how is enthalpy change occurs at constt. temperature if change in deltaH is heat absorbed or released which causes change in temperature

Question

anonymous · Answer

@ganeshie8 @MrNood

ookawaiioo · Answer

When bonds are formed, they release energy. 

Heat is a form of energy

anonymous · Answer

this form of  energy leads to increase in the temperature
isnt it @oOKawaiiOo

ookawaiioo · Answer

If volume is expandable, then it wont lead to an increased in temperature.

surry99 · Answer

I can help you but can you restate your question please?

anonymous · Answer

in my book it is written that$$\Delta U=q _{p}-p  \Delta v $$ at constt.temperature
but all the heat is not dissipated as work unless $$\Delta U=0$$ and also$$\Delta H=q _{p}$$ so change in enthalpy also occurs at constt. temp.
SO the question is WHY IN THE BOOK IT IS WRITTEN THAT DELTA U OCCURS AT CONSTT. TEMPERATURE ? AS ANY AMOUNT OF HEAT WOULD CHANGE THE TEMPERATURE...
is the temp. not changed due to the latent heat absorbed by the substance present in the system....

anonymous · Answer

@surry99

surry99 · Answer

hi,
It should say constant pressure not constant temperature.
By defintion:
H = U + PV   or U = H -PV
now if pressure is constant  

deltaU = DeltaH - PdeltaV   

 and it can be shown that at constant pressure deltaH = qp

so at constant pressure
deltaU = qp - PdeltaV