OCR B (Salters) Chemistry F331 (Chemistry for Life) Thursday 23rd May Exam Discussion

I use http://www.4college.co.uk/index.php

Reply 61

CallMeBatwoman

Original post by Kathiye

I'm not too sure of what you mean exactly by 'maths', but I'll try to give you a list:

Working out relative atomic mass from a mass spectrum
Half lives
Reacting masses (eg working out number of moles of a reactant and using it to find the mass of a product)
Concentrations
Empirical Formulas
Gas volumes
Avogadro's Constant (sometimes they ask how many particles/moles there are)
c=λv
E=hv
Enthalpy changes using bond enthalpies (sometimes linked to the above three)
Enthalpy changes using enthalpy changes of reactions
Hess, using the above
Bond angles, if that counts. xD
E=mc(change in)t

I think that's all! In other words, a lot.

I know its a lot, thank heavens I know most of it :tongue:

thankyou so much!

Reply 62

CallMeBatwoman

Original post by Mtheodore

1. Electron density
2. Bond enthalpies
3. Energy transferred (calorimeter)
4. Hess's Law
5. Percentage by mass
6. Empirical formulas
7. Half lifes
8. Relative abundance of isotopes
9. Calculations involving moles, volumes and mass
I think thats pretty much everything

Thank you so much for the help :smile:

Reply 63

Original post by TheNote

i don't think we need to know:
c=λv since that's a speed of light thing which we don't go near

Really? I'm sure I remember it coming up in a past paper... and it is in the book. Maybe I'm just imagining the question! It can't hurt to be aware of it, though.

Reply 64

Original post by Kathiye

Really? I'm sure I remember it coming up in a past paper... and it is in the book. Maybe I'm just imagining the question! It can't hurt to be aware of it, though.

i've never come accross it, and I don't see it in the revision guide or the spec.
"differences: bright/coloured lines on a black background

or black lines on coloured/bright
background;

understand the relationship between the energy emitted or absorbed

and the frequency of the line produced in the spectra;

∆E=hν"

(edited 10 years ago)

Reply 65

Original post by TheNote

i've never come accross it, and I don't see it in the revision guide or the spec

It was probably just that xD But like I said, it's mentioned in the textbook. They could just decide to be weird this year.

... Not trying to worry anyone or anything. :colondollar:

Reply 66

Original post by Kathiye

It was probably just that xD But like I said, it's mentioned in the textbook. They could just decide to be weird this year.

... Not trying to worry anyone or anything. :colondollar:

hahaha no problem what page is it on?

Reply 67

Original post by TheNote

hahaha no problem what page is it on?

I can't remember exactly, but it's the one about the wave theory of light, I think?

Reply 68

Original post by Kathiye

I can't remember exactly, but it's the one about the wave theory of light, I think?

oh i found it page 119 or something, it's giving you a general explanation and background on electromagnetic radiation so you understand what's going on rather than they just throwing E = hv at you and hoping for the best, however it's not in the entire spec so don't expect it to be the exam.

Reply 69

3raindrops

hope it all goes well, and they don't put in anything we don't know

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Reply 70

autodidactmedic

Does anyone know what calculations we have to do for mass spec?

Reply 71

SyedaK

Original post by autodidactmedic

Does anyone know what calculations we have to do for mass spec?

The relative abundance one

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Reply 72

Original post by SyedaK

The relative abundance one

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Original post by autodidactmedic

Does anyone know what calculations we have to do for mass spec?

Say if you got isotopic masses with abundance
16-65%
17-35%

Ar of element=
(16 X 65)+(17 X35)

= 16.35
----------------------
100

Reply 73

So apparently trying to help people gets me a neg... oh well. I had to get one somewhere.

Good luck everyone! Hopefully it won't be as weird as my biology exam xD

Reply 74

username1044065

Last minute revision notes! http://getrevising.co.uk/revision-cards/348137#11

Reply 75

I hate it when they say why the practical procedure led to a less negative value for enthalpy change of combustion of....
Wat do you say?
Once they didn't allow nonstandard conditions used in the MS and didn't allow even evaporation of fuel from wick

Help

Reply 76

What do they mainly accept for above ^?

Reply 77