Ocr gateway CHEM 4 5 6 markscheme

How was it?? It was easy for me im taking it next year so im happy

Markscheme of my answers

C4

1) atomic mass-12 (6 protons add 6 neutrons)

Electrons or protons cant remember was 4 (mass takeway protons)

Configuration was 2.4 (6 electrons)
[3]

2) isotopes cause same atomic number but diff mass[3]

3)covalent bonds of cl and F should be two overlapping circles withh one pair of shared electrons[2]

4)mendeleev put elements on cards and arranged in ordee of properties and weight. Idea not accepted till gallium discovered[2]

5)iodide -grey solid astatine -320-340 allowance i think[2]

6)less reactive down group 7 because outer shell gets further away from nucleus so harder to gain electron[2]

7)[6]
it was copper chloride for compund A
because precipitate was blue with sodium hydroxide
compound B was iron (II) ...as precipitafe was green i think cant remember
Word equation forgot
Balanced equation forgot

8) super conductor used for medical scanners and powerful computers power transmission doesnt lose energy
Disadvantge expensive to maintain low cost doesnt work at room temp[3]

Missing question?

C5

1)number moles is 0.08[1]

2)use reacting ratios to get 50g[2]

3)i got 300 dm3 which is 300000cm3[2]

4) titrations [6 mark]
- ph starts high
-ph decreases when acid added
-ph decrease most near end point

Concentration was 0.16 mol/dm3 or 0.08

Volume was 40 cm3/ 20cm3 i wrote both just in case but i rhink 20

5) they use less acid(/alkali ???) of 0.05 so less moles
Graph would be lower than the first one lezs steep and reaction end slightly slower[2]
6)catalyst[1]
7)temp compromise balance betwwen yield and ratw increases rate of reaction

Catalyst- inrease rate not affect equilibrium

low Pressure cheap pressure affrcts yield[3]

8)concentration is how many moles of acid are dissolved in 1dm3
Strength is how much it ionises[2]

9) same volume produced cause same anount of reactants and concentration
[1]
10)high concentration of hydrochloric acid and more hydrofgen ionise s which increases frequency of collision
[2]
11)white is chloride, bromide is cream, iodide yellow precipitates so then y can work out what sample is which soz[3]

Total:25 marks

C6

[6 mark]
-oxidation is loss of electrons
-reduction is gain
-copper gaicn electrons to form Cu atom
-iron loses to form an iron ion
Word equations and balanced??

2)chlorine radical is regenerated so destroy more ozone it is a chain reaction[2]
3) O3------O2+.... reaction 4??[1]

4)prediction wrong because it only changed with soap nit the other one u had to be looking at water witb calcium hydrogen carbonate( temporary hardness)[2]

5)ester[1]
6) bromine water / addition reaction alkene decolourises etc cant remember his results[2]
7)margarine made from vegetable oil reacted with hydrogen and a catalyst
[2]
Section D

1) on grapb there was a decrease between 1977-1979 so thiys shows it was affecttive

2)nitroggen waterever this 88%

3)B more land more crops so more fertilser needed
4) for all residentual was smaller percentage

(edited 7 years ago)

Reply 1

Rjhepkenhdjd

2

found it p bad, but i just want a c (not doing it next year). totally forgot to revise redox n yikes

Reply 2

ellamoon_22

OP

3

Original post by Rjhepkenhdjd

found it p bad, but i just want a c (not doing it next year). totally forgot to revise redox n yikes

Sorry to hear this i hope u pass

(edited 7 years ago)

Reply 3

mxskaan

11

For the C4 6 marker it was copper chloride for compund A and compound B was iron (II) bromide.

For the C5 6 marker I got 0.08mol/dm3 of NaOH.

For C6 I got Fe + CuSO4 --> FeSO4 + Cu. Fe oxidised. Cu reduced.

Posted from TSR Mobile

(edited 7 years ago)

Reply 4

esmithxx

13

Not too bad I thought the 6 markers were okay

Reply 5

esmithxx

13

Original post by mxskaan

For the C4 6 marker it was copper chloride for compund A and compound B was iron (II) bromide.

Posted from TSR Mobile

I got that!

Reply 6

jaisuf

13

Hated the first two 6 markers and a few other questions sucked. Meh, it was okay overall I guess.

Reply 7

esmithxx

13

Original post by ellamoon_22

How was it?? It was easy for me im taking it next year so im happy

Markscheme of my answers

C4
1) atomic mass-12 (6 protons add 6 neutrons)

Electrons or protons cant remember was 4 (mass takeway protons)

Configuration was 2.4 (6 electrons)

2) isotopes cause same atomic number but diff mass

3)covalent bonds of cl and F should be two overlapping circles withh one pair of shared electrons

4)mendeleev put elements on cards and arranged in ordee of properties and weight. Idea not accepted till gallium discovered

5)iodide -grey solid astatine -320-340 allowance i think

6)less reactive down group 7 because outer shell gets further away from nucleus so harder to gain electron

7)6 mark
-A was copper because precipitate was blue with sodium hydroxide
B was iron 11 as precipitafe was green i think cant remember
Word equation forgot
Balanced equation forgot

8) super conductor used for medical scanners and powerful computers power transmission doesnt lose energy
Disadvantge expensive to maintain low cost

I put the disadvantage was that they can't work at room temp so special equipment is needed

Reply 8

robyn2000

2

For the properties of the simple molecular substance (I think it was chlorine fluorine?) I put low boiling point, likely to be a gas at room temperature and does not conduct electricity
0.08mol/dm3 for the concentration question

Reply 9

Rjhepkenhdjd

2

was the first question to do w the table bc ahh i completely missed it?? do you know how many marks it was worth sorry?

Reply 10

leopard923

11

Original post by mxskaan

For the C4 6 marker it was copper chloride for compund A and compound B was iron (II) bromide.

For the C5 6 marker I got 0.08mol/dm3 of NaOH.

For C6 I got Fe + CuSO4 --> FeSO4 + Cu. Fe oxidised. Cu reduced.

Posted from TSR Mobile

Same!

Posted from TSR Mobile

Reply 11

leopard923

11

Original post by Rjhepkenhdjd

was the first question to do w the table bc ahh i completely missed it?? do you know how many marks it was worth sorry?

3 marks

Posted from TSR Mobile

Reply 12

robyn2000

2

Original post by Rjhepkenhdjd

was the first question to do w the table bc ahh i completely missed it?? do you know how many marks it was worth sorry?

I believe 2 or 3? I have done this so many times!

Reply 13

ellamoon_22

OP

3

Keep refreshing guys :h:

Reply 14

United2810

13

I'm the only one I think in my school to find that exam not hard. Like I struggled with the first 6 marker and a couple of other questions but I finished the whole paper with 30 mins to spare, the fact that there was no electrolysis either. Everyone else came out and said they've failed that exam but I think I've done well, apart from the first 6 marker which I just couldn't remember how to do. Counted up my definite marks and it came to about 55 so I should be nailed on for an A, probably an A*.

Grade boundaries will decrease because I think the paper was harder than last years, so it'l go down to about 56-58?