Hydrogen iodide decomposes according to the equation

CHEMISTRY · Multi-part · AP · Chemistry · Equilibrium · Equilibrium

Problem

2\text{HI}(g) \rightleftharpoons \text{H}_{2}(g)+\text{I}_{2}(g)

. A sealed

2.00\,\text{L}

vessel at

700\,\text{K}

contains the following amounts: •

0.800\,\text{mol}

HI (g) •

0.0500\,\text{mol}

_2

(g) •

0.0500\,\text{mol}

_2

(g) The total pressure in the vessel is measured to be

3.25\,\text{atm}

. For the same reaction at

700\,\text{K}

K_c=1.70\times10^{-2}

. (a) Calculate the reaction quotient

Q_c

for the mixture as written. (b) Using the total pressure, determine the partial pressure of each species and calculate the reaction quotient

Q_p

. (c) By comparing the values of

Q_c

and

K_c

, predict the direction in which the system will proceed to reach equilibrium. Justify your reasoning with numerical evidence.