OCR B Salters - F335 Exam - 15 June 2011

I'm pretty sure it wasn't a mistake; after their D1 debacle, they'd have been checking everything! It's probably due to the halogen atoms changing it. And how does your HOC get to see the paper? No-one's allowed it till the day after?

He was the Exam obligerator guy
Lol no the exam is written like a yer in advance apparently ad when they sent the school the exams they werent aware of the d1 thing, plus my biology teacher said there was a mistake on an AS bio one and a geography one?

Bastard OCR.

Btw sorry if any of that doesn't make sense my iPhone autocorrects every sodding word

Reply 761

04ayasin

Original post by ManPowa

The answer was (secondary) Amine nothing else.. not alkene or benzene.

I think I put amide :frown:

Reply 762

Mens rea

Original post by ManPowa

Comment - If your total entropy was positive, then a fuse will not be required as the reaction is spontaneous. However, if your toral entropy change was negative, then a fuse will be required. I think on the mark scheme, this will be ECF as even if you get the wrong answer but you can still get the mark for the comment.

Forgive me for being dense, but isn't a fuse something that breaks a circuit if the current runs too high??? This question stumped me completely, I blagged it spectacularly though - the marker will probably find it quite amusing

Reply 763

Mathelete

Original post by Tetanus

What did everyone get for the mass? I got 12g.

I got it through n = V x C / 1000 then n = m / Mr??

I got that too! And it is right!! My chemistry teacher checked it!!

Reply 764

Mathelete

I need 107/120 UMS for an A!

Bye Bye UCL!

:frown:

Reply 765

04ayasin

Original post by Mens rea

Forgive me for being dense, but isn't a fuse something that breaks a circuit if the current runs too high??? This question stumped me completely, I blagged it spectacularly though - the marker will probably find it quite amusing

Yes but there are also fuses you light. Its sort of like the wick of a candle, except burns a lot faster.

Reply 766

arianna.k

7

Original post by Mathelete

I got that too! And it is right!! My chemistry teacher checked it!!

OMFG ARE YOU KIDDING ME??!!

i put 12g thinking 'there is no way in hell this is right'

was it 4 marks as well??

Reply 767

tom108

Original post by arianna.k

OMFG ARE YOU KIDDING ME??!!

i put 12g thinking 'there is no way in hell this is right'

was it 4 marks as well??

Wasnt it just 120 x 0.1 ?? (in short)

Reply 768

Mens rea

Original post by 04ayasin

Yes but there are also fuses you light. Its sort of like the wick of a candle, except burns a lot faster.

Oh yeah... :facepalm2:

thanks bro

Reply 769

arianna.k

7

Original post by tom108

Wasnt it just 120 x 0.1 ?? (in short)

but it was 4 marks...so where did the other marks come?

Reply 770

ManPowa

7

What did everyone put for the question, 'Explain, in terms of intermolecular bonds why ch2BrCh2Br and Ch2BrCh2Cl dissolve in each other, but do not dissolve in water.

It was 4 marks.

Reply 771

alexlemon2

Original post by arianna.k

OMFG ARE YOU KIDDING ME??!!

i put 12g thinking 'there is no way in hell this is right'

was it 4 marks as well??

Same, this was the last question that i had left to do and basically had no idea what to actually do and ended up with something like 120x0.1 which looked totally wrong :redface:

Reply 772

brendan.

12

Original post by laurenl93

He was the Exam obligerator guy
Lol no the exam is written like a yer in advance apparently ad when they sent the school the exams they werent aware of the d1 thing, plus my biology teacher said there was a mistake on an AS bio one and a geography one?

Bastard OCR.

Btw sorry if any of that doesn't make sense my iPhone autocorrects every sodding word

Yeah, all exams are written in advance, but OCR also state on their site that they have 'exhaustively checked' the remaining papers to see if there are any other mistakes.
http://www.ocr.org.uk/news/2011/item_020.html
Also it says at the top of the data sheet above the table of chemical shifts that the values can change depending on solvent, concentration and substituents. So even though it wasn't wanted to use these, it technically isn't wrong?
http://www.ocr.org.uk/download/kd/ocr_9911_kd_gce_data.pdf

Reply 773

bala123

Original post by ManPowa

What did everyone put for the question, 'Explain, in terms of intermolecular bonds why ch2BrCh2Br and Ch2BrCh2Cl dissolve in each other, but do not dissolve in water.

It was 4 marks.

Well i put down

1. the two halogenoalkanes form permanent-permanent dipole bonds and water molecules form hydrogen bonds.

2. for the halogenoalkanes to dissolve in water then they need to break the hydrogen bonds in water first. but hydrogen bonds are stronger than permanent-permanent, so they dont dissolve in water.

3. they dissolve in each other because they both form permanent-permanent due to differences in electronegativity between halogen and carbon.

(edited 12 years ago)

Reply 774

mina.

Original post by Jake200493

Omg- loved it! All the stuff I could do and no evil nitrogen cycles and catalysis!!

How I wish there was nitrogen cycle and catalysis instead of those mass questions..

Reply 775

04ayasin

Original post by bala123

Well i put down

1. the two halogenoalkanes form permanent-permanent dipole bonds and water molecules form hydrogen bonds.

2. for the halogenoalkanes to dissolve in water then they need to break the hydrogen bonds in water first. but hydrogen bonds are stronger than permanent-permanent, so they dont dissolve in water.

3. they dissolve in each other because they both form permanent-permanent due to differences in electronegativity between halogen and carbon.

I thought the dipole cancelled out so it didn't have one. I put a dipole is induced by the molecule with the permanant dipole and that it forms permanant dipole induced dipole. The reast I got the same as you. I also added that halogenoalkane did not offer enough energy to break the hydrogen bond.

Reply 776

jpurkis1

Original post by ManPowa

What did everyone put for the question, 'Explain, in terms of intermolecular bonds why ch2BrCh2Br and Ch2BrCh2Cl dissolve in each other, but do not dissolve in water.

It was 4 marks.

I put that they have similar IM forces (permanent dipole-permanent dipole interactions), and these have similar energies to break (?!).
No solution formed with water as strong H-Bonding between water molecules requires too much energy to break than is replaced by the formation of ion-dipole attractions; therefore energetically unfavourable and no reaction.

:confused:

Reply 777

mina.

Original post by ManPowa

Hard paper, the last question was the most challenging ever. Loads of As themes, nothing on reaction of arenes :/ wat the hell. Instead, they did the complete opposite and put in reaction of bromine with an alkene. The hardest F335 paper ive seen so far, hopefully low grade boundaries. The last question completely got me, and was it me, or was there awfully a lot of question on bonding around 20 marks.
And the first question was the best :biggrin: