Kc=1. The initial concentrations are A = 0M, B = 0M, C=10M.
A+B --> C
calculate the reaction quotient.
(c)/(a)(b) = 10/0 .. is the answer zero?
No, 10/0 is an indeterminate value. You can prove that to yourself.
10/0 = 0 but 0*0 = 0 which isn't 10.
10/0 = 1 but 1*0 = 0 which isn't 10.
10/0 = 5 but 5*0 = 0 which isn't 10.
10/0 = 1,000 but 1000*0 = 0 which isn't 10. etc.
The bottom line to the answer of 10/0 = any number you pick because any number you choose will have that number * 0 and that will be zero and not 10. The math profs may not like my explanation; they probably have an elegant proof that I don't know. But this will give you the idea.
well if it is undefined, which way would the equilibrium shift?
C is too large; a and b are too small so it will shift to the left.
To calculate the reaction quotient (Q), you need to substitute the current concentrations of the reactants and products into the expression for Q. In this case, the reaction is given as:
A + B → C
The reaction quotient is defined as the ratio of the product concentrations to the reactant concentrations, where each concentration is raised to the power of its stoichiometric coefficient in the balanced equation.
Given the initial concentrations: A = 0 M, B = 0 M, and C = 10 M, we can substitute these values into the formula for Q.
Q = [C]^c /[A]^a [B]^b
And since the stoichiometric coefficients for A, B, and C are 1:
Q = [C]^1 /[A]^1 [B]^1
Substituting the concentrations:
Q = (10 M)^1 / (0 M)^1 (0 M)^1
However, observe that dividing by zero is undefined, so you cannot evaluate Q directly when there is a zero concentration in the denominator. In this case, the reaction has not yet started, and the concentration of A and B is zero, resulting in an undefined reaction quotient.
Hence, the answer is not zero, but rather undefined.