AQA CHEM2 ~ May 23rd 2012 ~ AS Chemistry
Chemistry exam discussion - share revision tips in preparation for GCSE, A Level and other chemistry exams and discuss how they went afterwards.
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Re: AQA CHEM2 ~ May 23rd 2012 ~ AS ChemistryAll definitions you need are for Energetics pretty much are:(Original post by cuckoo99)
hate energetics, so many definitions to remember and that hess's law **** is effort
- Enthalpy Change
- Enthalpy of Formation
- Enthalpy of Combustion
- Hess's Law
- State the Standard Conditions
- Mean Bond Enthalpy
And know Exothermic is energy given out, Endothermic is energy taken in.
Know that Q=mc/\T (mc delta t), /\H=Q/moles. -
Re: AQA CHEM2 ~ May 23rd 2012 ~ AS Chemistry
TOPIC 2.1 - ENERGETICS
Exothermic - Give out heat (NEGATIVE) - /\H is NEGATIVE
Endothermic - Take in heat (POSITIVE) - /\H is POSITIVE
/\H - Enthalpy Change - The Enthalpy change for a reaction is the heat energy change measured under conditions of constant pressure.
The Standard Enthalpy Change for a reaction is the heat energy change measured under standard conditions: 100kPa and 298K (and all reactants+products in their standard states).
Enthalpy changes are measured in kJmol -1
So /\H= heat energy change/no. moles (/\H= Q/mol)
STANDARD ENTHALPY OF FORMATION - The Enthalpy change, under standard conditions, when 1 mole of compound is formed from it's elements with all reactants and products in their standard states.
STANDARD ENTHALPY OF COMBUSTION - The Enthalpy change, under standard conditions, when 1 mole of substance is burnt in excess Oxygen, with all reactants and products in their standard states.
----- THE STANDARD ENTHALPY OF FORMATION OF ALL ELEMENTS IN THEIR STANDARD STATES IS 0 -----Last edited by Sorro10; 28-02-2012 at 16:05. -
Re: AQA CHEM2 ~ May 23rd 2012 ~ AS Chemistry
I have my written ISA paper on tuesday, and as far as I can gather from past papers and what the teachers have said, the task is 'to identify the metal ion in a salt, used as a de-icer by a series of observation exercises'
The main areas of the AQA specification (which is online) that you need to look up are 3.1.2 (amount of substance), 3.2.1 (energetics), 3.2.5 (group 7 (17) the halogens), 3.2.6 (group 2, the alkaline earth metals). Not all of this will come up obviously, however I'm still going to revise it all as much as possible in case.
And if you're working out of the AQA textbook chapter 7, 11 and 12 are the ones to look over apparently
good luck to everyone, hope it all goes well -
Re: AQA CHEM2 ~ May 23rd 2012 ~ AS ChemistryOhhh is this the second ISA, have you done your first ISA?(Original post by mybubbles)
I have my written ISA paper on tuesday, and as far as I can gather from past papers and what the teachers have said, the task is 'to identify the metal ion in a salt, used as a de-icer by a series of observation exercises'
The main areas of the AQA specification (which is online) that you need to look up are 3.1.2 (amount of substance), 3.2.1 (energetics), 3.2.5 (group 7 (17) the halogens), 3.2.6 (group 2, the alkaline earth metals). Not all of this will come up obviously, however I'm still going to revise it all as much as possible in case.
And if you're working out of the AQA textbook chapter 7, 11 and 12 are the ones to look over apparently
good luck to everyone, hope it all goes well
Good to hear(Original post by Sorro10)
Almost finished CHEM2 like 2 topics left lol.
Keep up the hard work! Ace CHEM2 and all your Chemistry worries can be laid to rest, CHEM2 is worth the MOST UMS. Worth 20 more UMS in total than any A2 mod!
Get to working!!
PS if anyone needs help etc, let me know! i have a TON of helpful stuff


Get to working!!