Edexcel IAL, Unit 5: Transition Metals and Organic Nitrogen Chemistry. 22-Jun-2016

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Reply 140

bobbydylan

Original post by Mehodax

I think it should be B if you look at the ionic equation of oxidation of Fe2+ to Fe3+.
Which paper is this from?

No the answer is A, I thought B too.
It's from June 2011 or possibly Jan 2016 I'm not too sure though

Reply 141

username2153167

Original post by zahragoli97

The hydride ion H- is a strong reducing agent, a good nucleophile and a strong base. Which of the following changes could NOT be bought about by the ion. A)CH3CHO to CH3CH2OH
B) C2H5BR to C2H6
C) CH2=CH2 to C2H6
D) CH3COOH to CH3COO-
can someone help me with this question please(its unit 5)

The answer is C. All other reactions are reduction reactions, which can be brought about by the strong reducing agent H-. C, however, is an oxidation reaction.

Reply 142

username2153167

Original post by bobbydylan

No the answer is A, I thought B too.
It's from June 2011 or possibly Jan 2016 I'm not too sure though

It is from January 2016 (WCH05). The answer is A and here is why...

In order to prepare a suitable half cell, you have to have equal concentrations of Fe3+ anf Fe2+. The question asks you the mole ratio of FeSO4 and Fe2(SO4)3.

As you can see, although iron(II)sulphate gives rise to 1 mole of Fe2+ions, iron(III) sulphate gives rise to 2 moles of Fe3+. In order for the mole numbers of Fe2+ and Fe3+ to be equal, therefore, you need two moles of iron(II)sulphate and one mole of iron(III)sulphate. Both will give rise to 2 moles of ions.

Thus, the mole ratio of iron(II)sulphate to iron(III)sulphate becomes 2:1, therefore, A.

Reply 143

jwanjwan

if anybody will finish the exam before 9gmt message me i want to talk

Reply 144

Blazyy

Original post by jwanjwan

if anybody will finish the exam before 9gmt message me i want to talk

I finish at 6:40 GMT.
Haha, I won't talk to you.
I mean, that would be unfair.
I don't think anyone would talk to you.
They've prepared so hard for the exams.
What would make you think someone would like to do that?

Reply 145

It's dat boi

I think something on fuel cells, the stability constant (Facer book page 223) and Cr 3+ to Cr 2+ preparation techniques (Facer page 224 and CGP page 92) will all come up, haven't really seen much of them in previous past papers. Also you know that redox / transition metals will come up in section C since it was organic last year, that's all I can really predict for the exam. I think it will be hard but hopefully it will be like the other three papers they've given us this year which all weren't too bad (plus the A's in coursework in hope we all got) :smile:

Reply 146

Blazyy

Original post by It's dat boi

o **** waddup

Reply 147

lollypop101

does anyone have the international June 2015 Unit 5 paper and markscheme? thank u

Reply 148

Blazyy

Original post by lollypop101

does anyone have the international June 2015 Unit 5 paper and markscheme? thank u

It's available everywhere, why do you have trouble finding it?
http://www.physicsandmathstutor.com/past-papers/a-level-chemistry/edexcel-unit-5/

Reply 149

milogillot

can someone explain question 22 b) part ii) http://qualifications.pearson.com/content/dam/pdf/A-Level/Chemistry/2013/Exam-materials/6CH05_01_que_20150615.pdf you need to use the table from part b i)

Reply 150

lollypop101

Original post by Blazyy

It's available everywhere, why do you have trouble finding it?
http://www.physicsandmathstutor.com/past-papers/a-level-chemistry/edexcel-unit-5/

I literally found it on the same website 2 minutes after posting that but thanks

Reply 151

Blazyy

Original post by milogillot

can someone explain question 22 b) part ii) http://qualifications.pearson.com/content/dam/pdf/A-Level/Chemistry/2013/Exam-materials/6CH05_01_que_20150615.pdf you need to use the table from part b i)

For experiment A, you need to take the 2nd and 4th equations from the table and combine to get the vanadium product. (use the anti clock wise rule) This product will have a certain oxidation state, and the observation can be found out by linking the oxidation state with the colour.
Same thing for experiment B

Reply 152

milogillot

Original post by Blazyy

i applied the anti clockwise rule as usual but i got the signs the wrong way round

Reply 153

Blazyy

If you're a bit foggy on this topic try watching this video : https://goo.gl/LRO8jD

Reply 154

Rahatara Sadique

Hi everyone, would appreciate if anyone can help me out in these mcqs:

1. If the temperature of of the nitration of benzene is allowed to rise too high, dinitration and trinitration can occur. This is the evidence that the:
A) nitro group is electron withdrawing
B) nitro group is electron donating
C) delocalisation energy of nitrobenzene is greater than that of benzene.
D) delocalisation energy of nitrobenzene is less than that of benzene.
Why is the answer A? I thought it was B.

2. June 2015 IAL Q17 Why is the answer B?