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# Chemistry AS level energetics question watch

1. The combustion of methane is an exothermic reaction:
CH4 + 2O2  CO2 + 2H2O ΔH = -890 kJmol-1
Calculate the heat energy released when 100 g of methane is burned
The answer is 5560 kJ but no idea how to get this value
2. How many moles are there in 100g of methane?
3. It's not that hard, one mole of CH4 is 16 grams, so for every 16 grams 890KJ of energy.
So you can just cross multiply and find the energy you get from 100 grams
4. (Original post by imaan2121)
The combustion of methane is an exothermic reaction:
CH4 + 2O2  CO2 + 2H2O ΔH = -890 kJmol-1
Calculate the heat energy released when 100 g of methane is burned
The answer is 5560 kJ but no idea how to get this value
You need to find out the number of moles of CH4 using the n=m/Mr equation
You already know the amount of energy released per mole, -890 kJ mol-1, so then multiply the number of moles found by this value to find out the total amount released
5. wait sorry general ques. comig from a year 11 student...
is chemistry hard at a levels (aqa)
6. (Original post by unillama)
wait sorry general ques. comig from a year 11 student...
is chemistry hard at a levels (aqa)
I would say it's definitely not easy, but not too hard either. I'm doing AS Level at the moment and I find it quite interesting. As a science A level, it's fairly complicated but it depends whether you enjoy the subject.

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