Question

what is enthalpy?

Answer 1

Enthalphy is the total heat content of the system i.e addition of internal energy of system and multiplication of pressure and volume the system. Enthalphy is denoted by the symbol H and it is mathematiclly represented as

H = E + P

where,

E is internal Energy of the system

P and V are Pressure and Volume respectively

Enthalphy is a state function

Enthalphy of system can not determined by experimentally but the enthalphy change of the system can be determined by experimentally

if initial enthalphy of the system is represented by H1 and final enthalphy of system is represented by H2

H1 = E1 + P1V1

H2 = E2 + P2V2

H2 - H1 = (E2 - E1) - (P2V2 - P1V1)

DeltaH = DeltaE - PDeltaV

where,

PDeltaV=work done by the system

So, Enthalphy change of the system is equal to internal Energy of the system minus work done by the system