The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

Edexcel Chemistry IGCSE 1C Unofficial Mark Scheme 19th May 2016

Scroll to see replies

Original post by conradliebers
Tell me the questions which I'm missing out - I'll add them in. Please try your best to remember the rough question number. Thanks for all the contributions, including the desperate Advait10.



Wait, wasn't the answer to the chormatography question '3' because the fourth one at the bottom was the original spot of dye???
Original post by Robertarthur
I agree with Pedaly7, it was a double bond so CH2 couldn't possible exist


Yes, but it is only the 'theoretical' ratio of the elements. Surely they wouldn't specify it being the empirical formula if all you had to do was right the molecular formula straight off the sheet.
Reply 302
Avatar for VinuJ
VinuJ
9
Yeah it's definitely CH2, the simplest form = empirical formula and up to GCSE it doesn't matter whether its not practical you just right it down haha
Original post by asd.987
Wait, wasn't the answer to the chormatography question '3' because the fourth one at the bottom was the original spot of dye???


No it wasn't, it was slightly above the line.
Original post by jamesj477
You'll only get 1 for that I think. Whilst its correct, it asked for physical things you could see which are
-effervescence / fizzing
-calcium floats on water and moves around
-calcium disappears / ppt formed

For this question I wrote that it will fizz, and it will form an alkaline solution. Do you know how many marks this would get me?
Reply 305
Avatar for jjg456
jjg456
Question on why water and solution y was used to clean out burette with solution X previously in it?
Original post by lucyjohnson82
For this question I wrote that it will fizz, and it will form an alkaline solution. Do you know how many marks this would get me?

1 mark for fizz, no marks for alkaline solution I'm afraid as it asked for "observations". One cannot observe a change in pH.
For the metal reactivity question do we have to put the temperature or temperature rise by minusing with 25
It asked the temperature rise so minus 23 from the answer- so should get 10
Original post by Legend991
nah it was 0.75


nah it was 0.9
the formula of hydrated copper sulphate in the question was CuSO4.5H2O
The starting mass of copper sulphate was 2.5g, the Mr of CUSO4.5H2O is 250.
Moles = mass/mr (2.5/250)
moles = 0.01

There were 5x the amount of moles of water
moles of water = 5 x 0.01= = 0.05
the mr of water is 18
0.05 x 18 = 0.9g

Theres also another way of doing it that involves finding the percentage of water in hydrated copper sulphate, then finding that percentage of 2.5, which also gave 0.9g
hi i believe i got 85 in that paper. what grade is that

Posted from TSR Mobile
Original post by Hsevras
hi i believe i got 85 in that paper. what grade is that

Posted from TSR Mobile


It depends what you get in the next paper, theres no point calculating individual grades for each paper. The maximum possible grade you can get now is 145/180, if you get 100% in paper 2. Thats in the area of the A/A* grade boundary, which varies from about 135-145. However this paper was easier than the others, so I think the grade boundary will be somewhere in the 140's.
Original post by dance25
Lol at least you didn't just right magnesium 💁🏽 ahaah when will I learn to read the question


Posted from TSR Mobile


no you are thinking of the wrong question! one of them said which had the biggest increase and another later on asked what the great increase was.... if you wrote magnesium for an answer you are right!
Original post by tmg1999
no you are thinking of the wrong question! one of them said which had the biggest increase and another later on asked what the great increase was.... if you wrote magnesium for an answer you are right!


Oh lol haha thanks 😂🙏🏾


Posted from TSR Mobile
u forgot a question at the end of 3 about the predicted formula of an ionic compound( can't remember the letters). It was something like suggest the formula of the ionic compound formed between elements A and B
Reply 315
Avatar for Nurne
Nurne
2
Question 14 Potassium Hydrogencarbonate

0.08 KHCO3
0.06 K20
0.10 KOH
0.04 Don't remember the salt
For the table

Then equation 3, because ratio is 2:1 and the mole ratio for the hydrogencarbonate 2:1 (0.08-> 0.04)
i and almost all my friends got 0.9 for that water mass...

Original post by M12345678
u forgot a question at the end of 3 about the predicted formula of an ionic compound( can't remember the letters). It was something like suggest the formula of the ionic compound formed between elements A and B
was not that H2O?
Original post by Abodee1
i and almost all my friends got 0.9 for that water mass...

was not that H2O?


I think, if my memory serves me right, that A had only 1 electron so would be hydrogen and D had two shells and six valence electrons, so H2O would form as the compound of the two
For 9b you were already given that rate of forward reaction= rate of backwards reaction- you had to write another (has to take place in a closed system etc)
No, in the question, u were given nothing about RATE, they told u just that they are happening at the same time ("simultaneously ")

Posted from TSR Mobile

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you