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Edexcel Chemistry A2 Unit 5 ~ Wednesday 19th June 2013 (Now Closed)

Reply 2220

Qwob

1

Original post by mrhedgehog

Im pretty sure that when butylamine and sulfuric acid react the same is (ch3ch2ch2ch2nh3)2 ^2+ So4^2-

I put that, maybe they'll accept both...

Reply 2221

Bello08

Original post by Qwob

I said that TiO2 was metallic, since it has a boiling point of 1830 degrees and forms on the outer layer of titanium metal when exposed to oxygen in the atmosphere.

Then I put TiCl4 is ionic, and can dissolve in solution.

TiCl4 is covalent, not ionic. And TiO2 is ionic, not metallic.

Reply 2222

Qwob

1

Original post by Bello08

TiCl4 is covalent, not ionic. And TiO2 is ionic, not metallic.

Just researched it and you're right. Really annoyed at that, at least 3 marks dropped on that question now. They have never mentioned bonding between transition metals and other atoms before unless its complex ion formation. Damn you Edexcel. :angry:

Reply 2223

croony

i said regarding the fuel cell one that it is more efficient. is that right for 1 mark?

Reply 2224

croony

i just need 75 ums to get an A. i know i did **** cos of my panic attack (never had one before) the paper wasnt even hard.. do you reckon if i dropped 34 marks roughly i can still get that?

Reply 2225

Blob2491

12

What did you guys put for why TiCl4 + Na is evidence for a redox reaction or something?
Grade boundary predictions anyone?

(edited 10 years ago)

Reply 2226

croony

what did you guys put as use for the azo compund? i put coloured dye for clothing

Reply 2227

blossomx

20

Original post by Blob2491

What did you guys put for why TiCl4 + Na is evidence for a redox reaction or something?
Grade boundary predictions anyone?

i put Na goes from 0 and +1 so it's oxidised, titanium goes from +4 to whatever it ended up as (can't remember)

Original post by croony

what did you guys put as use for the azo compund? i put coloured dye for clothing

i put that too

Reply 2228

mrhedgehog

14

Original post by croony

what did you guys put as use for the azo compund? i put coloured dye for clothing

Yeah I put a dye for inks, but I reckon they just wanted the word 'dye' really

Reply 2229

mrhedgehog

14

Original post by Qwob

I put that, maybe they'll accept both...

Yeah I dont see why not because sulfuric acid can lose 2 H+ ions.
What about the one with butylamine and ethanoic acid. I put ch3ch2ch2nh3+ ch3coo-

Reply 2230

croony

and what did you guys write about why the complex ion is coloured? i wroter the water ligands split the d subshell into two different energy levels. d-d transition occurs when electrons in lower energy level absorb light of certain frewuencies and move to a higher energy level and that the frequency of light absorbed compliments the colour of the complex. is that enough for 3 marks or is there anything specific they wanted.. afterall its edexcel?

Reply 2231

AtomicMan

13

Original post by mrhedgehog

Im pretty sure that when butylamine and sulfuric acid react the same is (ch3ch2ch2ch2nh3)2 ^2+ So4^2-

It cant be that, because the nitrogen only has 1 lone pair of electrons, so can only accept one proton

Reply 2232

Blob2491

12

Grade boundary predictions anyone?

Reply 2233

shumen9523

6

Original post by AtomicMan

It cant be that, because the nitrogen only has 1 lone pair of electrons, so can only accept one proton

Yes, but if you look at the formula more closely you'd notice that there are two butylamine molecules involved in the salt.
(it's like (NH4)^2SO4))

(edited 10 years ago)

Reply 2234

croony

for the electrode one i wrote the wrong equation as in picked only one that produced OH- and based on E cell value on that so would there be error carried forward? also how many marks was it to calculate the e cell value?

Reply 2235

mrhedgehog

14

Original post by AtomicMan

It cant be that, because the nitrogen only has 1 lone pair of electrons, so can only accept one proton

Yeah my molecule has the nitrogen with one H+ only but there are 2 butylamines

Reply 2236

Bello08

Original post by Qwob

Just researched it and you're right. Really annoyed at that, at least 3 marks dropped on that question now. They have never mentioned bonding between transition metals and other atoms before unless its complex ion formation. Damn you Edexcel. :angry:

Well I thought it was pretty obvious that TiCl4 was covalent. Firstly, it said it was a liquid at room temp, which is the big give away. Secondly, you should know that some metal chlorides like AlCl3 are actually covalent, therefore it is reasonable to assume that TICl4 will also be. Remember that this specification requires you to carry over knowledge from all previous units, so they can test you on anything from units 1, 2 or 4 in unit 5.

Reply 2237

Bubblezzzz

For that question, was it asking why there is a difference in boiling point? Or did it want a detailed explanation on the bonding in the molecule itself?