Official AQA AS Chemistry Unit 1 - 23Rd May 2013

You'd use the carbon that's closest to the additional group. For example, instead of using '3-methylbutane' (as it might look), you'd use '2-methylbutane'.
This also applies to double bonds..
Instead of 'but-3-ene' it would be 'but-1-ene' :smile:

(edited 10 years ago)

Reply 21

tumblrgirl

ah right, thanks both of you :smile:

Reply 22

username984585

20

This exam has come around so soon!

Those of you who did the Jan 2013 paper, how did you find it? :smile:

This will be my first and hopefully last sitting of the paper.

Reply 23

tumblrgirl

Original post by Octahedral

Take this for example

You would deduce which way you look at it gives you the smallest number on the carbon chain, from left to right it would be 4,4-DiChloro-3-MethylPentane. You then would look at it from the other way (right to left) and it would be 2,2-DiChloro-3-MethylPentane.
As you can see the position of the functional groups on the 2nd Haloalkane is lower than the 1st Haloalkane so that would be it.
Hope this makes sense.

Anybody help me with this?
i)Write an equation to show how NO is formed and give a condition needed for its formation[2]
ii) Deduce an equation to show how NO2 reacts with H20 & O2 to form HNO3[1]

not sure about part i) but for part ii) 4NO2 +2H2O + O2 -> 4HNO3 :smile:

Reply 24

nawal

4

Original post by Nav_Mallhi

This exam has come around so soon!

Those of you who did the Jan 2013 paper, how did you find it? :smile:

This will be my first and hopefully last sitting of the paper.

I found it really hard :frown:

Reply 25

SonamH

Original post by Nav_Mallhi

This exam has come around so soon!

Those of you who did the Jan 2013 paper, how did you find it? :smile:

This will be my first and hopefully last sitting of the paper.

I done the Jan 2013 paper as a mock, it was quite easy tbh..not so great for us then :/

Reply 26

SonamH

Jan 2013 paper and mark scheme for anyone who wants it

https://www.dropbox.com/sh/4m2j1fye6mpcvbz/PlhQvakB_z

Reply 27

tumblrgirl

i get really confused with bond angles, i'm alright with drawing them out but when it asks you to predict the bond angle, I never know what it is :s help :frown:

Reply 28

SonamH

Original post by tumblrgirl

i get really confused with bond angles, i'm alright with drawing them out but when it asks you to predict the bond angle, I never know what it is :s help :frown:

Just remember that the bond angle in a tetrahedral shape is 109.5 and each lone pair reduces the angle by 2.5 so for example a trigonal pyramidal shape has 3 bonded pairs and 1 lone pair so 109.5 - 2.5 = 107 which is the bond angle in the trigonal pyramidal shape. Hopefully that makes sense

Reply 29

dakenSoren

2

Here is all of my Unit 1 notes. Most of it is pretty personalised and may have random things or tangents I went into. Also a lot is paraphrased from the book. :smile:

Chem unit 1.docx794.5KB

Reply 30

tumblrgirl

Original post by SonamH

Just remember that the bond angle in a tetrahedral shape is 109.5 and each lone pair reduces the angle by 2.5 so for example a trigonal pyramidal shape has 3 bonded pairs and 1 lone pair so 109.5 - 2.5 = 107 which is the bond angle in the trigonal pyramidal shape. Hopefully that makes sense

thank you

Reply 31

Niamh5445

Original post by tumblrgirl

not sure about part i) but for part ii) 4NO2 +2H2O + O2 -> 4HNO3 :smile:

for part i) you have Nitrogen and Oxygen in an engine so the reaction is 1/2 N2 + 1/2 O2 -> NO or you can have a whole number equation of N2 + O2 -> 2NO and you need a high temperature or a spark for this reaction to occur.

Reply 32

MOOOSEH

7

Does anyone else have problems with general calculations? D: Amounts of Substance? Any resource to help strengthen this area since I seem to be okay with the straightforward ones but as they add more steps I get extremely confused.
Also when they give you for example, and eqtn and they'd ask how much the concentration would be for 1 mole of blah blah substance D:

I wish I could elaborate further.
Any assistance please?

Reply 33

mynameisntbobk

18

Original post by Nav_Mallhi

This exam has come around so soon!

Those of you who did the Jan 2013 paper, how did you find it? :smile:

This will be my first and hopefully last sitting of the paper.

I sat the Jan exam and got an A, so anyone, feel free to ask questions while you still have the chance, I'll be happy to help, just glad I don't have to sit it again

Reply 34

meenod

Original post by tumblrgirl

so I came across this question in Jan12 paper and I got a completely different answer from the markscheme on what the name of it is...
the markscheme says it's called 2,2 dichloro 3 methyl pentane....i don't understand why, anyone wanna help me? :smile:

I always get super confused by these!!
I find it really helpful to fully draw out the displayed formula if you're stuck, it makes it easier to see methyl groups

Reply 35

Qaiser123456

Hello there everyone I want to say good luck to everyone epically to my friend umar and Ahmed and Minaan(snowman)

Reply 36

Qaiser123456

Hello there every one I want to say good luck to everyone epically my friend umar and Ahmed and Minaan(snowman)

Reply 37

chelley2

Original post by mynameisntbobk

I sat the Jan exam and got an A, so anyone, feel free to ask questions while you still have the chance, I'll be happy to help, just glad I don't have to sit it again

You Beast!! .I found it extremely hard especially the last questions.There were alot of calculations on that paper ,it put me off.
I've got a question.When working out bond angles of ions when it's a positively charged ion does that mean the central atom has lost an electron so you don't include that electron in the shape .When its a negative charge an electron has been gained.ahh I'm so confused :/
Thanks in advance :smile:

Posted from TSR Mobile

Reply 38

username984585

20

Original post by mynameisntbobk

I sat the Jan exam and got an A, so anyone, feel free to ask questions while you still have the chance, I'll be happy to help, just glad I don't have to sit it again

That is very sweet of you. :smile:

And well done for the A!

Reply 39

mynameisntbobk

18

Original post by chelley2

You Beast!! .I found it extremely hard especially the last questions.There were alot of calculations on that paper ,it put me off.
I've got a question.When working out bond angles of ions when it's a positively charged ion does that mean the central atom has lost an electron so you don't include that electron in the shape .When its a negative charge an electron has been gained.ahh I'm so confused :/
Thanks in advance :smile:

Posted from TSR Mobile

Haha thank you :smile:

it was definitely a hard exam, so I was actually surprised I got the grade I did, I lost most of my marks in the calculations though :tongue:

and a few in question 1 and 2

And yep, you got the completely right, if its positive, the central atom has lost an electron, so its not included in the shape, vice versa for negative charge :smile:

Official AQA AS Chemistry Unit 1 - 23Rd May 2013

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