Answer:
1. The concentration of Nâ‚‚Oâ‚„ decrease as the temperature of the system increased.
2. The formation of products was favored by the addition of heat.
3. The reaction going from right to left is exothermic.
4. N₂O₄ → 2NO₂; HR = +14 kcal.
Explanation:
Equation of the reaction is as follows: N₂O₄ ⇄ 2NO₂
The forward reaction proceeds with an increase in temperature. As the temperature of the reaction was increased, more of the Nâ‚‚Oâ‚„ decomposed to form NOâ‚‚. Therefore, the concentration of Nâ‚‚Oâ‚„ deceased.
2. The formation of products, that is the forward reaction leading to formation of NOâ‚‚ was favored by the addition of heat. Thus, with increase in temperature, the concentration of NOâ‚‚ increased.
3. An endothermic reaction is a type of reaction which requires energy input in the form of heat in order to proceed.
From the observations during the reaction, an increase in temperature by the addition of heat resulted in an increase in the forward reaction, therefore, the forward reaction is endothermic and the backward reaction is exothermic. Thus, the reaction in which colorless Nâ‚‚Oâ‚„ is produced, is an exothermic reaction.
4. The change in enthalpy of a reaction is the difference in the heat content of reactants and products. For exothermic reactions, enthalpy change is negative, whereas for endothermic reactions, enthalpy change is positive.
The decomposition of  N₂O₄ to NO₂ is an endothermic reaction. Hence, the correct chemical equation is: N₂O₄ → 2NO₂; HR = +14 kcal.
