OCR A 3.2.1 Enthalpy changes REVISION

[enchantmentoverride]

Thank you so much for the video! You made Hess cycle seem less scary and actually much easier to understand than from the textbook😁

[newplatypus]

This is the one topic I never understood but this is so well explained and simple, I now finally get it. Thank you so much!

[livyaxx]

Hello, I was hoping if you could make a video on hardest calculation questions in chemistry. Thanks!

[aaryanramani]

My favourite videos for ENTHALPY.... Thanks so much for explaining the definitions and conditions so clearly!!!

[simranxpanesar]

This was really well explained however I'm slightly confused about how you work out what goes at the bottom of the cycle and the number of moles it has, could you explain it for me please?

[arjunaich]

Is it just me or are the cycles the wrong way round for the questions. For calculating the enthalpy of formation, he drew a combustion cycle and vice versa for enthalpy of combustion.

[zaynaba]

Thank you! your videos are live savers!

[Tibialisanterior]

at 22:36 did you mean this the 'enthalpy of formation'?? isnt it meant to be combustion due to our arrows facing down?

[aks]

how did you balance the numbers at the bottom of the enthalpy cycle I don't get that bit

[julkamikula]

amazing thanks so much saving my mocks !!!

[joeknox]

Hi Chris,
in combustion cycles do you never count the enthalpy of combustion of oxygen?

[p.p]

For calorimetry the question gives the temperature change in degrees Celsius, so do we not convert to this to kelvin? In the markscheme it's not converted to kelvin. Thank you

[trihardFTW]

Hi there,
what do you mean by "start anywhere on the cycle and add up the numbers" - i don't understand what numbers you're talking about? if you can clarify this. thanks!

[acegamer]

19:05 Why is there only 1 carbon in elements for formation isnt there supposed to be 2 Carbons as there is one in methanol and one in carbon dioxide?

[ellasidney]

at 18:05, why did you use 1.5O2 rather than 3O2?

[shyamkanjee]

So basically bond dissociation enthalpy is the energy required per mole to break the intermolecular forces of attractions between the gaseous compounds, like Cl2?

[shyamkanjee]

Hey Chris, are these videos for the old spec or the new one?

[abi.anderson]

Hi, what if you are given the values for enthalpy of reaction and need to find the enthalpy of combustion or formation? Which way do the arrows go?

[reubenconstantine]

Sir I have a massive issue I need help trying to understand... if products have higher energy than reactants surely that means it’s exothermic as more energy is released when the product is formed than the energy required to break the reactants’ bonds? Yet the diagram is labelled endothermic?

[joeatty]

For the calorimetry equation does temperature have to be in K?