Edexcel - Chemistry Unit 2 - 4 June 2013

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what topic does everyone find the hardest?

i dont like deciding which intermolecular force is dominating in a particular molecule. i also hate green chemistry, and the periodic table chapter (2 and 7)

Reply 281

Gnome :)

Original post by SKK94

In QWC (*) questions are we allowed to write in bullet points?

I think they usually expect continuous prose.

Reply 282

SKK94

Original post by Gnome :)

I think they usually expect continuous prose.

Oh ok. :/
Does the same apply to other subjects too?

Reply 283

Baraf

Original post by HarryMWilliams

The George Facer book has far too much information on in relation to the specification - if it isn't in the spec, then by all means read over it and get a general idea, but dont prioritise it over explicitly mentioned material.

will do, tnx.

I hope i finnish by friday so I can focus on my PHy and M2 exam :frown:

never ending revision

Reply 284

Gnome :)

Original post by SKK94

Oh ok. :/
Does the same apply to other subjects too?

I believe it does for the QWC questions at least.

However, you don't normally get more than 1 mark for QWC per question with an asterisk, so it's up to you- if you feel you'll have more time and pick up more content marks by using bullet points, they'll still mark it

Reply 285

SKK94

Original post by Gnome :)

Thanks. I just wanted to make sure. :smile:

Reply 286

jojo1616

Why 1-iodobutane has a higher
Boiling temp. than 1-chlorobutane? I thought C-I bond is weaker which means lower boiling temp..am i using the wrong concept?
Posted from TSR Mobile

Reply 287

username969261

Original post by jojo1616

Why 1-iodobutane has a higher
Boiling temp. than 1-chlorobutane? I thought C-I bond is weaker which means lower boiling temp..am i using the wrong concept?
Posted from TSR Mobile

The C-I bond is weaker, so you are right on that, but you are thinking of the bond strength, this bond doesnt break when they are boiled. You have to think about inter molecular forces. Because when you boil something you are separating the molecules, not the atoms in the molecules.

London forces, Permanent dipoles and Hydrogen bonds.

Reply 288

zyxwvuts

Can someone draw out the Sn2 reaction for water and a halogenoalkane for me? I'm a bit confused on charge x_x Thanks

Reply 289

posthumus

Original post by jojo1616

Why 1-iodobutane has a higher
Boiling temp. than 1-chlorobutane? I thought C-I bond is weaker which means lower boiling temp..am i using the wrong concept?
Posted from TSR Mobile

I think beaver_tron has corrected you on your misconception of factors that effect boiling temperature.

But forgot to add...
Iodine has more electrons therefore greater London forces :smile:

Reply 290

phaseshift

Original post by SKK94

LiAlH4, in dry ether.

Yah. People seem to forget the "in dry ether" bit at my Sixth Form.

Reply 291

wbrian

Original post by Gnome :)

Can you be a little more specific please? Any particular calculations you're stuck with? :smile:

yeah like titration ones and mols :frown:

Reply 292

Gnome :)

Original post by wbrian

yeah like titration ones and mols :frown:

If you post a question, with your working and what you're struggling with, I'll try and help you :smile:

Reply 293

Jayqwe

Anyone know how to do this question?

Propanal, CH3CH2CHO, and propanone, CH3COCH3, are isomers, but only propanal has
a significant peak in its mass spectrum at mass/charge ratio
A 15
B 29
C 43
D 58

With B being the answer