Question

Hi, how do I know which is product and which is reactant, when there are just plus signs? Or just arrows?

Like 2NO2(g)⇌N2O4(g) or when it's like this...CO2 (aq) + H2O (l)⇌H (aq) + HCO3. THANK YOU VERY MUCH:):):)

Answer 1

By convention we focus on the forward reaction when we write the equilibrium constant. That is, the products are by convention on the right.

`2"NO"_2(g) rightleftharpoons "N"_2"O"_4(g)`

`K_c = (["products"])/(["reactants"]) = (["N"_2"O"_4])/(["NO"_2]^2)`

`"CO"_2(aq) + "H"_2"O"(l) rightleftharpoons "H"^(+)(aq) + "HCO"_3^(-)(aq)`

`K_c = (["products"])/(["reactants"]) = (["H"^(+)]["HCO"_3^(-)])/(["CO"_2])`