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AQA CHEM1: 15th May 2012

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Anyone going to tell me q 1e on jun 10 lol

Mass of desired product divided by total mass of reactants. x100.

im not sure why they've used 438 as the denominator. the numerator is definately 202.

Reply 341

choco.chip

Original post by W4L1Y

Biology AQA? If yes then i made so many silly mistakes unbeliveable FFS :angry:

yup, can't see how chemistry can be worse
so hopefully it's a good paper tomorrow :smile:

Reply 342

Jack_Smith

Just did papers before 2009 and it aint all that bad :/ Lets just hope our paper would be good tommorow! Jan 2012 threw me off guard Got a C :frown:

Reply 343

W4L1Y

Original post by Jack_Smith

Just did papers before 2009 and it aint all that bad :/ Lets just hope our paper would be good tommorow! Jan 2012 threw me off guard Got a C :frown:

Looking back jan 2012 wasnt tht hard and had very low grade boundries 53 for an A

Reply 344

MustyQ

need help anyone,
right AsH3 has 5 outer electrons but have no idea why as its electron number is 33?

Reply 345

Mohja

Could anyone help me as well? :smile:

A sample of the metal silver has the relative atomic mass of 107.9 and exists as
two isotopes. In this sample, 54.0% of the silver atoms are one isotope with a
relative mass of 107.1

Calculate the relative mass of the other silver isotope.

Reply 346

Voglie

Original post by mynamee

Anybody care to explain how you work out:
3(b)(i) Jan 2012
C5H14 has structural isomers.
Deduce the number of structual isomers with the molecular formula C6H12.

Mark scheme says its 5... I don't understand why, there are no halogens.

Could someone help me out, maybe by drawing it in paint of something, thanks

Draw out all the possible chain isomers c6h14, c5h12ch3, c4h10ch3ch3. And then look at where you can move the CH3 group(s) if anywhere. Such as in c5h12ch3, you can move the ch3 group into 2 places forming 2 isomers, and for c4h10ch3ch3, the 2 methyl groups can either be position on the second carbon in the c4 chain, or they can both be positioned on separate carbons (carbon #2 and 3) creating 2 more isomers. Therefore the total number of isomers of c6h14 is 5.

Hope that helps.

Reply 347

Silver2

is the exam in the morning or he afternoon. i wrote down morning.. but on the website it says afternoon???

Reply 348

The Assassin

Original post by Mohja

Could anyone help me as well? :smile:

The other isotope is 100-54 = 46%.

107.9 = ((54 x 107.1) + (46 x ???? )) / 100

Solve and you get 108.8

Reply 349

Jambone2

Original post by Mohja

Could anyone help me as well? :smile:

(0.54 * 107.1) + (0.46 * x) = 107.9

0.46x = 107.9 - (0.54 * 107.1) = 50.066

x = 50.066 / 0.46 = 108.8

Reply 350

Mohja

Original post by The Assassin

The other isotope is 100-54 = 46%.

107.9 = ((54 x 107.1) + (46 x ???? )) / 100

Solve and you get 108.8

How do I 'solve'? :confused:

(don't do maths)

Reply 351

iTwIsTeDmInDx

That method does work trust me, my chemistry teacher agreed

Reply 352

tinkerbell1109

I would advise to learn model answers for Core, one 3 mark question in the Jan 2012 C1 was repeated from a past paper. Even still, loads of questions are re-worded. This is a chance to pick up marks. Just keep doing past papers, its all practice. And know your differences between alkanes and -kenes. Very important! Good luck revising :smile:

Reply 353

It'sMeAgain

For Jan 11 Question 5 (c), 'Draw a diagram to show how the particles are arranged in aluminium and explain why aluminium is malleable.', does drawing delocalised electrons make you lose marks?

anyone?

Original post by Silver2

is the exam in the morning or he afternoon. i wrote down morning.. but on the website it says afternoon???

It's in the afternoon.

Reply 356

popnit

Original post by It'sMeAgain

For Jan 11 Question 5 (c), 'Draw a diagram to show how the particles are arranged in aluminium and explain why aluminium is malleable.', does drawing delocalised electrons make you lose marks?

No..shouldn't do

Reply 357

SWBL

On question 6)b)ii on June 2010, the answer is apparently 3-methylbut-1-ene - how do you know it is this and not 2-methylbut-1-ene? I'd be really grateful if anyone could help me out :smile:

Reply 358

Philippamalko

Original post by MustyQ

need help anyone,
right AsH3 has 5 outer electrons but have no idea why as its electron number is 33?

It is in group 5, so has 5 outer electrons. so in AsH3 it would be bonded to 3 Hydrogen atoms leaving a lone pair (if you were drawing it)

Reply 359

Philippamalko

Original post by SWBL

On question 6)b)ii on June 2010, the answer is apparently 3-methylbut-1-ene - how do you know it is this and not 2-methylbut-1-ene? I'd be really grateful if anyone could help me out :smile:

You count from the double bond side because this comes first, as it is but-1-ene, you count from there making the methyl group on the third carbon