OCR Salters Chemistry B F332 Advance Notice Jan 2011 Understanding Our Changing Atmos

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What did you put for:

a source of propene?

reagents and conditions for converting propene to propan-2-ol?

reagents and conditions for converting propane to 2-chloropropane?

I put:

1) Crude oil

2) Phosphoric acid catalyst 60atm 300 oC temp

3) Dilute HCL (shake at) room temp and pressure.....?

Reply 61

patrick93

Original post by tkoki1993

For 1. I would've said crude oil

that's what i said. It was only a one mark question

Reply 62

hidden_desire

Original post by tkoki1993

what did people get for the question about equilibria?

I got a little confused :frown:

But I wrote that increase temp would decrease yield as it would favour the endothermic reaction ( :s:

) and increase pressure would increase yield as it would favour the forwards reaction (more moles)

I have no idea :/

Reply 63

Darthdevidem

What did you guys put for how did they find out how ozone depleted

Reply 64

jpurkis1

Original post by hidden_desire

I put:

1) Crude oil

2) Phosphoric acid catalyst 60atm 300 oC temp

3) Dilute HCL (shake at) room temp and pressure.....?

Same.

Original post by hidden_desire

I got a little confused :frown:

But I wrote that increase temp would decrease yield as it would favour the endothermic reaction ( :s:

) and increase pressure would increase yield as it would favour the forwards reaction (more moles)

I have no idea :/

I got that the increased temp would decrease yield as higher temperatures favour endothermic side. Higher pressure increases yield as it favours the side with least gas molecules, and so moves to the left...that's if I'm remembering correctly...

(edited 13 years ago)

Reply 65

jpurkis1

Original post by Darthdevidem

What did you guys put for how did they find out how ozone depleted

How'd you mean?

I just put about how the British antarctic survey used a converted spy plane and sateliites to gather data on ozone at different points in antarctica. They also performed mass spectrometry (I think!) on samples they collected.
The data was originally overlooked as the data gathered was so low it was filtered out by the computers they used. It took them a while to find it amongst all the other samples. :confused:

Reply 66

gozatron

Original post by jpurkis1

Crap I put infrared...

Reply 67

coffee345

what did everyone get for the titration question and ratio?

for titration q:
acid was 2.5x10^-3moles
2.5x10^-3 moles
concentration was 0.124moldm-3??

ratio i got 1:3??

Reply 68

coffee345

Original post by gozatron

Crap I put infrared...

didnt they ask something about infrared i said look for a peak at 1720 to 1740??

Reply 69

jpurkis1

Original post by coffee345

what did everyone get for the titration question and ratio?

for titration q:
acid was 2.5x10^-3moles
2.5x10^-3 moles
concentration was 0.124moldm-3??

ratio i got 1:3??

You've got a good memory...

I can't remember what I put for the titration, but that sounds about right.
The molar ratio question was annoying, because everyone in my class who retook it got different answers. I got 1 : 0.4 :s-smilie:

Reply 70

coffee345

Original post by jpurkis1

lol im worried about the exam thats why D:

did you get burette for equipment?

and how did you get 0.4...because i got that but changed it to 3 :frown:

Reply 71

Darthdevidem

How many marks do you think we'll need for 90 UMS or 100UMS?

For 90 I reckon 82/100 raw marks

For 100 I reckon 90/100 raw marks

Anyone else agree?

Reply 72

jpurkis1

Original post by coffee345

lol im worried about the exam thats why D:

did you get burette for equipment?

and how did you get 0.4...because i got that but changed it to 3 :frown:

I sort of guessed; I didn't get it at all...

And yes, burette.

Reply 73

tom108

What did everyone put about the equilbrium question?
I put increase yield for Temperatrue
and decrease yeield for pressure?

Am i wrong? :frown:

I also put the ethene was used to make Plastics? Is that right?

(edited 13 years ago)

Reply 74

MyJunkIsYou

what did people get for the bond enthalpy question? thought it was a bit cheeky they changed it round from way they've done it in all the past papers. i think i got something like 348kJ :/

and the mole ratio one? how were you supposed to work it out? had no idea what to do, moved on and just bunged down 1:0.5 in a last minute rush

Reply 75

jpurkis1

Original post by jpurkis1

That's what I put.

Reply 76

tom108

Original post by MyJunkIsYou

Where did you get 343kj from? I think i got mine wrong? My answer came to summin like 10^-19

Reply 77

coffee345

Original post by tom108

Where did you get 343kj from? I think i got mine wrong? My answer came to summin like 10^-19

i got something x10^-19

and for the bond enthalpy one i got something x10^-40 O.O"

Reply 78

MyJunkIsYou

Original post by tom108

Where did you get 343kj from? I think i got mine wrong? My answer came to summin like 10^-19

oh yeah well i got something to the 10^-19 for the first part, calculating the energy for a single bond.

And then it wanted the bond enthalpy in kj if i remember. that's what i got 348kj for. but then again i wasn't sure whether to divide or times by the avogadro constant so knowing me i probably did the wrong thing!

Reply 79

jpurkis1

Original post by tom108

Where did you get 343kj from? I think i got mine wrong? My answer came to summin like 10^-19

The answer of X * 10^-19 needed to be multiplied by avogadro's constant (6.02 * 10 ^23) to work out the bond enthalpy. They might accept answers in a range of between 320 - 370, from what I've seen and heard from people.