Question

Write an equilibrium expression for each chemical equation which contains one or more solid or liquid reactants or products.

a. CO3^(2-)(aq)+H2O(l)=>HCO3^(-)(aq)+OH^(-)(aq)

b. 2KClO3(s)=>2KCl(s)+3O2(g)

c. HF(aq)+H2O(l)=>H3O^(+)(aq)+F^(-)(aq)

d. NH3(aq)+H2O(l)=>NH4(+)(aq)+OH^(-)(aq)

Answer 1

a) K=
`([HCO_(3)^(-)]_((aq)) [OH^(-) ]_((aq)) )/([CO_(3)^(2-)]_((aq)) )`

b) Kc=[O₂](aq) and Kp= P(O₂)³

c) K=
`( [H_(3)O^(-)]_((aq)) [F^(-)]_((aq)) )/( [HF]_((aq)) )`

d) K=
`( [NH_(4)^(+) ]_((aq)) [OH^(-) ]_((aq)) )/( [NH_(3)]_((aq)))`

Step-by-step explanation:

In a general reaction aA+ bB ⇒ cC

The equilibrium expression is given as follows:

K =
`( [C ]^(c) )/( [ A]^(a) [ B]^(b) )`

Where C is the product and A and B are the reactants, in the expression are included their concentrations. Notice that in the expression both products and reactants are rised by their coefficients.

Furthermore, in the expression appear only aqueous species. Pure solids and liquids (denoted by (l) and (s)) are not included in the expression.

In the reactions:

a) H₂O is not included because it is a pure liquid.

b) Both KClO₃ and KCl are solids and are not included in the expression. O₂ is in gaseous phase, so the equilibrium expression is given by its partial pressure (Kp) or can be given by its aqueos concentration if it is dissolved (Kc).

c) and d) H₂O is not included because it is a pure liquid.