OCR B Salters Chemistry Unit 2/F332 3rd June 2014

I got 0.008 % increase as the percentage increased from 0.03 % to 0.038%.
I put ethanoic acid twice, once for the infrared question with the spectrum, and once for the first part of 5.a) about the acidity?

Reply 81

ocelot92

7

Mn +4 to +2
I to -1 to 0

reducing agent = iodine, gets oxidised? from -1 to 0 gains in oxidation number

silver nitrate solution

AgCl, white precipitate formed

AgI might have also formed from the ash, so yellow precipitates may also be seen.

reduction = gain of electrons

percentage purity of impure iodine 73.8%

ir spectrum = ethanoic acid as 2500-3200cm-1 (not aldehyde nor ketone)

no absorption corresponding to O-H groups in alcohol so no ethanol present.

carbon monoxide = incomplete combustion

carbon monoxide = toxic, its not a component of photochemical smog is it? (I got this wrong)

CO2 is 3167 times more abundant

bond enthalpy is 285KJmol

high temperatures and high pressures not present in atmosphere so reaction cant go fast

last question = polymers and malolactic acid formation

(all I can remember)

Reply 82

JammyGit07

16

8x10^-3 as it was an exact copy of a previous question so you had to do:

8/1000000 * 100

Reply 83

Wood123

10

Original post by Fillly

27.1% increase for the ppm question anyone?

I rounded to 27%, do you think I'll still get marks?

Posted from TSR Mobile

Reply 84

username1084917

16

Did people put propagation for the reaction?

Reply 85

username1084917

16

And for the product for ethanoic acid, i put the prodcut was Ethanal, turned into an aldehyde

Reply 86

Gregorysmithem

unofficial unofficial mark scheme?

Reply 87

MasterOfTheSwag

1

Sorry about the order and lack of question numbers, and my answers may be wrong, but...

CF3Cl is chlorotrifluoromethane. Bond angle 109. Partial charges are delta + on C, delta - on everything else as Cl and F are more EN than C. It is polar as the centre of negativity =/= centre of positivity.
Iodine is used in making medicine.

The 2 intermolecular forces for the 2 pairs of molecules are Hydrogen bonding, and instantaneous dipole - induced dipole.

Iodine had 73.8% purity in the sample.

Carbon monoxide is toxic and oxidises to form CO2, a greenhouse gas

Ozone causes respiratory problems but it also blocks out high energy UV that would otherwise cause skin cancer.

I remember putting C20H30O + 5Br2 --> C20H30Br10O for the bromine one at the end. Colour change is red to colourless.
The reaction of propanone from propanol is redox I think
Propanone is propan-2-ol oxidised.

The evidence that greenhouse gases cause global warming is that there is a correlation between models of gas and models of temperature.

The bond that is most likely to break in CBrClF2 (?) is C-Br.

SiO2 is giant covalent and CO2 is simple molecular. The IM bonds of CO2 are weaker than the bonds in SiO2. So CO2 is a gas, and SiO2 is a solid.

Iodine is a grey solid at room temperature. Iodine's furthest sub shell is 5p5.
Chlorine's structure is 1s2,2s2,2p6,3s2,3p5.

The reagants and conditions for one of the reactions was phosphoric acid, steam, high temp. and pressure (300 C, 60 atm).

Reactions are slow in the atmosphere even though it has a low enthalpy as it is low pressure/concentration in the atmosphere.

The bond enthalpy of the water I think was 350kj/mol. Or something hundred and 50.

Ozone is naturally destroyed by UV and naturally created by UV homolytically splitting oxygen.

The primary alcohol molecules were retinol, ascorbic acid and fructose I think?

The reaction was a propagation reaction as there was a radical in the products and reactants.

(edited 9 years ago)

Reply 88

MMB07

1

were you asked to give the bond angle for the chlorotrifluoromethane shape question?

Reply 89

MasterOfTheSwag

1

Original post by MMB07

were you asked to give the bond angle for the chlorotrifluoromethane shape question?

Yes I am certain.

Reply 90

JammyGit07

16

What are people thinking will be the grade boundaries?

Reply 91

megannlizz

3

Original post by Maverick07

I put the reagent as silver nitrate and said that the Iodine might react with the silver instead forming AgI (yellow precipitate) instead of AgCl (white precipitate). I also got ethanoic acid for the acidic taste.

Posted from TSR Mobile

Ah yes i put that for the chlorine one too, i was unsure though

Reply 92

megannlizz

3

Original post by Kira Yagami

What did people put for the last question?! That question was so weird

Did any one get 0.03% for the impure sample of I...

Yeah i thought the last question was weird too, i wrote about the malalactic acid fermentation process and the polymerisation of flavanols. Ooh for the impure iodine i got something like 78.3%

Reply 93

megannlizz

3

Original post by Kira Yagami

Did people put propagation for the reaction?

Yes

Reply 94

Afro10

Original post by MasterOfTheSwag

Sorry about the order and lack of question numbers, and my answers may be wrong, but...

CF3Cl is chlorotrifluoromethane. Bond angle 109. Partial charges are delta + on C, delta - on everything else as Cl and F are more EN than C. It is polar as the centre of negativity =/= centre of positivity.
Iodine is used in making medicine.

The 2 intermolecular forces for the 2 pairs of molecules are Hydrogen bonding, and instantaneous dipole - induced dipole.

Iodine had 73.8% purity in the sample.

Carbon monoxide is toxic and oxidises to form CO2, a greenhouse gas

Ozone causes respiratory problems but it also blocks out high energy UV that would otherwise cause skin cancer.

I remember putting C20H30O + 5Br2 --> C20H30Br10O for the bromine one at the end. Colour change is red to colourless.
The reaction of propanone from propanol is redox I think
Propanone is propan-2-ol oxidised.

The evidence that greenhouse gases cause global warming is that there is a correlation between models of gas and models of temperature.

The bond that is most likely to break in CBrClF2 (?) is C-Br.

SiO2 is giant covalent and CO2 is simple molecular. The IM bonds of CO2 are weaker than the bonds in SiO2. So CO2 is a gas, and SiO2 is a solid.

Iodine is a grey solid at room temperature. Iodine's furthest sub shell is 5p5.
Chlorine's structure is 1s2,2s2,2p6,3s2,3p5.

The reagants and conditions for one of the reactions was phosphoric acid, steam, high temp. and pressure (300 C, 60 atm).

Reactions are slow in the atmosphere even though it has a low enthalpy as it is low pressure/concentration in the atmosphere.

The bond enthalpy of the water I think was 350kj/mol. Or something hundred and 50.

Ozone is naturally destroyed by UV and naturally created by UV homolytically splitting oxygen.

The primary alcohol molecules were retinol, ascorbic acid and fructose I think?

The reaction was a propagation reaction as there was a radical in the products and reactants.

If i put chloro-1,1,1-trifluoromethane would i still get the mark?

Reply 95

MasterOfTheSwag

1

Original post by Afro10

If i put chloro-1,1,1-trifluoromethane would i still get the mark?

I originally put 1-chloro-1,1,1-trifluoromethane, but I realised that had to be wrong. The fluorine couldn't be in any other position than where it already is, so the numbers are not necessary.
It really depends how lenient the mark scheme is. So it might say allow 1-chloro... or as it is one mark it might just say only chlorotrifluoromethane allowed. So I really don't know to be honest! It's only 1 mark anyway!

Reply 96

Deebernier

Original post by Afro10

If i put chloro-1,1,1-trifluoromethane would i still get the mark?

They can be really harsh about putting numbers in when they arent needed! I did a past paper and wrote ethan-1-ol and in the mark scheme it said not to accept it

Reply 97

Afro10

Original post by MasterOfTheSwag

I originally put 1-chloro-1,1,1-trifluoromethane, but I realised that had to be wrong. The fluorine couldn't be in any other position than where it already is, so the numbers are not necessary.
It really depends how lenient the mark scheme is. So it might say allow 1-chloro... or as it is one mark it might just say only chlorotrifluoromethane allowed. So I really don't know to be honest! It's only 1 mark anyway!