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AQA AS Chemistry unit 1 resit May 27th 2016

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Original post by A2LEVELSHELPME
Anyone here doing CHEM2 as well?


yea
for mass spec similarities, did anyone write same molecular ion peak due to same Ar of sample?
Original post by Ultracrepidarian
what mr did you use do you remember what it was


No, do you remember what the formula was
What was the answer to the detection question. Q1b
When drawing the 3 isomers
Position- just change the double bond so it's on a different carbon
Functional group - change it from an alkene to n alkane, remove the double c bond
What about for chain isomerism?
Original post by RME11
The conc & vol of the solution was 5moldm-3 & 3m3, You had to change the 3m3 into dm3 first so you ended up with 3000dm3

moles = conc X vol = 5*3000 = 15,000 moles h3po4

Ratio P4O10 to H3PO4 was 1:4 therefore 15000 moles h3po4 = 3750 moles P4O10

Mass = moles * mr = 3750 * ((31*4)+(10*16)) = 1065000g = 1065KG.


i did all of that :/ must have typed it in wrong hopefully i will still get method marks
Original post by selena0101
What was the answer to the detection question. Q1b


Magnetic field?
Original post by Matt Johnson
When drawing the 3 isomers
Position- just change the double bond so it's on a different carbon
Functional group - change it from an alkene to n alkane, remove the double c bond
What about for chain isomerism?


For chain isomerism i got 2-methylprop-1-ene
Original post by A2LEVELSHELPME
Anyone here doing CHEM2 as well?


Yep I am :smile:
Original post by Bailey2j09
No, do you remember what the formula was


i think i typed it into my calculator wrong but hopefully get method marks
2,2,3-trimethypentane anyone?
Reply 271
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Original post by Charco63
0.451/0.453 m3 but not sure that is right, checked it over and over and couldn't see why not

And mass of 1065000 something grams


this is exactly what i got as well!
What was the bond angles for SF4? I know the shape, I put 117.5 and 87.5 for bond angles because you minus 2.5 per line pair. But I'm not sure if you do it for both bond angles of it you split it between them .
Reply 273
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Original post by Batmansdad
2,2,3-trimethypentane anyone?


yes x
For the Shapes of Molecules qs, SF4 has 4 bonding pairs and 1 lone pair - take the assumption that you took a trigonal bipyramidal but then put a lone pair on it, the bond angles on the trigonal bipyramidal is 90, 120 degrees and its cut by 2/2.5° so you should take 88 and 118°
Reply 275
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Original post by emsieMC
What was the bond angles for SF4? I know the shape, I put 117.5 and 87.5 for bond angles because you minus 2.5 per line pair. But I'm not sure if you do it for both bond angles of it you split it between them .


its 90 as its a trigonal bypyramid and the lone pair is opposite the T shape or maybe 120
(edited 7 years ago)
Also dos anyone get oxygen for that which element ionisation number thing? I can't remember is it was period 3 or 2 and I'm shitting myself in case it's sulphur instead, as it was the 7th ionisation energy right?
Original post by Matt Johnson
When drawing the 3 isomers
Position- just change the double bond so it's on a different Carbon
Functional group - change it from an alkene to n alkane, remove the double c bond
What about for chain isomerism?


For functional group it has to be cyclobutane and yeah for chain it's methylpropene
Original post by Matt Johnson
When drawing the 3 isomers
Position- just change the double bond so it's on a different carbon
Functional group - change it from an alkene to n alkane, remove the double c bond
What about for chain isomerism?


Chain: 2-Methylpropene
Position: But-2-ene
Functional gr: Cyclobutane
Original post by User2334541
For the Shapes of Molecules qs, SF4 has 4 bonding pairs and 1 lone pair - take the assumption that you took a trigonal bipyramidal but then put a lone pair on it, the bond angles on the trigonal bipyramidal is 90, 120 degrees and its cut by 2/2.5° so you should take 88 and 118°

So....I got it right? yay! I wasn't sure because I know the shape and it only had one electron pair, but I didn't know if it affected both angles by 2.5/2.

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