If the oxygen being fed into the system
4NH3(g) + 5O2(g) <--> 4NO(g) + 6H20(g) + 950kJmol-1
is heated, how will the equilibrium shift?
The reaction is exothermic, that is gives off heat, or raising the temperature. If heat is added, then the reaction will shift to undo what the change was, so it will shift left.
To understand how the equilibrium will shift when the oxygen is heated in the given reaction, it is important to consider Le Chatelier's principle. According to this principle, when a system at equilibrium is subjected to a change in temperature, pressure, or concentration, the equilibrium will shift in a way that tends to counteract the change.
In this case, since the reaction is exothermic (it releases heat as indicated by the negative value of the enthalpy change, -950 kJ/mol), heating the system will increase the temperature. According to Le Chatelier's principle, the system will try to oppose this increase in temperature by shifting in a direction that absorbs heat.
To determine the specific direction of the shift, we should analyze the reaction equation. When the temperature is increased, the reaction will shift in a direction that consumes or absorbs heat. In the given reaction, four molecules of ammonia (NH3) and five molecules of oxygen (O2) form four molecules of nitric oxide (NO), six molecules of water (H2O), and release 950 kJ/mol of heat.
Therefore, to absorb the excess heat, the equilibrium will shift to the left, towards the reactants (NH3 and O2) side of the equation. By shifting left, the system will consume more ammonia and oxygen to form more nitric oxide and water, thereby reducing the temperature.
In summary, when the oxygen is heated in the given reaction, the equilibrium will shift to the left to counteract the increase in temperature, consuming more ammonia and oxygen to form more nitric oxide and water.