To determine the direction in which the reaction shifts when heated up, we need to apply Le Chatelier's Principle. This principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
Let's take a close look at the given reaction:
[tex]\[
2 NO (g) + H_2 (g) \rightleftharpoons N_2O (g) + H_2O (g) + \text{heat}
\][/tex]
From the reaction, we can see that heat is a product of the reaction. This indicates that the reaction is exothermic, meaning it releases heat as it proceeds in the forward direction.
When we increase the temperature by heating the system, we are adding more heat. According to Le Chatelier's Principle, the system will try to counteract this change by consuming the added heat. It does this by shifting the equilibrium position to the side that absorbs heat.
In an exothermic reaction, the reverse reaction (from products to reactants) absorbs heat. Thus, when we heat the system, the equilibrium will shift to the left, towards the reactants, to absorb the excess heat.
Therefore, the correct answer is:
C. The reaction shifts left or to reactants.
