me now. Do you think the boundaries will be lowered? whats the usual grade boundaries? and did anyone do biology yesterday? :smile:

Good to see you on this thread too haha :tongue:

Reply 36

ChemSinceDaay...

What did u guys get for atom economy? I got 77.0%

Reply 37

ChemSinceDaay...

Original post by Emskibump

I got 2, what did you get?
Posted from TSR Mobile

I got X=2 and so did most people

Reply 38

Chemistrycat98

What was with the electrolysis question, wasn't even on the spec...

Reply 39

Elliottmanwaring

Original post by Chemistrycat98

What was with the electrolysis question, wasn't even on the spec...

It was on the spec, iodide ions gain electrons forming iodine which turns to a red/brown solution. Then you'd explain why- basically liberation of Iodine but I cba to explain now.. Go on chemguide and it'll explain probably.