Calculating Enthalpy Changes from Bond Enthalpies

[@theosims-woodhouse2446]

That must be one tough pen lid

[@SolaScriptura49]

Best video on this topic out there! Thanks so much for making this! :)

[@aroosa3835]

I literally got so scared at 6:18

[@sinisterstories540]

Owwwww

[@silencer315]

Great help thanks!

[@MaChemGuy]

Glad it helped!

[@bryanhong4898]

helps a lot ,thank you

[@maxsearle5044]

So is it ALWAYS going to be reactants minus products?

[@MaChemGuy]

From bond enthalpies yes

[@progamingtv1437]

I thought that elements in there normal state have a bond enthalpy of 0. Why is O2 not just 0?

[@MaChemGuy]

ProGamingTV You're thinking of enthalpies if formation for elements which are all zero. The atoms in O2 are strongly attracted to each other (covalent bond) so need an energy input to break

[@beastdestroyer2453]

Can you explain more from questions where you have to change the state of the species

[@oswin4715]

Thanks alot!

[@TP-mv6en]

What does enthalpy actually mean though?

[@sam17simba]

Is it always E in = E out?

[@MaChemGuy]

Nush Ra Enthalpy change = E in - E out

[@OhHaiBrah]

MaChemGuy I don't understand. Why is it that Delta H is normally Sum of Products - Sum of Reagents but in this case it is Reagents - Products?

[@ismarikapandey3370]

why is it reactants - products (in - out) when usually for enthalpy change its products - reactants?

[@MaChemGuy]

Ismarika Pandey When using bond enthalpies it's the energy required to break bonds (E in) - the energy released when bonds are formed (E out) Products - Reactants is the method when using enthalpies of formation. In - out is just my way to explain it.