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AQA Chemistry Paper 2 AS Level 2016 Unofficial Mark Scheme

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Original post by Splaffie
this is exactly what i wrote and im 99% sure it was what they were looking for


In June 2015 it says:
"heat loss or not all heat transferred to the apparatus or heat absorbed by the apparatus or (specific) heat capacity of the apparatus not considered
• incomplete combustion / not completely burned / reaction is not complete
• The idea that the water may end up in the gaseous state (rather than liquid) • reactants and/or products may not be in standard states. (Ignore this one as it was not asking for standard enthalpy) "
Original post by DaVinciGirl
In June 2015 it says:
"heat loss or not all heat transferred to the apparatus or heat absorbed by the apparatus or (specific) heat capacity of the apparatus not considered
• incomplete combustion / not completely burned / reaction is not complete
• The idea that the water may end up in the gaseous state (rather than liquid) • reactants and/or products may not be in standard states. (Ignore this one as it was not asking for standard enthalpy) "


this year i noticed a focused on average bond enthalpy with these types of questions, ESPECIALLY data book values, it also said to ignore heat loss or incomplete combustion
Original post by DaVinciGirl
In June 2015 it says:
"heat loss or not all heat transferred to the apparatus or heat absorbed by the apparatus or (specific) heat capacity of the apparatus not considered
• incomplete combustion / not completely burned / reaction is not complete
• The idea that the water may end up in the gaseous state (rather than liquid) • reactants and/or products may not be in standard states. (Ignore this one as it was not asking for standard enthalpy) "


My teacher mentioned an alternative point that multiple different experiments would have been conducted to obtain an average for data book values but this was one individual experiment?
Original post by Splaffie
it specifically said to not write about heat loss


No, im 100% sure mine said without incomplete combustion or heat transferred to the atmosphere
My book makes 4 points:
1.) heat absorbed by container
2.) heat transferred to the surroundings
3.) incomplete combustion
4.) flammable liquid escaping by evaporation
So there are two options to choose from
(This is from the CGP complete course)
(edited 7 years ago)
Original post by Splaffie
this year i noticed a focused on average bond enthalpy with these types of questions, ESPECIALLY data book values, it also said to ignore heat loss or incomplete combustion

I see what you mean. It's definitely a point. I do think for these question there maybe two or more answers to it. For me I was ensure with the fact if data book uses mean bond enthalpy and that's the reason why. Also it did say ignore heat loss to the atomosphere for sure.
Original post by DaVinciGirl
It specifically said not to write about heat loss to the ATMOSPHERE. :smile:


Exactly ATMOSPHERE not calorimeter
Yes you two are agreeing haha ^
I just rote "1.31%"
Will I get the mark
Original post by gcsekid
Exactly ATMOSPHERE not calorimeter

I thought it said enviroment, not atmosphere.....so it's pretty ambiguous either way.
Original post by gcsekid
Exactly ATMOSPHERE not calorimeter


when they say heat loss to the atmosphere, they mean heat loss to literally everything else
Original post by marcobruni98
Yes you two are agreeing haha ^


Haha lol feels good when theres 2 of u agreein
Original post by Splaffie
when they say heat loss to the atmosphere, they mean heat loss to literally everything else


What was your answer btw??
Original post by Splaffie
when they say heat loss to the atmosphere, they mean heat loss to literally everything else


Well i dont call a calorimeter an atmosphere so they best well give me a mark
Original post by Splaffie
when they say heat loss to the atmosphere, they mean heat loss to literally everything else

You cannot be serious. I have already shown the answers from the book!
Original post by gcsekid
Well i dont call a calorimeter an atmosphere so they best well give me a mark


But the calorimeter is part of the atmosphere. Atmosphere doesn't mean air - it means everything external to what you're concerned about (in this case, the ethanol)
Original post by rosemondtan
But the calorimeter is part of the atmosphere. Atmosphere doesn't mean air - it means everything external to what you're concerned about (in this case, the ethanol)

google atmosphere m8
(edited 7 years ago)
Original post by marcobruni98
google atmosphere m8


you dont understand, heat loss to the atmosphere means heat loss from the spirit burner
Original post by Splaffie
you dont understand, heat loss to the atmosphere means heat loss from the spirit burner


Yup!! Couldn't think of one so I just went for a generic answer - data booklet would have included different experiments to obtain an average value while this is one isolated experiment lmao
Original post by rosemondtan
Yup!! Couldn't think of one so I just went for a generic answer - data booklet would have included different experiments to obtain an average value while this is one isolated experiment lmao


especially since iirc in the specimen papers there was a question like this where the answer was mean bond enthalpy

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