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# Edexcel gcse chemistry- how did you find it?

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1. (Original post by caitlinford3)
0.7 - 0.42 to get 0.28 (mass of oxygen)

0.28 / 16 = 0.0175 (O)
0.42 / 24 = 0.0175 (Mg)
Then divide each by the smallest (but since they're the same just divide by themselves)
0.0175 / 0.0175 = 1 (O)
0.0175 / 0.0175 = 1 (Mg)
Ratio is therefore 1:1
So it's therefore MgO
yasss but how did you describe the experiment and stuff?
2. I wrote 1/1837 and I think that's right but they will accept 1/2000 as well

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3. (Original post by Heardmanator)
For the last one I talked about heating magnesium to get MgO and then did the empirical formula but because Oxygen is diatomic and they were all in the same ratio, you just had to multiply all of them by two to get 2Mg + O2 -> 2MgO to get the formula for it
4. (Original post by Penguin_S)
I wrote 1/1837 and I think that's right but they will accept 1/2000 as well

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anything below 1/5000 they will accept
5. (Original post by vik_k1)
I put 1/1837 as relative mass of an electron. Will I get a mark for that because apparently it's 1/2000???

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I put 1/1836
6. (Original post by caitlinford3)
oh???? then maybe i didn't lose 3 marks LOL
yeah because it just said 'a' experiment it didn't say like using a crucible or bell jar, like the C1 paper said when it said using "paraffin"
7. (Original post by KeziaKarunwi)
yasss but how did you describe the experiment and stuff?
I know I lost marks on this bit but I said about putting the magnesium ribbon, with the measured mass, in a bell jar and then measuring the mass after it had reacted with an unknown about of oxygen, then measuring the mass of the oxidised magnesium and from this working out the mass of oxygen. I know I lost marks though and that there was other ways of doing it!
8. (Original post by caitlinford3)
Yep I understand that it's MgO but oxygen doesn't just travel around by itself so there was O2 which meant you had to put a two in front of the MgO and the Mg to balance the equation
9. I got this for the pcl3 covalent bond question but my friend said that it was pcl2...? What did you guys get?
10. (Original post by caitlinford3)
I put 1/1836
i just said negligible i hope thats okay
11. (Original post by Penguin_S)
I got this for the pcl3 covalent bond question but my friend said that it was pcl2...? What did you guys get?
I got this too
12. (Original post by Penguin_S)
I got this for the pcl3 covalent bond question but my friend said that it was pcl2...? What did you guys get?
it was phosphorus trichloride, so three chlorines, so you were right
13. (Original post by chrlhyms)
yeah because it just said 'a' experiment it didn't say like using a crucible or bell jar, like the C1 paper said when it said using "paraffin"
very true, I just didn't realise my experiment was legit hahaha
14. (Original post by Penguin_S)
I got this for the pcl3 covalent bond question but my friend said that it was pcl2...? What did you guys get?
that's right its pcl3 - I didn;t draw the shells because my teacher taught us they were irrelevant but okay
15. I absolutely loved that exam! The to six markers were godsends I thought - the calculation questions were wonderful and I thought, in general, that paper was fantastic. So happy!
16. (Original post by caitlinford3)
Very easy, last 6 marker was weird
Easy???? :0
17. Is a period going down or across and what do you reckon it is for a C grade?
18. (Original post by caitlinford3)
I put 1/1836
I stated it exactly how it was in the revision guide - 1/1840. I did put in brackets underneath my answer 'negligible' as well though.
19. (Original post by Fez_Shabbir)
Is a period going down or across and what do you reckon it is for a C grade?
it goes down x
20. (Original post by Heardmanator)
Yep I understand that it's MgO but oxygen doesn't just travel around by itself so there was O2 which meant you had to put a two in front of the MgO and the Mg to balance the equation
Don't think so. Text book example is MgO

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