H2O (l) + CO2(g) H2CO3(aq) expression for the following reaction in terms of KC and KP.
H2O (l) + CO2(g) ===> H2CO3(aq)
Kc = (H2CO3)/(H2O)(CO2) = ?
for Kp, substitute pressure for concentration in the above.
To write the expression for the given reaction, we need to determine the stoichiometric coefficients of the balanced equation and then use them to derive the equilibrium constant expressions KC and KP.
The given reaction is:
H2O (l) + CO2(g) ⇌ H2CO3(aq)
Step 1: Write the balanced equation
Assuming that the reaction occurs at standard conditions, we can write the balanced equation as:
H2O (l) + CO2(g) ⇌ H2CO3(aq)
Step 2: Write the equilibrium constant expression KC
KC is the equilibrium constant expressed in terms of the concentrations of the species involved. The equilibrium constant expression KC can be written as:
KC = [H2CO3(aq)] / ([H2O (l)] * [CO2(g)])
Step 3: Write the equilibrium constant expression KP
KP is the equilibrium constant expressed in terms of the partial pressures of the gaseous species involved. However, in this case, only CO2 is a gas. Therefore, we can write the equilibrium constant expression KP as:
KP = P(H2CO3(aq)) / (P(H2O (l)) * P(CO2(g)))
Note: Since H2O (liquid) and H2CO3(aq) are in the same phase, their concentrations and partial pressures are denoted as their activities, which are considered to be approximately equal to 1.
So, the expression for the given reaction in terms of KC and KP is:
KC = [H2CO3(aq)]
KP = P(H2CO3(aq)) / P(CO2(g))
Keep in mind that these equilibrium constant expressions assume that the reaction is taking place at standard conditions. If the reaction occurs at non-standard conditions, the equilibrium constant expressions could be modified.