This discussion is now closed.

Check out other Related discussions

OCR Chemistry F322~ 4th June 2013~ AS Chemistry

Scroll to see replies

Reply 140

TheFootyKing19

Original post by otrivine

Hi up for revision on ehtnalpy and organic

Define average bond enthlapy? (2)
Why is bond enthalpy always positive? (1)
Define Standard enthlapy change of reaction and state the standard (3)
How does a catalyst increase the rate of reaction? (3)
Define Hess's Law? (1)

Reply 141

otrivine

Original post by TheFootyKing19

1) average bond enthalpy is the mean enthalpy change when 1 mole of homolytic fission is broken in a covalent substance to form 1 mole of gaseous ions under standard conditions.

2) because energy is absorbed more than released and breaking bonds is endothermic as energy is taken in , in order to break the bonds.

3) standard enthalpy change of reaction is the enthalpy change when a chemical reaction is expressed in molar quantities, also, reactant and product must be in the same standard state/condition which are 298 K(25 degresS) , 100KPa (1 atm pressure) and concentration of 1 mol dm-3.

4) catalyst increases a rate of reaction by providing an alternative pathway in lowering the activation energy. Ensure that molecules attain more kinetic energy before it reaches its activation energy and so reaction takes place faster and is normall distibuted in a boltzman distribution.

5)Hess law states that if a reaction can take place in more than 1 route and that the initial and final conditions are the same, the total enthalpy change for any route taken would be the same.

Reply 142

Jimmy20002012

Anyone know how to tackle Infrared spectroscopy and mass spec long answer questions?

Posted from TSR Mobile

Reply 143

That_Clever_Guy

Original post by Jimmy20002012

Anyone know how to tackle Infrared spectroscopy and mass spec long answer questions?

Posted from TSR Mobile

I like to annotate my graphs :smile:

this then helps structure your answer and get full marks :smile:

hope that helped

Posted from TSR Mobile

Reply 144

Shiva...

Does anyone know what kind of questions will be asked for the enthalpy change of combustion evaluative task?

Reply 145

purplemind

Original post by Shiva...

Does anyone know what kind of questions will be asked for the enthalpy change of combustion evaluative task?

I think it isn't allowed to say, am I right? :biggrin:

Reply 146

Freddy-Francis

Original post by TheFootyKing19

I got BB both times. High B's though.

Full ums here i come...

I got mine. I got 13/15, 6/10 and 13/15 and so overall 32/40. B too :smile:

Reply 147

furryface12

Original post by Freddy-Francis

I got mine. I got 13/15, 6/10 and 13/15 and so overall 32/40. B too :smile:

Mine currently stands at 9/10, 12/15, 7/15, so a C I think. Guess which one I'm retaking...

Posted from TSR Mobile

Reply 148

Gotzz

Mine is currently 14/15 and 8/10 I think, and I still have the evaluative to do.

Reply 149

purplemind

I have 14/15 (quantitative), 15/15 (evaluative) and 10/10 (qualitative). :tongue:

Reply 150

CurtisDean

Well done on ISA results people!
I have my Qual F323 tomorrow! About reactions of Group 2 compounds!
Wish me luck! :smile:

This was posted from The Student Room's iPhone/iPad App

Reply 151

otrivine

Original post by purplemind

I have 14/15 (quantitative), 15/15 (evaluative) and 10/10 (qualitative). :tongue:

Hi want to revise enthalpy and organic

Reply 152

SchoolKid.

Original post by CurtisDean

Well done on ISA results people!
I have my Qual F323 tomorrow! About reactions of Group 2 compounds!
Wish me luck! :smile:

This was posted from The Student Room's iPhone/iPad App

Make sure you read all the questions properly and dont do what I did :frown:

Good luck

Reply 153

Gotzz

Original post by purplemind

I have 14/15 (quantitative), 15/15 (evaluative) and 10/10 (qualitative). :tongue:

Well done, that's awesome :smile:

Reply 154

otrivine

Original post by Gotzz

Well done, that's awesome :smile:

Hi want to revise on enthalpy and organic

Reply 155

purplemind

Original post by Gotzz

Well done, that's awesome :smile:

Thank you. :smile:

I think that would be enough but my teacher told me to have a second go at quantitative to see if I can get I more mark, but I won't be stressed about this anymore. :colondollar:

Reply 156

Gotzz

Original post by purplemind

Thank you. :smile:

I think that would be enough but my teacher told me to have a second go at quantitative to see if I can get I more mark, but I won't be stressed about this anymore. :colondollar:

Haha it must be so nice to not have to stress about it anymore :smile:

I also have 14/15 in the quantitative but will probably have another go because I think the rest of my class will :P

Reply 157

purplemind

Original post by Gotzz

Haha it must be so nice to not have to stress about it anymore :smile:

I also have 14/15 in the quantitative but will probably have another go because I think the rest of my class will :P

Was titration your first one? (I hate titrations. :biggrin:

)

Reply 158

Gotzz

Original post by purplemind

Was titration your first one? (I hate titrations. :biggrin:

)

Haha yeah, I did titrations quite a long time ago and got 13/15 (lost both of the marks on the last question). And then I did the one on enthalpy changes :smile:

Reply 159

purplemind

Original post by Gotzz

Haha yeah, I did titrations quite a long time ago and got 13/15 (lost both of the marks on the last question). And then I did the one on enthalpy changes :smile: