Sorry wasn't able to log on here
How did u do ?
-
We need your support!
We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
Click here to Donate Now (View Announcement)
ASK Me !
- Thread starter .DR.me.
- Start date
How did u do ?
- Messages
- 60
- Reaction score
- 6
- Points
- 8
It was a damn hard paper man
Yeah it was ... How many marks u think u may lose ?It was a damn hard paper man
- Messages
- 60
- Reaction score
- 6
- Points
- 8
at least 10 :O
- Messages
- 3
- Reaction score
- 0
- Points
- 1
biology paper 1B june 2013 anyone take this exam ??
- Messages
- 178
- Reaction score
- 30
- Points
- 38
hey everyone , please can someone explain why the answer to this multiple choice questions is B ? How can I decide whether it gives racemic mixture or not?
http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/January%202012%20-%20QP/6CH04_01_que_20120307.pdf
question 10(a)
http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/January%202012%20-%20QP/6CH04_01_que_20120307.pdf
question 10(a)
Help! Maybe this seems easy, but I don't seem to follow it properlyyy.
Okay so for thermodynamics, apparently in Exothermic reactions, when bonds are formed, more energy is released than the amount of energy absorbed in breaking the bonds. However, the value of change in energy for exothermic reactions is negative, but if the change in energy is calculated by "Energy released in products - Energy absorbed in reactants", how can it be negative is the energy released in products is greater than the energy absorbed in reactants? Shouldn't it be positive?
Yes it must b positive if so .. U understand the whole process way too good I must say
But the formula that gives the delta H ( enthalpy change of the reaction) is = to the potential energy of product - the potential energy of the reactant
And since products have less energy and reactant more so the total value will b -ve
Ok so racemic mixture is a mixture that contains equal amount of both enantiomers ( isomers that rotate a polarised light clockwise and anti )
For this enantiomers to b produced , there should b a choral carbon ...
And a choral carbon is one that has different groups joined to it
Here u should b looking at the c double bond o , all have 3 different groups bonded to that c except the one in b
Since it has an oxygen and 2 similar (ch2ch3)
No 3 different groups , so it won't form the optically active isomers
- Messages
- 178
- Reaction score
- 30
- Points
- 38
but a chiral carbon should have 4 diferent groups , the one with c double bond o has only three different groups there is no 4th one
Okay great, thanks! Could you also explain pie and sigma bonds to me plesae?
Loo
So the c double bond o will be havin cn bonded with an h as I remember ...
Making it have 4 dif bonds
But anyhow since all have that c double bond o , don't waste ur time on that common thing but try and figure the difference
Between all
Ya that's true , the question asks after the rxn with cn which will have a racemic mixture
So the c double bond o will be havin cn bonded with an h as I remember ...
Making it have 4 dif bonds
But anyhow since all have that c double bond o , don't waste ur time on that common thing but try and figure the difference
Between all
Pi and sigma ?
Sigma is a stronger bond than pi
Pi is a result of an overlap of p orbitals
Sigma-pi bond is the double bond
I dono how we need this exactly
Know how to draw them in case , but I don't think this is to come
- Messages
- 178
- Reaction score
- 30
- Points
- 38
Okay understood that! thanks alot
What do you mean by "an overlap in p orbitals" ?
And in June 2012, Unit 1 Question 12, why is C2H6 the product which provides the strongest evidence for a free radical mechanism?
How are you so good at chemistry? Do you study lots for it?
U
The p orbitals parallel to each other overlap makin a pi bond
I don't really know that , maybe only uv light is needed with no energy to form the radical
Due to the saturation of the Alkane
U can b so good ... Just concentrate while studying and solve much
If anyone can ,u can
U got s , p ,d,f orbitals ...
The p orbitals parallel to each other overlap makin a pi bond
I don't really know that , maybe only uv light is needed with no energy to form the radical
Due to the saturation of the Alkane
U can b so good ... Just concentrate while studying and solve much
If anyone can ,u can
- Messages
- 34
- Reaction score
- 4
- Points
- 8
Hi!
I just posted this thread: https://www.xtremepapers.com/community/threads/igcse-a-as-level-math-physics.26974/I hope you can answer my question.. Would I be able to answer the International GCSE Math exam if I only study AS & A level Math?
Would I b able to answer igcse maths ?Hi!
I hope you can answer my question.. Would I be able to answer the International GCSE Math exam if I only study AS & A level Math?
I dono
- Messages
- 34
- Reaction score
- 4
- Points
- 8
- Messages
- 178
- Reaction score
- 30
- Points
- 38
discuss the uncertainty of measurements and their implications
for the validity of the final results
please answer this for me
for the validity of the final results
please answer this for me