OCR Chemistry F321~ 23rd May 2014~ AS Chemistry

OP

If we forget to write the answer on the answer line will they award the marks?

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Reply 22

username1136417

what's everyone got in the PSA?

Reply 23

thedontom

I've run out of papers to do for this unit and for unit 2!
I'm confident for the exams, but I'm messing up the coursework...

Reply 24

amyyy163

Original post by Mutleybm1996

If we forget to write the answer on the answer line will they award the marks?

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I'm sure they would :smile:

Reply 25

amyyy163

Original post by gonnafail17

Completely dreading the exam, does anyone have any quick efficient ways of learning all that lone pair/ angles crap?

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Just keep reading over it... Best advice really. Or, copy them all out and stick them somewhere in your house where you spend a lot of time? I have a poster stuck to my bathroom door so that when I brush my teeth I read it. Simple but effective :smile:

Reply 26

OP

When assigning oxidation numbers to NaClO would Na or Cl take priority?

So O is -2

Na is +1 and Cl is -1 so which would i use to determine which is +3 or +1?

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Reply 27

mattcandy3

6

Na is a metal so it is always +1, (unless a transition metals, you meet them next year) oxygen is always -2, expect in some cases, so Cl will be +1 in this case.

Reply 28

OP

Original post by mattcandy3

Na is a metal so it is always +1, (unless a transition metals, you meet them next year) oxygen is always -2, expect in some cases, so Cl will be +1 in this case.

Thanks

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Reply 29

amyyy163

Original post by mattcandy3

Na is a metal so it is always +1, (unless a transition metals, you meet them next year) oxygen is always -2, expect in some cases, so Cl will be +1 in this case.

Why does the Na take priority? (sorry, I'm just interested haha :smile:

)

Reply 30

mattcandy3

6

it is not to do with the Na, (they just tell you this in as), it is more to do with the chlorine Chlorine Cl is -1 in many simple compounds combined with a less electronegative, however when combined with the more electronegative O or F, Cl has a (+) oxidation state of +1, so its not really, about the Na, more about the chlorine, and the effects of electronegative

Reply 31

WesterosWildling

3

My only problem is rushing hope I can get at least 48/49!

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Reply 32

bbadonde2

4

Original post by WesterosWildling

My only problem is rushing hope I can get at least 48/49!

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Aim higher! At least 53/54 I'm aiming for! The more UMS the better

Reply 33

OP

ImageUploadedByStudent Room1399069480.558025.jpg

Can someone help me understand this question please?

Ignore the circling!

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Reply 34

a123a

14

Original post by Mutleybm1996

Can someone help me understand this question please?

Ignore the circling!

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Al has 3 electrons in its outershell so the first one will be in the p orbital. (Draw it to visualise it easily)
so 2 and 3 are in the s sub shell. Then you have to go another 6 to get to the next s sub shell which will be 10 and so 11

Reply 35

MarkAntoine

Anyone got any predictions as to what topics will be tested?

Reply 36

toonervoustotalk

20

Original post by MarkAntoine

Anyone got any predictions as to what topics will be tested?

Defo ionisation energies
Dot and cross
Group 7
And moles
That is what i think

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Reply 37

theworld

Original post by Mutleybm1996

Can someone help me understand this question please?

Ignore the circling!

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You have to work backwards.

1s2 2s2 2p6 3s2 3p1

Its asking for where electrons from s sub shells are lost. So start from the end... 3p1.. no.. 3s2.. yes 3s1.. yes << so thats 2nd and third.. then 2p1.. no 2p2.. no 2p3.. no 2p4.. no 2p5.. no 2p6.. no 2s2.. yes 2s1.. yes << so thats 10 and 11th.

Btw I got an E on my first time and B on this test second time.. its easy!

(edited 9 years ago)

Reply 38

OP