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Question
Answer in brief.
Obtain the expression for work done in chemical reaction.
Solution
- The work done by a system at constant temperature and pressure is given by
W = - Pext ΔV ....(1) - Assuming Pext = P,
W = - PΔV
= - P (V2 - V1)
W = - PV2 + PV1 .....(2) - If the gases were ideal, at constant temperature and pressure.,
PV1 = n1RT and PV2 = n2RT ....(3)
Substitution of equation (3) into equation (2) yields
W = - n2RT + n1RT
= - (n2 - n1) RT
= - Δng RT .....(4) - The equation (4) gives the work done by the system in chemical reactions.
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