Bromine is a reddish-brown liquid that vaporises at room temperature. Some liquid bromine is put in a closed jar. The colour of the bromine vapour above the liquid gets darker and darker until the depth of colour remains constant. Bromine liquid still remains in the jar. Explain what is happening in terms of changes in concentration of the bromine molecules in the vapour.

Calculate the value of ${\mathrm{K}}_{\mathrm{c}}$ for the following reaction using the information below: ${\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)\rightleftharpoons {\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)+\mathrm{CO}\left(\mathrm{g}\right)$.

Initial concentration of ${\mathrm{H}}_2\left(\mathrm{g}\right)=10.00 \mathrm{mol} {\mathrm{dm}}^{-3}$.

Initial concentration of ${\mathrm{CO}}_2\left(\mathrm{g}\right)=10.00 \mathrm{mol} {\mathrm{dm}}^{-3}$.

Equilibrium concentration of $\mathrm{CO}\left(\mathrm{g}\right)=9.47 \mathrm{mol} {\mathrm{dm}}^{-3}$.

Nitrogen and hydrogen react together to form ammonia.

${\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3\left(\mathrm{g}\right)$.

$0.1 \mathrm{mol}$ of nitrogen and $0.1 \mathrm{mol}$ of hydrogen were mixed in a closed container of volume $1 {\mathrm{dm}}^3$. At equilibrium $\mathrm{n} \mathrm{mol}$ ammonia is formed. What is the concentration of hydrogen at equilibrium?