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Reply 120
Original post by madrevision
I wondered about that for quite some before I was just like it's freaking room temperature lol:colondollar:


Dat feels, bro :3
F331 was an amazing paper. Pretty sure OCR has something demonic planned for F332.
Reply 122
Original post by nukethemaly
F331 was an amazing paper. Pretty sure OCR has something demonic planned for F332.


just hope grade boundaries won't be annoyingly high :/
Original post by ashxx
just hope grade boundaries won't be annoyingly high :/

This. I'm one of those people that doesn't make many proper mistakes, but makes loads of the god damn stupid ones that make you feel like beating yourself with a cricket bat after the exam finishes. I thrive on hard exams, with low grade boundaries to cover my stupid moments :biggrin:
Reply 124
Original post by King Hotpie
This. I'm one of those people that doesn't make many proper mistakes, but makes loads of the god damn stupid ones that make you feel like beating yourself with a cricket bat after the exam finishes. I thrive on hard exams, with low grade boundaries to cover my stupid moments :biggrin:


jee i know exactly what you mean -_-
Reply 125
Hello everyone!! :biggrin:
Today I shall start revising for this exam (I want 129 ums :argh:)

Here are some notes :')
Original post by tigerz
Hello everyone!! :biggrin:
Today I shall start revising for this exam (I want 129 ums :argh:)

Here are some notes :')
omg yes! thank you so much i was really struggling to find structured notes or f332 :biggrin:
Reply 127
Original post by madrevision
omg yes! thank you so much i was really struggling to find structured notes or f332 :biggrin:


Hahaha no problem! Also, feel free to let me know if they need correcting or if I need to add more info :smile:
Reply 128
Could someone pleeeeease explain to me question 3a) from the Jan. 2011 paper?!
okay guys so on the spec it says
use a radical mechanism as a model to explain the reaction of alkanes with halogens (a radical chain reaction in the presence of UV radiation to form halogenoalkanes)
Original post by NielsBohrsDad
okay guys so on the spec it says
use a radical mechanism as a model to explain the reaction of alkanes with halogens (a radical chain reaction in the presence of UV radiation to form halogenoalkanes)


what exactly do they mean by this?

& also does anyone know what exactly it is from the storylines that we need to know for ES and PR?
It would be grate if somebody could tell me the specific topics/storylines i need.
Thanks
Original post by Branny101
Could someone pleeeeease explain to me question 3a) from the Jan. 2011 paper?!

it's a bit like when you have to calculate empirical formula, only on this question you're given fractions. just do (1/3) divided by Mr of KCl and (2/3) divide by Mr of NaCl and then divide both answers by the smallest one and you should get 1 and something else.
feel free to ask me for a better explanation if you still don't understand :smile:
Reply 132
Original post by NielsBohrsDad
okay guys so on the spec it says
use a radical mechanism as a model to explain the reaction of alkanes with halogens (a radical chain reaction in the presence of UV radiation to form halogenoalkanes)


I;m not entirely sure if this is what you were asking for but here you go:

http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch04/ch4-7.html
Reply 133
Original post by madrevision
it's a bit like when you have to calculate empirical formula, only on this question you're given fractions. just do (1/3) divided by Mr of KCl and (2/3) divide by Mr of NaCl and then divide both answers by the smallest one and you should get 1 and something else.
feel free to ask me for a better explanation if you still don't understand :smile:


Heyy thanks for the reply, I kind of get it but I can't work methodically unless I know where the method is coming from, if you know what I mean?

Why is it that its a 1/3 or 2/3 divided by Mr?
Why is it that after the first division you divide it by the smallest number?

Thanks in advance! :awesome:

Posted from TSR Mobile
Original post by Branny101
Heyy thanks for the reply, I kind of get it but I can't work methodically unless I know where the method is coming from, if you know what I mean?

Why is it that its a 1/3 or 2/3 divided by Mr?
Why is it that after the first division you divide it by the smallest number?

Thanks in advance! :awesome:

Posted from TSR Mobile

Ok so basically you know that out of a total of 3, 2 units of the mass is NaCl and 1 unit is KCl. Now you are asked to find the mole ratio. Using n=m/Mr, you find the moles of NaCl = 2/58.5 and the moles of KCl = 1/74.6.
Now as for the ratio if you had 4 dogs and 8 cats, you would divide by the smallest to get the simplest ratio. i.e the ratio of dogs: cats is 1:2 (excuse my weird example lol ) so you do the same to find the ratio of moles. Does that help explain the method ?:smile:
Reply 135
Original post by madrevision
Ok so basically you know that out of a total of 3, 2 units of the mass is NaCl and 1 unit is KCl. Now you are asked to find the mole ratio. Using n=m/Mr, you find the moles of NaCl = 2/58.5 and the moles of KCl = 1/74.6.
Now as for the ratio if you had 4 dogs and 8 cats, you would divide by the smallest to get the simplest ratio. i.e the ratio of dogs: cats is 1:2 (excuse my weird example lol ) so you do the same to find the ratio of moles. Does that help explain the method ?:smile:


Thanks! I think I geddit now :colondollar:
Reply 136
This document may be useful as it explains some of the reactions (I am aware that some of it is irrelevant to F332) :smile:
Reply 137
sorry if this has already been mentioned or posted on another thread, but does anyone have a list of all the specific reactions and conditions that are needed?
Reply 138
Original post by ashxx
sorry if this has already been mentioned or posted on another thread, but does anyone have a list of all the specific reactions and conditions that are needed?


I've posted it either in this thread or the one for the pre-release :smile:
Reply 139
Heres some more model answers:

Making a halogenoalkane from an alcohol
- Shake methylpropan-2-ol with conc. HCl (keep releasing the pressure)
- Allow the mixture to settle and run off the lower aqueous layer, leaving the impure halogenoalkane
- Neutralise the excess acid by adding sodium hydrogen carbonate solution and run the lower layer off
- Add distilled water and run off the lower layer (this gets rid of any remaining inorganic impurities)
- Remove any remaining water by adding anhydrous sodium sulfate (a drying agent)
- Remove remaining organic impurities by distilling the mixture

The greenhouse effect
- The sun emits energy, in the form of UV light, onto the Earth
- The Earth absorbs this energy and re-emits IR
- CO2, in the troposphere, absorbs some IR in the 'IR window'
- making the bonds vibrate more
- this turns into kinetic energy, raising the temp.
- some O2 molecules radiate IR which warms the Earth
- more CO2 means more radiation and hence a warmer Earth

What happens to the temperature in the atmosphere as you move away from the Earths surface to the top of the stratosphere?
- the temperature decreases in the troposphere and you move away from the Earth
- because hot gases near the Earths surface rise and cool
- within the stratosphere
- the temperature of the atmosphere rises as you move away from the Earth
- due to exothermic reactions

How do we know that halogenoalkanes deplete ozone?
- They break down in the presence of UV light to form radicals
- the radicals catalyse the breakdown
- low concentrations of ozone were found above the antarctic

Why do reactions between atoms occur more quickly at the top of the troposphere?
- conc of gases is higher at the top of the troposphere
- so more collisions occur between the molecules per second

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