Edexcel chemistry resit unit 1

isnt the ions of oxygen 18

O18 +
and
O18 2+

the hess law cylce one should give a negative value
delta H1 - delta H2 = enthalpy change

Reply 47

natcupine

6

Original post by sataw

also are people really sure the a boundary will be as high as 67? It seemed like an odd paper to me, there were a few things that I hadn't seen before that could trip people up - like the polarisation question, the one about bonds and some of the one markers.

I agree I thought it was weird - never seen a lot of those questions before. I don't think they'll be as high as people are predicting (or I hope haha)

Reply 48

Angus09

Original post by beanigger

isnt the ions of oxygen 18

O18 +
and
O18 2+

the hess law cylce one should give a negative value
delta H1 - delta H2 = enthalpy change

it told you in the question that they had mass number 16 as they were isotopes.

Reply 49

Angus09

Original post by Earth1

I put something like the mass of an atom of oxygen 16 is not exactly 16 g

i put the same then i put the mass or 1/12 of carbon 12 is exactly one just incase they wanted more.

Reply 50

jaylo123

1

Original post by natcupine

I agree I thought it was weird - never seen a lot of those questions before. I don't think they'll be as high as people are predicting (or I hope haha)

yep me too! Cant see how it will be that high there were lots of small weird questions im thinking (hoping) more between 64 and 67 not 67 and 70

Reply 51

jaylo123

1

Original post by beanigger

isnt the ions of oxygen 18

O18 +
and
O18 2+

the hess law cylce one should give a negative value
delta H1 - delta H2 = enthalpy change

I did that too, think its wrong but hopefully if you drew the more charged ion getting deflected more we'll get ECF marks

Reply 52

Original post by jaylo123

Are edexcel going to fairly standardise the boundaries?? Every year the students retaking AS are helped by those who mess it up in the year below, lowering the boundaries.. this year there are no AS students! I'd say 65/80 is fair for an A?

The highest its been recently is 66 and i think a lot of people found this easy because it's the second time of asking. Thoughts?

I think you're also forgetting that the people who usually get As in the exam first time round didn't take that exam because they already did well first time round. So that leaves re-sit students who didn't do well first time round. Some of them might have not put much effort into the re-sit either.

I think the GBs will be moderately high as it was pretty straight forward, but I've heard some people suggest 70+ for an A which is absolute nonsense. It will be around 67 for an A imo.

(edited 7 years ago)

Reply 53

username2592579

Original post by jaylo123

I did that too, think its wrong but hopefully if you drew the more charged ion getting deflected more we'll get ECF marks

well when u ionise something in mass spectra
you can get a +1 charge and +2 charge and more etc etc
i think this because in previous papers i saw a question talking about what would happen to m/e value if the charge on the ionised ion was +2? so i assume that can happen and should be the correct answer

Reply 54

Original post by beanigger

well when u ionise something in mass spectra
you can get a +1 charge and +2 charge and more etc etc
i think this because in previous papers i saw a question talking about what would happen to m/e value if the charge on the ionised ion was +2? so i assume that can happen and should be the correct answer

The ions should've been 16O+ and 16O---160+.

Hess Cycle should've been +71kj.mol^-1

Reply 55

username2592579

Original post by ASTK98

The ions should've been 16O+ and 16O---160+.

Hess Cycle should've been +71kj.mol^-1

the hess cycle is always negative value lol

i cant remember what i got but its always negative

Reply 56

No it isn't always negative lol. My teacher went through that question. It's +71.

Reply 57