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AQA Chemistry Unit 1 - [23rd May 2014]AM

June 2011 - 1cii: identify species responsible for peak at 64 - answer = 64Zn+ - why not Cu+ ? 63.5 is closer to 64 than 65.4?

you should have worked out that the relative atomic mass of the sample was 65.59, which is closest to 65.4, which is the ram of zinc- therefore all isotopes in the sample are isotopes of zinc

Reply 41

username702475

2

Original post by LookIts_Liam

you should have worked out that the relative atomic mass of the sample was 65.59, which is closest to 65.4, which is the ram of zinc- therefore all isotopes in the sample are isotopes of zinc

Ahhhh thank you :smile:

Reply 42

Nathan@

Do you have to draw the molecules in 3-D (with dotted lines etc.) ?

Reply 43

LookIts_Liam

10

Original post by Nathan@

Do you have to draw the molecules in 3-D (with dotted lines etc.) ?

it tends to say on the mark scheme that the exact shape doesn't matter, but i would draw it in 3d to be safe

Reply 44

Nathan@

Original post by LookIts_Liam

it tends to say on the mark scheme that the exact shape doesn't matter, but i would draw it in 3d to be safe

If you draw it in 3-D but incorrectly, for example, one drew a dotted line rather than a triangular line, would you lose the mark ?

Reply 45

LookIts_Liam

10

Original post by Nathan@

If you draw it in 3-D but incorrectly, for example, one drew a dotted line rather than a triangular line, would you lose the mark ?

no, as i said they always say shape doesnt matter, as long as you get the right number of bonding pairs, lone pairs, and then get the name of the shape and angle right (if they ask for them) it doesnt matter

Reply 46

Rooroo96

4

Original post by LookIts_Liam

no, as i said they always say shape doesnt matter, as long as you get the right number of bonding pairs, lone pairs, and then get the name of the shape and angle right (if they ask for them) it doesnt matter

Could they ask us about the really weird ones like T shape or the ones with double as well as single bonds such as NO3- and SO42-

Having a hard time trying to get my head around them tbh

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Reply 47

LookIts_Liam

10

Original post by Rooroo96

Could they ask us about the really weird ones like T shape or the ones with double as well as single bonds such as NO3- and SO42-

Having a hard time trying to get my head around them tbh

Posted from TSR Mobile

I'm not sure what T shape is - you need to know:

Linear - 2 bonding pairs, 180 degrees
Trigonal Planar - 3 bonding pairs, 120 deg
Tetrahedral - 4 bonding pairs - 109.5 deg
Trigonal pyramidal - 3 bp, 1 lone pair -107deg
Bent/vshaped -2bp, 2LP, 104.5 deg
trigonal bipyramidal - 5 bp - 90deg and 120deg
octahedral - 6bp - 90 deg

it doesnt really make a difference whether its double or single bond :smile:

Reply 48

Nathan@

Original post by LookIts_Liam

I'm not sure what T shape is - you need to know:

Linear - 2 bonding pairs, 180 degrees
Trigonal Planar - 3 bonding pairs, 120 deg
Tetrahedral - 4 bonding pairs - 109.5 deg
Trigonal pyramidal - 3 bp, 1 lone pair -107deg
Bent/vshaped -2bp, 2LP, 104.5 deg
trigonal bipyramidal - 5 bp - 90deg and 120deg
octahedral - 6bp - 90 deg

it doesnt really make a difference whether its double or single bond :smile:

Thanks, btw when writing equations are fractions or mixed numbers preferred and does your arrow have to drawn in a special way, like in unit 2 mechanisms etc.

Reply 49

safesploit

For bonding have a look at this website, it has a table on that is very easy to remember
http://www.thegeoexchange.org/chemistry/bonding/Molecular-Geometry/index.html

How the table works
AXN --> for example could be ammonia NH3 so
A= Nitrogen (Main bonding atom)
X= Hydrogen (bonding pair)
N= number lone pairs

Reply 50

LookIts_Liam

10

Original post by Nathan@

Thanks, btw when writing equations are fractions or mixed numbers preferred and does your arrow have to drawn in a special way, like in unit 2 mechanisms etc.

I would say mixed numbers in an equation, but again it doesn't matter...and when you draw the arrow, make sure it comes from the middle of the bond and is curvy

Reply 51

Lucy5000

Predictions of whats coming up?

Reply 52

Rooroo96

4

Original post by LookIts_Liam

I'm not sure what T shape is - you need to know:

Linear - 2 bonding pairs, 180 degrees
Trigonal Planar - 3 bonding pairs, 120 deg
Tetrahedral - 4 bonding pairs - 109.5 deg
Trigonal pyramidal - 3 bp, 1 lone pair -107deg
Bent/vshaped -2bp, 2LP, 104.5 deg
trigonal bipyramidal - 5 bp - 90deg and 120deg
octahedral - 6bp - 90 deg

it doesnt really make a difference whether its double or single bond :smile:

Hey thanks so much for that!! Much appreciated :biggrin:

T shape was in the Jan 2012 paper, qn 1, it's 3 BP and 2 LP but people generally aren't taught it

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Reply 53

f.igwe

Original post by Lucy5000

Predictions of whats coming up?

Litreally do soo many test papers you'll see the pattern

Reply 54

Reecelyons

Do people think either the exam will be easier or grade boundaries will be lower due to the lack of january exams, I feel that has been the case with Core 1 Maths and Physics 1.