Thermochemistry Homework Help?

[AZeyC]

Can anyone help me on a couple of these thermochemistry homework questions:

1 Why is the symbol DH chosen for the heat of a reaction?

2 Compare exothermic and endothermic reactions in terms of:

(i) heat change with the surroundings;
(ii) the sign of DH;
(iii) energy levels of reactants and products.

3 Energy is lost in an exothermic reaction. Does this break the law of conservation of energy? Explain.

4 Draw fully-labelled energy level diagrams for the reactions represented by the following equations:

(i) CH4 (g) + 202 (g) = C02 (g) + 2H2O (l)
DH = —894 kJ
(ii) KNO3 (s) = K+ (aq) + N03-(aq)
DH = +34.6 kJ

[delight1]

wikipedia ftw

[PopeOfDope]

wikipedia ftw

...Google FTW would have made more sense, that page offers very little relavent information.

Can anyone help me on a couple of these thermochemistry homework questions:

1 Why is the symbol DH chosen for the heat of a reaction?

2 Compare exothermic and endothermic reactions in terms of:

(i) heat change with the surroundings;
(ii) the sign of DH;
(iii) energy levels of reactants and products.

3 Energy is lost in an exothermic reaction. Does this break the law of conservation of energy? Explain.

4 Draw fully-labelled energy level diagrams for the reactions represented by the following equations:

(i) CH4 (g) + 202 (g) = C02 (g) + 2H2O (l)
DH = —894 kJ
(ii) KNO3 (s) = K+ (aq) + N03-(aq)
DH = +34.6 kJ

I am not doing your homework for you. GCSE chemistry was easy :) http://www.gcsescience.com/rc23.htm

[bossmanuk]

Why yes it was, I got AA in GCSE Science double award with no revision . I think it has got a bit harder since I was in school though, the stuff my sister has to do seems more difficult than what I had to do.

[AZeyC]

Believe it or not I'm 14 and this is year 9 work, any help would be appreciated. I have used wikipedia and can answer question 2!

[eldiablov]

Believe it or not I'm 14 and this is year 9 work, any help would be appreciated. I have used wikipedia and can answer question 2!

what exam board are you with ?

[leejames04]

i'm gonna say we didn't do that in year 9 crikey that is hard for year 9

[Sir_Axxewraith]

It is for me aswell, I'm in year 9 and in a program where they throw you into GCSE early