K1_expr a(cFeOH)*a(cH)/(a(cFe)*K1) Equilibrium expression K2_expr a(cH)*a(cOH)/K2 Equilibrium expression K3_expr a(cH)*a(cCH3COO)/(a(cCH3COOH)*K3) Equilibrium expression K4_expr a(cCH3COOFe)/(a(cCH3COO)*a(cFe)*K4) Equilibrium expression r1 -r1_num*log(K1_expr) Rate expression r2 -r2_num*log(K2_expr) Rate expression r3 -r3_num*log(K3_expr) Rate expression r4 -r4_num*log(K4_expr) Rate expression