Chemistry Salters F332 june 2010Watch

8 years ago
#341
(Original post by Medicz)
N on Earth is 78%
Yep
0
8 years ago
#342
(Original post by maoam2406)
what did everyone get for the h/d ratio for % to ppm, i got 4 but everyone said that was wrong?!
I got a very small number.. something along the lines of.. 0.0014 ppm?
0
8 years ago
#343
On Earth the ratio of ordinary hydrogen to deuterium (H/D) is 1000 to 1.

That's what it says exactly.
0
8 years ago
#344
(Original post by Doctogan)
Sure you're right?

1000 hydrogen = 1 deuterium

So you divide the ppm by 1000?
Going back to GCSE, if you wanted to work out a certian amount of something and they were in ratios, you add the ratio numbers together, and then you get 1 part.

It's the same for this. So you would work out the ppm for this sample, and yoy get 1400. Then to get the amount of deutrium, you add 1000 and 1 together, and then divide this into 1400.
0
8 years ago
#345
I found this paper troubling and I was supposed to be one of the better candidates, too many places to lose marks with all the one and two markers, some of the questions were easy, many were strange, a few were identical to past ones, and the last six marker was the most I've ever waffled in a science exam, an despite that I can only count 3 relevant points in retrospect.
(I don't think we can talk specifically about it until 12 o'clock pm)
0
8 years ago
#346
The Mr times by the moldm^3.

That's right, no?
Yup, rearrange n=m/Mr
to get Mr x n = m
Sorted
0
8 years ago
#347
(Original post by cpdavis)
First part is correct, checked with teacher

For the second part, you had to use your own knowledge of the amount of Nitogen on earth(78%), The divide 3.5 by 78 to get the answer
Yeah, but the prerelease says Venus's atmosphere is 91 times as dense. (91 x 3.5)/78 = 4.1 So it has 4.1 times as much nitrogen. Pretty sure thats right? It was a 2 marker...
0
8 years ago
#348
(Original post by maoam2406)
what did everyone get for the h/d ratio for % to ppm, i got 4 but everyone said that was wrong?!
i thought it was just simply changing the percentage to ppm
i think it was 0.0018% to 18ppm
0
8 years ago
#349
(Original post by PotterLover)
Uh ohhh....
I just did 3.something divided by 78 X 100 ! I put 22 times more nitrogen....
SO DID I
0
8 years ago
#350
Found it a reasonable paper

For the oxidation state, what did you get for the second part
0
8 years ago
#351
(Original post by jetmanchandi)
i thought it was just simply changing the percentage to ppm
i think it was 0.0018% to 18ppm
i thought it was 0.0014% to 14ppm...

where did 18 come from?
0
8 years ago
#352
(Original post by Moe Lester)
Your meant to know it off by heart
Yeah :// I put 80, darn it. Someone told me it was written down! Liar
0
8 years ago
#353
(Original post by cpdavis)
Found it a reasonable paper

For the oxidation state, what did you get for the second part
I think I got 6
0
8 years ago
#354
sumit lyk dat, cnt remember the question lol
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8 years ago
#355
(Original post by jen vet)
Yeah, but the prerelease says Venus's atmosphere is 91 times as dense. (91 x 3.5)/78 = 4.1 So it has 4.1 times as much nitrogen. Pretty sure thats right? It was a 2 marker...
it probably is, darn it
0
8 years ago
#356
Ok.

Ah well. Just two marks. We'll see how it goes. No point worrying about it now. Hopefully the grade boundaries aren't too high!
0
8 years ago
#357
For PPM Deuterium in Water Vapour I got 0.028. There are 1 in 1000 Deuterium Atoms. 2 H's in Water, so therefore there is a 1 in 500 chance a water molecule will have a Deuterium Atom, hence why may answer is double most of yours.
0
8 years ago
#358
Not too bad, not too bad. Could have been much worse and there were no questions that I absolutely struggled 100% on. Thought a couple of questions were a bit vague though, reflux ones and CO2 absorption of IR.
0
8 years ago
#359
To go from mol dm-3 to g dm-3 don't u simply multiply by mr, as the units of mr are g/mol.
0
8 years ago
#360
Yeah :// I put 80, darn it. Someone told me it was written down! Liar
Meh, it was only two marks or something
0
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