enthalpy change of combustion alchols

hey! so I am doing PAG 3.3 determination of the enthalpy changes of combustion (OCR A) and stuck on the questions:

2) Evaluate your results by comparing your experimental value to the accepted enthalpy change for the combustion of the alcohol and suggest the reasons why there is a difference

reason I am stuck:
- WHERE ARE THESE ACCEPTED ENTHALPY VALUES?!? I’m trying to look online but everywhere gives different values so idk which one to use. if anyone can help and give the values for: methanol, ethanol, propan-1-ol, but an-1-ol and pentan-1-ol that would be appreciated

4) calculate the enthalpy change of combustion for methanol, ethanol, propanol, butanol and pentanol using bond enthalpies. (you will need to look up values for relevant bonds)

reason I am stuck:
- is this a hess’ law question or am I overthinking this aha?
- where do I find the values for the relevant bonds 😭

thank you so much!

You will find various values. The best thing to do is pick one you like and then in your write-up state where you found the values. You know, a citation , i.e. a reference list. One of the CPAC skills you need to show if referencing. Why not start now?

ok thank you ;”) is number 4 a hess’ law question? oh and about the referencing, I have done that in the research in this pag I don’t need to do it for the extension questions!

You no doubt did bond energy Qs at GCSE, but you didn't call it a Hess' calc then, so why start now (for the record: it is effectively a Hess' calc.)

You don't need to do any extension Qs to be awarded your CPAC skills.

hey! so I am doing PAG 3.3 determination of the enthalpy changes of combustion (OCR A) and stuck on the questions:

2) Evaluate your results by comparing your experimental value to the accepted enthalpy change for the combustion of the alcohol and suggest the reasons why there is a difference

reason I am stuck:
- WHERE ARE THESE ACCEPTED ENTHALPY VALUES?!? I’m trying to look online but everywhere gives different values so idk which one to use. if anyone can help and give the values for: methanol, ethanol, propan-1-ol, but an-1-ol and pentan-1-ol that would be appreciated

4) calculate the enthalpy change of combustion for methanol, ethanol, propanol, butanol and pentanol using bond enthalpies. (you will need to look up values for relevant bonds)

reason I am stuck:
- is this a hess’ law question or am I overthinking this aha?
- where do I find the values for the relevant bonds 😭

thank you so much!