You are Here: Home

Ocr gateway CHEM 4 5 6 markscheme

Announcements Posted on
Last day to win £100 of Amazon vouchers - don't miss out! Take our quick survey to enter 24-10-2016
1. Normally high 50s/low60s range dependent on difficulty

Posted from TSR Mobile
2. (Original post by Meganward123)
can someone please explain the concentration 6 marker?
I worked out that there were 0.0025 moles, 0.0025/(20/1000) equals 0.125 mol/dm3
I used the equation- Volume (acid) x Concentration (acid)= Volume (alkali) x Concentration (alkali)
3. 1920 cm^ 3 for the volume question using 24000cm3

0.08 moles

0.08 was the conc of sodium hydroxide in the 6 marker at 20 cm was the end point
4. (Original post by Swagswag1963)
1920 cm^ 3 for the volume question using 24000cm3

0.08 moles

0.08 was the conc of sodium hydroxide in the 6 marker at 20 cm was the end point
Yes I agree.

Posted from TSR Mobile
5. (Original post by Rjhepkenhdjd)
do you know what the grade boundaries for it are normally like in general? ty !!
Going off last year, it was 60 for an a*, 50 for an A, decreasing each time by 10 marks.
C1,2,3 was 61 for an A*
6. (Original post by Meganward123)
can someone please explain the concentration 6 marker?
I worked out that there were 0.0025 moles, 0.0025/(20/1000) equals 0.125 mol/dm3
concentration of acid x volume acid = concentration of alkali x volume alkali

This is the equation u use for titrations.

So u fill it in

0.1*40=?* 25

?= (0.1*40)/25
7. (Original post by esmithxx)
I used the equation- Volume (acid) x Concentration (acid)= Volume (alkali) x Concentration (alkali)
Thanks Emily!
8. (Original post by Meganward123)
can someone please explain the concentration 6 marker?
I worked out that there were 0.0025 moles, 0.0025/(20/1000) equals 0.125 mol/dm3
I did it like so:
Moles = concentration*volume
Moles HCl = 0.1 * 20/1000 (convert to dm3) = 0.002

HCl:NaOH
1:1
0.002:0.002

Concentration = moles/volume
Concentration NaOH = 0.002/(25/1000)
= 0.002/0.025 = 0.08

Posted from TSR Mobile
9. what was the answer to how much pesticide was used for country E
10. (Original post by JickDee)
what was the answer to how much pesticide was used for country E
1,260,000,000 ???

Posted from TSR Mobile
11. (Original post by mxskaan)
1,260,000,000 ???

Posted from TSR Mobile
Didn't you have to multiply that by 0.18
12. (Original post by mxskaan)
1,260,000,000 ???

Posted from TSR Mobile
I got something like that too
13. (Original post by happiness12)
I got something like that too
14. (Original post by ellamoon_22)
I got 0.16 for the titration six marker
15. (Original post by ellamoon_22)
Didn't you have to multiply that by 0.18
16. (Original post by haithamnhaque)
I got 0.16 for the titration six marker
It was 0.08
17. (Original post by haithamnhaque)
I got 0.16 for the titration six marker
Sme bit everyone sed end point was 20 idk
18. What was the answer to the question where it asked what mass would be produced with 20.6 amps instead of 10.3 for 120 minutes ???
i got 60 g
19. (Original post by ellamoon_22)
I just read the titration page and you are supposed to use the point of neutralization. That means it is not 0.16
20. (Original post by happiness12)
What was the answer to the question where it asked what mass would be produced with 20.6 amps instead of 10.3 for 120 minutes ???
i got 60 g
Yeah I think I got that too.

Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: June 21, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:

How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources