Answer
$[I_2] = 0.194 \space M$
$[I] = 8.58 \times 10^{-4} M$
Work Step by Step
- Calculate all the concentrations:
$$[I_2] = ( 0.0456 )/(2.30) = 0.0198 M$$
1. Write the equilibrium constant expression:
- The exponent of each concentration is equal to its balance coefficient.
$$K_c = \frac{[Products]}{[Reactants]} = \frac{[ I ]^{ 2 }}{[ I_2 ]}$$
2. At equilibrium, these are the concentrations of each compound:
$[ I_2 ] = 0.0198 \space M - x$
$[ I ] = 0 \space M + 2x$
$$3.80 \times 10^{-5} = \frac{(2x)^2}{(0.0198 - x)}$$
x = $4.29 \times 10^{-4}$
$[I_2] = 0.0198 - 4.29 \times 10^{-4} = 0.194 \space M$
$[I] = 2(4.29 \times 10^{-4}) = 8.58 \times 10^{-4} M$
