Ocr f321 23 may 2013~official discussion thread

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

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Ferrari_1996

For last question

Li: Between delocalised electrons and positive ions
Carbon: Between carbon atoms in structure
Flourine: Between flourine molecules as its van der waals forces

Oh I got no marks for the last row then. For the 2nd row was it giant for the one in the middle and covalent for the one on the right?

Reply 681

MathsNerd1

Original post by Dr. Django

van der waals i put

Same here but wouldn't it be dipoles as phosphorus is more electronegative than hydrogen?

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Reply 682

Ferrari_1996

Original post by Dr. Django

van der waals i put

For the other one it was Hydrogen Bonding wasn't it?

Reply 683

General SMG

Main forces in NH3 was Hydrogen bonds and main force in PH3 was Van Der Waals :redface:

Reply 684

Dr. Django

Original post by MathsNerd1

But it wasn't that hard, at all, if you looked into the book a few times you should've been fine, the most challenging was the last part of the last question.

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It wasnt hard I agree, i found it decent! Not sure about the last being the most challenging though, I reckon the bond angles would have thrown quite a few people

Reply 685

gogo122

Original post by Ferrari_1996

For the other one it was Hydrogen Bonding wasn't it?

Yes NH3 was Hydrogen bond and PH3 one was Van der waals'

Reply 686

KatiexZoe

What did people write for the 5 marker on reactivity of group 2 with chlorine?

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Reply 687

Dr. Django

Original post by MathsNerd1

Same here but wouldn't it be dipoles as phosphorus is more electronegative than hydrogen?

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true, hopefully VDW is ok! its non polar anyway

Reply 688

MathsNerd1

Original post by Dr. Django

It wasnt hard I agree, i found it decent! Not sure about the last being the most challenging though, I reckon the bond angles would have thrown quite a few people

I suppose but the wording was quite weird and yeah, that shouldn't have caused an issue but I assume it will with the rest of my group that sat it.

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Reply 689

kelvinbeyioku

Original post by Dr. Django

van der waals i put

i thought that it was a permanent dipole-dipole?

Reply 690

MathsNerd1

Original post by Dr. Django

true, hopefully VDW is ok! its non polar anyway

Well I hope that it could be both as I crossed it out to put the dipoles :-/ I doubted myself and how would it be non polar if there is the electronegative differences?

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Reply 691

flyhigh99

Guys this test wasn't hard at all?

what was the highest grade boundaries we ever had?

Reply 692

Dr. Django

Original post by kelvinbeyioku

i thought that it was a permanent dipole-dipole?

It could be im unsure

Reply 693

TheFootyKing19

Original post by flyhigh99

Guys this test wasn't hard at all?

what was the highest grade boundaries we ever had?

Last May. It was 50/60 to get an A!

Reply 694

yodawg321

Original post by MathsNerd1

Same here but wouldn't it be dipoles as phosphorus is more electronegative than hydrogen?

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I put in permement dipole to dipole attractions for that. Not van der waals

Reply 695

Dr. Django

Original post by flyhigh99

Guys this test wasn't hard at all?

what was the highest grade boundaries we ever had?

52 in Jan 2010, but that one was insanely simple; this will be more like 50 i would have thought

Reply 696

MathsNerd1

Original post by yodawg321

I put in permement dipole to dipole attractions for that. Not van der waals

Same here! As the lone pair of electrons would make it a polar substance.

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Reply 697

yodawg321

Original post by Ferrari_1996

Oh I got no marks for the last row then. For the 2nd row was it giant for the one in the middle and covalent for the one on the right?

Yeah I got giant and covalent.

I might be wrong though!

Reply 698

kelvinbeyioku

Original post by yodawg321

Yeah I got giant and covalent.

I might be wrong though!

i got the same :biggrin:

Reply 699

yodawg321

Original post by MathsNerd1

Same here! As the lone pair of electrons would make it a polar substance.

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Surely it will be VDW forces if it was non polar ? For example H2.
But both the molecules had different electronegativies so it will be perm dipole to dipole attractions?