What would happen if I increased the concentration of NOBr in the reaction: 2NOBr (g)+48.4 kJ/mol --> 2NO(g)+Br2(g)
If you increase the amount of NOBr, Le Chatelier's principle tells us that the reaction will favor the forward reaction. Therefore, more NO and Br2 will be produced. For every one mole of Br2 that is generated after the addition, we will also get 2 moles of NO Since this is an endothermic reaction heat is required and consumed in the reaction. The addition of NOBr will require more energy for the reaction to proceed.
Remember that Le Chatelier's principle tells us that when a system at equiLibrium is disturbed, the system will respond the minimize the disturbance.