A2 OCR Chemistry B F334 - June 2015

what ums do we need for an A out of 600?

another awful question. You had to convert the time into rate by dividing by 1. then when you compared the increases it was clearly 1st order. another horrible way of making a question more difficult than it needed to be by OCR

what ums do we need for an A out of 600?

I just put C=ON-H.

I think you've over complicated it, it's just that it had a constant half life of something like 120 hours i think which shows its first order

That DNA question was do-able but the different amounts of hydrogen bonding was just there to give the biologists a hand..

But it said to use the data, no indication of half life there.
So I realised that there was a difference of 70 hours between 30 and 100, then 220 and 290. I calculated the ratio between the concentrations for both times and I got 0.77 for both of them, so it was first order.

i worked out that i need 96-106 in f335 for an A to be secured if i am still going to uni

right do you guys reckon this answers OK for the DNA thingummy....
CG = 3 hydrogen bonds (pyrimidine)
AT = 2 hydrogen bonds (purine)
Hydrogen bonds break between bases and two strands of DNA are reformed using DNA polymerase via semi-conservative replication

Btw why were we doing the ocr biology exam today, I swear that we were meant to have f334 CHEMISTRY exam today..... :/

Hydrolysing that big polymer with the arene groups should have gotten you one with NH3+ and the other with a carboxyl group and the OH untouched,

Percentage by mass question I got 97.1%

The choking gas I wrote ethanoic acid

The toxic gas from the steel recycling bit i wrote chlorine gas

The thing that reacts with iodine was the one under it in the table

TLC question was nice

the biology DNA replication was nice, my teacher used some retarded way of remembering that guanine and cytosine form three H bonds so that made me smile when it came up

Drawing two amino acids reacting together is a godsend OCR y u give free marks thanks very much, aswell as the enzyme v ph graph <3

I just thought the paper was the nicest they've given in a long time. Think about it, no long ass question about rates, multi step reactions etc, no strange curveball mole calculation

I reckon the only things I know I got wrong was the IR spectra, and the two 1 markers about combinational chemistry and improving medicines

In the Electrochemical cells diagram, all ions were in solution right? with 2 platinum electrode

Whose got OCR b physics g494 tomorrow. That'll be fun!!!

same man, its a piss take