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Edexcel Chemistry Unit 1 (23/05/2013)

Hiii couldn't find a thread for this exam so I created this one.
Does anybody have the question paper and mark scheme for the Jan 2013 unit 1 exam ??

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Reply 1
Avatar for mary05
mary05
Yeah I do


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Reply 2
Avatar for Cerdic
Cerdic
18
Original post by Ifa_94
Hiii couldn't find a thread for this exam so I created this one.
Does anybody have the question paper and mark scheme for the Jan 2013 unit 1 exam ??


As per usual, Free Exam Papers does. I've attached it for convenience
6CH01_01_que_20130110.pdf486.9KB
Reply 3
Avatar for Ifa_94
Ifa_94
OP
Original post by adi19956
As per usual, Free Exam Papers does. I've attached it for convenience


Thank You so much!!
Reply 4
Avatar for kevsamuel
kevsamuel
Is this everyone's first time or are they resitting it? I'm resitting it as I got a C in January...hopefully I'll get an A this time round!
Reply 5
Avatar for felicity95
felicity95
Hi guys. I sat this paper in January and failed :frown: It was awful compared to past papers. There were some stupid mc questions and I was wondering if anyone could help explain this one to me. Apparently the answer is A (z+4 neutrons) but how if neutrons = mass number - atomic number then surely 2z+4 - z is not z + 4.

Im very bad at maths so it might just be me :biggrin:

An isotope of an element, atomic number z, has mass number 2z + 4. How many
neutrons are in the nucleus of the element?
A z + 4
B z + 2
C z
D 4
Reply 6
Avatar for kevsamuel
kevsamuel
Original post by felicity95
Hi guys. I sat this paper in January and failed :frown: It was awful compared to past papers. There were some stupid mc questions and I was wondering if anyone could help explain this one to me. Apparently the answer is A (z+4 neutrons) but how if neutrons = mass number - atomic number then surely 2z+4 - z is not z + 4.

Im very bad at maths so it might just be me :biggrin:

An isotope of an element, atomic number z, has mass number 2z + 4. How many
neutrons are in the nucleus of the element?
A z + 4
B z + 2
C z
D 4



Well firstly an isotope has the same number of protons but different number of neutrons. Replace z for any number i.e 6 and since z is the atomic number this element would be Carbon. then it says it has mass number 2z + 4, so when you replace z with 6 you get 16. and 16 is 4 more than 12 (which is Carbon's mass number) so it must be z + 4.

Hope this helped :smile:
Reply 7
Avatar for felicity95
felicity95
Original post by kevsamuel
Well firstly an isotope has the same number of protons but different number of neutrons. Replace z for any number i.e 6 and since z is the atomic number this element would be Carbon. then it says it has mass number 2z + 4, so when you replace z with 6 you get 16. and 16 is 4 more than 12 (which is Carbon's mass number) so it must be z + 4.

Hope this helped :smile:


Thank you! much better :biggrin: x
Reply 8
Avatar for acer0951
acer0951
14
Original post by kevsamuel
Well firstly an isotope has the same number of protons but different number of neutrons. Replace z for any number i.e 6 and since z is the atomic number this element would be Carbon. then it says it has mass number 2z + 4, so when you replace z with 6 you get 16. and 16 is 4 more than 12 (which is Carbon's mass number) so it must be z + 4.

Hope this helped :smile:


Very well explained! I was having the same problem. Thanks


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Reply 9
Avatar for jemma01
jemma01
Hi guys
I was just wondering if someone could tell me how to answer the multiple choice questions when it asks you to work out the number of moles of a substance and gives you the Avogadro constant?
Original post by jemma01
Hi guys
I was just wondering if someone could tell me how to answer the multiple choice questions when it asks you to work out the number of moles of a substance and gives you the Avogadro constant?


You work it out using:
Moles= no. of particles /Avogadro constant

then tick the box with the answer that matches yours (sorry, couldn't resist) .
Be on the lookout for whether they have given you atoms or molecules to work with.
Reply 11
Avatar for Jayqwe
Jayqwe
1
If you want the January 2013 question paper and mark sheet, here they are:
Jan 2013 Chem Unit 1 QP.pdf477.9KB
Jan 2013 Chem Unit 1 MS.pdf251.3KB
Reply 12
Avatar for Mollymod
Mollymod
15
Original post by kevsamuel
Is this everyone's first time or are they resitting it? I'm resitting it as I got a C in January...hopefully I'll get an A this time round!


I'm a resitter, simply to boost up my grade for A2.
I'm doing Unit 5 in a month too, so Unit 1 is a good like memory jogger.
I really need full UMS in this if I want an A, so it's a tight margin.

Any questions, you can ask me and I'll do my best to try and answer them :smile:
I'm resitting too :smile:

Will be starting revision tomorrow for this... I need as many UMS as I can get :frown: As at the moment I'm on a D & need a B !

But still it's good practice anyway I guess :smile: I hope this thread become more active!

Good luck with revision everyone !
Reply 14
Avatar for mnasmith
mnasmith
got 77 marks in jan dont know why im resitting lol
Reply 15
Avatar for mary05
mary05
Are u serious


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Reply 16
Avatar for jemma01
jemma01
Original post by Pirateprincess
You work it out using:
Moles= no. of particles /Avogadro constant

then tick the box with the answer that matches yours (sorry, couldn't resist) .
Be on the lookout for whether they have given you atoms or molecules to work with.


Thanks!
Reply 17
Avatar for felicity95
felicity95
Hi :smile:

In January there was this question on bond enthalpies and can someone please explain how you calculate them. I always thought you multiply each value by the amount of that type of bond e.g. for C2H6 there would be 6 x C-H bond. Ive attached the question and answer so id appreciate any help. thanks :smile:
chem question.png16.4KB
answer.png29.6KB
Reply 18
Avatar for Jayqwe
Jayqwe
1
Original post by felicity95
Hi :smile:

In January there was this question on bond enthalpies and can someone please explain how you calculate them. I always thought you multiply each value by the amount of that type of bond e.g. for C2H6 there would be 6 x C-H bond. Ive attached the question and answer so id appreciate any help. thanks :smile:


You were on the right track, so you just need to follow up on it.
On the left hand side (LHS), you have 6 C-H bonds and 1 Cl-Cl bond which equates to-> 6(413)+243
On the RHS, you have 5 C-H bonds, 1 C-Cl bond, and 1 H-Cl bond which equals to-> 5(413)+346+432
LHS=2721
RHS=2843
Enthalpy Change=LHS-RHS
2721-2843=-122 kJ mol^-1
Reply 19
Avatar for Mollymod
Mollymod
15
Original post by felicity95
Hi :smile:

In January there was this question on bond enthalpies and can someone please explain how you calculate them. I always thought you multiply each value by the amount of that type of bond e.g. for C2H6 there would be 6 x C-H bond. Ive attached the question and answer so id appreciate any help. thanks :smile:


Bonds broken subtract bonds made.
It's an exothermic energy change, so

You're right for the 6 x C-H bond which equals 2478 KJmol-1
Then 243 for the Cl-Cl bond KJmol-1

The sum of these is 2721.

On the products side it's 5 x 413 = 2065 KJmol-1
+346 + 432 = 2843 KJmol-1

Then, we do 2843 - 2721 = 122 KJmol-1

It's an exothermic energy change because more more energy is used to break bonds, than make the bonds, so we change the sign to -, so it's -122 KJmol-1
(edited 10 years ago)

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