CHEM1102 Thermodynamics Equations

• ΔEsys = q_p + w
• (+ve is endo, -ve is exo)

ΔSuni = ΔS_sys + ΔS_surround

• q = C x ΔT 
• (in JK^-1 or JK^-1g^-1)

• w = -P_exΔV
• ΔE = q

H = E + PV

ΔH = q_p (heat added to system)

ΔH⁰ is standard enthalpy (1 atm, 25⁰C)

Δ_fH⁰ is enthalpy of formation

Δ_reactionH⁰ = ΣnΔ_fH⁰(products) - ΣnΔ_fH⁰(reactants)

Δ_reactionS⁰ = ΣnΔS⁰(products) - ΣnΔS⁰(reactants)

• ΔS_sys = q_rev   JK^-1mol^-1 (q is heat from                         T                     reversible change)

• ΔS_surround = heat transfer in actual process
•                                     T
• = -q_p = -ΔH_sys
•      T       T

• G = H - TS
• ΔG_sys = ΔH_sys - TΔS_sys at constant T

Δ_reactionG⁰ = ΣnΔ_fG⁰(products) - ΣnΔ_fG⁰(reactants)

• ΔG⁰ = - RT lnK
• ΔG = ΔG⁰ + RT lnQ

• G_sys is -ve
• S_uni is +ve

In Equi, both are = 0