Question

The system below was at equilibrium. The

container is placed on a heating plate and
warmed. What change will occur for the
system?
2NO(g) + O2(g) 2NO2(g) + 113.06 kJ

The reaction will shift toward the reactants left and decrease the concentration of NO2
The reaction will shift toward the reactants left and decrease the concentrations of NO and O2
The reaction will shift toward the products right and increase the concentration of NO2
The reaction will not change because it was already there

Answer 1

The reaction will shift toward the reactants left and decrease the concentrations of NO2.

Step-by-step explanation:

The reaction 2NO(g) + O2(g) → 2NO2(g) + 113.06 kJ involves the formation of NO2 from NO and O2, and it is exothermic, releasing 113.06 kJ of heat.

According to Le Chatelier's principle, when a system at equilibrium is subjected to a stress, it will respond by shifting in a way that minimizes the effect of the stress. The stress in this case is the increase in temperature due to the heating plate.

Since the reaction is exothermic, increasing the temperature will favor the reaction that absorbs heat, which is the reactants side. Therefore, the equilibrium will shift to the left, towards the reactants, to consume some of the excess heat. This means that the concentrations of NO and O2 will increase, while the concentration of NO2 will decrease.

Therefore, the correct answer is: The reaction will shift toward the reactants left and decrease the concentrations of NO2.