Equilibrium

A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased. a) What is the initial effect of the change on vapour pressure? b) How do rates of evaporation and condensation change initially? c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

What is $K_c$ for the following equilibrium when the equilibrium concentration of each substance is: $[SO_2] = 0.60M, [O_2] = 0.82M$ and $[SO_3] = 1.90M$?

At a certain temperature and total pressure of $10^5$ Pa, iodine vapour contains 40% by volume of I atoms

Calculate $K_p$ for the equilibrium.

Write the expression for the equilibrium constant, $K_c$ for each of the following reactions: (i) $2NOCl(g) \rightleftharpoons 2NO(g) + Cl_2(g)$ (ii) $2Cu(NO_3)_2(s) \rightleftharpoons 2CuO(s) + 4NO_2(g) + O_2(g)$ (iii) $CH_3COOC_2H_5(aq) + H_2O(l) \rightleftharpoons CH_3COOH(aq) + C_2H_5OH(aq)$ (iv) $Fe^{3+}(aq) + 3OH^-(aq) \rightleftharpoons Fe(OH)_3(s)$ (v) $I_2(s) + 5F_2(s) \rightleftharpoons 2IF_5$

Find out the value of $K_c$ for each of the following equilibria from the value of $K_p$: (i) $2NOCl(g) \rightleftharpoons 2NO(g) + Cl_2(g)$; $K_p = 1.8 \times 10^{-2}$ at 500 K (ii) $CaCO_3(s) \rightleftharpoons CaO(s) + CO_2(g)$; $K_p = 167$ at 1073 K

For the following equilibrium, $K_c = 6.3 \times 10^{14}$ at 1000 K

Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is $K_c$, for the reverse reaction?

Explain why pure liquids and solids can be ignored while writing the equilibrium constant expression?

Reaction between $N_2$ and $O_2$ takes place as follows:

If a mixture of 0.482 mol $N_2$ and 0.933 mol of $O_2$ is placed in a 10 L reaction vessel and allowed to form $N_2O$ at a temperature for which $K_c = 2.0 \times 10^{-37}$, determine the composition of equilibrium mixture.

Nitric oxide reacts with $Br_2$ and gives nitrosyl bromide as per reaction given below:

When 0.087 mol of NO and 0.0437 mol of $Br_2$ are mixed in a closed container at constant temperature, 0.0518 mol of NOBr is obtained at equilibrium. Calculate equilibrium amount of NO and $Br_2$.

At 450K, $K_p = 2.0 \times 10^{10}$/bar for the given reaction at equilibrium.

What is $K_c$ at this temperature?

A sample of HI(g) is placed in flask at a pressure of 0.2 atm. At equilibrium the partial pressure of HI(g) is 0.04 atm. What is $K_p$ for the given equilibrium?

A mixture of 1.57 mol of $N_2$, 1.92 mol of $H_2$ and 8.13 mol of $NH_3$ is introduced into a 20 L reaction vessel at 500 K. At this temperature, the equilibrium constant, $K_c$, for the reaction $N_2 (g) + 3H_2 (g) \rightleftharpoons 2NH_3 (g)$ is $1.7 \times 10^2$. Is the reaction mixture at equilibrium? If not, what is the direction of the net reaction?

The equilibrium constant expression for a gas reaction is,

Write the balanced chemical equation corresponding to this expression.

One mole of $H_2O$ and one mole of CO are taken in 10 L vessel and heated to 725 K. At equilibrium 40% of water (by mass) reacts with CO according to the equation,

Calculate the equilibrium constant for the reaction.

At 700 K, equilibrium constant for the reaction:

is 54.8. If 0.5 mol L$^{-1}$ of HI(g) is present at equilibrium at 700 K, what are the concentration of $H_2(g)$ and $I_2(g)$ assuming that we initially started with HI(g) and allowed it to reach equilibrium at 700 K?

What is the equilibrium concentration of each of the substances in the equilibrium when the initial concentration of ICl was 0.78 M?

$K_p = 0.04$ atm at 899 K for the equilibrium shown below. What is the equilibrium concentration of C$_2$H$_6$ when it is placed in a flask at 4.0 atm pressure and allowed to come to equilibrium?

Ethyl acetate is formed by the reaction between ethanol and acetic acid and the equilibrium is represented as:

(i) Write the concentration ratio (reaction quotient), $Q_c$, for this reaction (note: water is not in excess and is not a solvent in this reaction) (ii) At 293 K, if one starts with 1.00 mol of acetic acid and 0.18 mol of ethanol, there is 0.171 mol of ethyl acetate in the final equilibrium mixture. Calculate the equilibrium constant. (iii) Starting with 0.5 mol of ethanol and 1.0 mol of acetic acid and maintaining it at 293 K, 0.214 mol of ethyl acetate is found after sometime. Has equilibrium been reached?

A sample of pure PCl$_5$ was introduced into an evacuated vessel at 473 K. After equilibrium was attained, concentration of PCl$_5$ was found to be $0.5 \times 10^{-1}$ mol L$^{-1}$. If value of $K_c$ is $8.3 \times 10^{-3}$, what are the concentrations of PCl$_3$ and Cl$_2$ at equilibrium?

One of the reaction that takes place in producing steel from iron ore is the reduction of iron(II) oxide by carbon monoxide to give iron metal and CO$_2$.

What are the equilibrium partial pressures of CO and CO$_2$ at 1050 K if the initial partial pressures are: $p_{CO} = 1.4$ atm and $p_{CO_2} = 0.80$ atm?