To understand how the system will change when it is heated, we need to consider Le Chatelier's Principle, which states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium will move to counteract the change.
In the given reaction:
[tex]\[ 2 \text{NO} ( g ) + \text{O}_2 (g) \rightleftharpoons 2 \text{NO}_2 (g) + \text{heat} \][/tex]
the reaction releases heat, making it an exothermic reaction. According to Le Chatelier's Principle, if we add heat to the system by warming the container, the equilibrium will shift in the direction that counteracts this change, that is, it will shift in the direction that absorbs heat.
For an exothermic reaction, the reverse reaction (toward the reactants) is endothermic, meaning it absorbs heat. Hence, heating the system will result in the equilibrium shifting to the left, towards the reactants.
As a result of this shift:
1. The concentration of the products ([tex]\(\text{NO}_2\)[/tex]) will decrease.
2. The concentration of the reactants ([tex]\(\text{NO}\)[/tex] and [tex]\(\text{O}_2\)[/tex]) will increase.
Therefore, the correct statement is:
The reaction will shift toward the reactants (left) and decrease the concentration of [tex]\( \text{NO}_2 \)[/tex].
