GIVEN THE SYSTEM,
SO2 + O2 = 2SO3
WRITE DOWN THE EXPRESSION FOR Kc AND STATE IT UNIT
To write down the expression for the equilibrium constant (Kc) for a given reaction, you need to understand two key concepts:
1. The equilibrium constant represents the ratio of the concentrations of the products to the concentrations of the reactants, with each concentration term raised to the power of its respective stoichiometric coefficient.
2. The expression for Kc only includes the species involved in the balanced chemical equation, excluding any pure solids or liquids.
In the given system, the balanced equation is:
SO2 + O2 -> 2SO3
The expression for Kc is as follows:
Kc = [SO3]^2 / [SO2] * [O2]
Here's how you can calculate the concentrations of each species at equilibrium:
1. Calculate the concentration of SO2 by dividing the moles of SO2 by the volume of the container in liters.
Concentration of SO2 = n(SO2) / V
2. Calculate the concentration of O2 using the same approach as for SO2.
Concentration of O2 = n(O2) / V
3. Calculate the concentration of SO3 by dividing the moles of SO3 by the volume of the container in liters.
Concentration of SO3 = n(SO3) / V
4. Substitute these concentration values into the Kc expression and solve for Kc.
The unit for Kc will depend on the units used for the concentrations of the species. For example, if the concentrations are expressed in moles per liter, Kc will have the unit of (mol/L)^2.