In the reaction, PCl3 + Cl2 ------> PCl5 the concentration of the reactants at equilibrium were each determined to be 7.2 mol/L, and the product at 0.050 mol/L.
Calculate the equilibrium constant (rounding to 2 significant figures and using scientific notation), and state in which direction the equilibrium lies.
I don't understand your problem. This is just a case of substituting the numbers into the Keq expression and calculating K.
To calculate the equilibrium constant (K) for this reaction, we need to use the concentrations of the reactants and products at equilibrium.
The balanced equation for the reaction is:
PCl3 + Cl2 → PCl5
Given concentrations:
[PCl3] = [Cl2] = 7.2 mol/L
[PCl5] = 0.050 mol/L
The equilibrium constant expression (Kc) for this reaction is:
Kc = [PCl5] / ([PCl3] * [Cl2])
Plugging in the given values:
Kc = 0.050 mol/L / (7.2 mol/L * 7.2 mol/L)
Simplifying the expression:
Kc = 0.050 / (7.2 * 7.2) = 0.000914 (rounded to 2 significant figures)
Therefore, the equilibrium constant (Kc) for this reaction is 9.1 x 10^-4.
To determine in which direction the equilibrium lies, we look at the magnitude of the equilibrium constant. If Kc is greater than 1, the reaction favors the products. If Kc is less than 1, the reaction favors the reactants. If Kc is approximately equal to 1, then the reaction is at equilibrium.
In this case, since Kc is very small (0.000914), the equilibrium lies towards the reactants. This means that the reaction is primarily proceeding towards the left side, and only a small amount of product is formed.