Chemistry practical OCR AS Watch

This discussion is closed.
Sezzie69
Badges: 0
#61
Report 13 years ago
#61
(Original post by mini me)
did it actually ask you to name the indicator? i thought you just had to say the result! :s
Yeah it did ask you to name the indicator u used!! what did u use, maybe it wont matter. we used universal indicator solution. Except one of my mates put it into the rong test tube, she put it in the HCl so it didnt do here any favours! lol i felt so bad for her
when i put my CaCO3 in with the HCl it went every where and then it wouldnt work so i had to add more acid!
then i burnt myself on the bunsen! ouch :eek: lol. ahh well, they are all in the past now, hope everyone did good!! xx Sezzie69 xx
0
shyopstv
Badges: 2
Rep:
?
#62
Report 13 years ago
#62
(Original post by Sezzie69)
then i burnt myself on the bunsen! ouch :eek: lol.
lol someone in my class managed to burn his exam paper. Not entreily sure if it was accidental or not
0
-sophie-
Badges: 2
Rep:
?
#63
Report 13 years ago
#63
I got 4 damn it i used mmr of water to b 44 aswell ooooops i hope i dont loose a tonne of marks
0
-sophie-
Badges: 2
Rep:
?
#64
Report 13 years ago
#64
i mean 33 oops i am scatty!!!!
0
-sophie-
Badges: 2
Rep:
?
#65
Report 13 years ago
#65
Im worried now!!!!
0
ben!
Badges: 1
Rep:
?
#66
Report 13 years ago
#66
(Original post by brianfall)
Calcium sulphate is CaSO4 - unfortunately I put CaSO3 :-(

I got 7 moles of water like so;

1.04g MgSO4 = 1.04/ (24.3 + 32.1 = (16 * 4)) = 1.04/120.4 = 0.008638 moles
1.11g H20 = 1/18 = 0.0617 moles

So moles of water in 1 mole of MgSO4 = 0.0617/0.008638 = 7.1429 moles

Anyone know if this looks right?
Thats more or less what I got, certainly the 1:7 ratio seems to be what people came up with I didnt think it was too bad, compared with the previous papers I'd looked at it seemed quite friendly. Liked the improved layout of the evaluation sections as well, much easier to complete!
0
coldfusion
Badges: 2
Rep:
?
#67
Report 13 years ago
#67
Our scale was wrong. It was measuring in calories (no clue what it was) so half the class lost all the accuracy marks for part 1 (about 8)
0
Just Grow up
Badges: 0
#68
Report 13 years ago
#68
I thought it was ok, even my teacher says it's easy, er...compare to biology I think it's much easier, hate that biology practical from the heart
My ratio was 1:7 too
0
JimmE
Badges: 0
#69
Report 13 years ago
#69
Yes, I got 7 moles of Water of Crystallisation, same as my teacher. Z was limewater (Calcium Hydroxide, Ca(OH)2) and insoluble substance was Calcium Sulphate (CaSO4) which prevented the H2SO4 from reacting with the CaCO3.

An excellent practical, i thought, through for me it was a re-take (i'm year 13)
0
tozhan
Badges: 0
Rep:
?
#70
Report 13 years ago
#70
ok, what was the reason o for letting the crucible cool before weighing it?!

i could only think of: avoiding burns to yourself and damaging the balance...was there a chemical reason? it was a chemistry exam after all...
0
Aired
Badges: 1
Rep:
?
#71
Report 13 years ago
#71
(Original post by tozhan)
ok, what was the reason o for letting the crucible cool before weighing it?!

i could only think of: avoiding burns to yourself and damaging the balance...was there a chemical reason? it was a chemistry exam after all...
If you place a hot object on an electronic balance, the convection caused by the warm object can cause an innacurate reading.
0
brianfall
Badges: 0
#72
Report 13 years ago
#72
(Original post by tozhan)
ok, what was the reason o for letting the crucible cool before weighing it?!

i could only think of: avoiding burns to yourself and damaging the balance...was there a chemical reason? it was a chemistry exam after all...
Apparently hot substances cause convection currents which affect the accuracy of the scales. If you put something hot on the scales it's like trying to use them in a draft and the scales flicker. This definitely wasn't on the syllabus so I think the two other things you said should have both got you a mark.
0
brianfall
Badges: 0
#73
Report 13 years ago
#73
ahhh spooky - we must both have posted at the same time!
0
tozhan
Badges: 0
Rep:
?
#74
Report 13 years ago
#74
lol, i stick to the damn syllabus so that was totally unfair! bloody examiners.
0
X
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • University of the West of England, Bristol
    Undergraduate Open Afternoon - Frenchay Campus Undergraduate
    Wed, 23 Jan '19
  • University of East London
    Postgraduate Open Evening Postgraduate
    Wed, 23 Jan '19
  • University of Gloucestershire
    School of Education Open Day Postgraduate
    Wed, 23 Jan '19

Brexit: Given the chance now, would you vote leave or remain?

Remain (1647)
78.77%
Leave (444)
21.23%

Watched Threads

View All