OCR Chemistry B (Salters) F334/F335 Exam Thread 2016 (14th/22nd June)

Really awaiting that unofficial markscheme. Have no idea how this went. Very different from other papers in my opinion

Where is it released? And how long does it normally take for an unofficial mark scheme to come out?

Never come up before. It was vague so I talked about orders with respect to enzyme and substrate. Basically first order and after the plateau zero order. Both involved in rds as both in rate equation rds was the first step as it was reversible?

Not 100% sure then again nobody is

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For the question asking to draw the structure of the E/Z isomers was it supposed to be drawn as skeletal or full structural?

What did people put for the vapours thing about high temperatures??

1.
Secondary structure -
Tertiary structure -

Describe active site and it's function -

Partial hydrolysis of trypsin -

Benefits of trypsin > bromate (v) catalyst - higher atom economy, speeds up reaction, reduces need for flammable/toxic solvents

5 marker on ESC, EP, rate orders and substrates stuff -

Rate of reaction at 70 degrees -

2.

Electrodes / tank, which solution? -

Coating steel? - zinc

Why was there a membrane -
Salt bridge

Iron forming red brown precipitate

3.
Bromine number

Prove excess

Bromine number [5] -

Why was there E/Z isomerism? - CC double bonds cant rotate

Draw isomers

Transition metal heterogeneous catalysis - provides a solid surface for reactants to adsorb to; 3d electrons make weak bonds to hold them in place

Following BrO3- reaction -

Rate equation -

Temperature affecting reaction rate? - increases and value of k increases

4.

Draw polyester -

What condensation polymer is this?-
Polyester

Why did Carothers go ahead with polyamides?

5.

Oxidising aldehyde to carboxylic acid -
Acidified dichromate

IR spectrum -
Apocylsin

Mass spectrum -

Recrystallisation -

Nucleophillic substitution -


Can we get going at filling that, I might have missed a few questions and only answered the ones for certain.

It just said structural so you can draw anything

Was the standard electrode potential for the vanadium system +180 V?

I put first order for both. The rate never quadrupled so it cant be second order

thank goshhhhhh! thank you so much I can now stop dwelling over it

I go 195g, not sure where people got the 390g from as the mass of the c6h10 was 82 then bromine is 79.9x2 so you do (79.9x2)/ 82 then multiply that by 100

What did people put for the vapours thing about high temperatures??

That is what I got too because didn't it say they needed to have the same sign?