Question

Dinitrogen tetraoxide and nitrogen dioxide are two gases that exist in equilibrium at a range of temperatures. NO2 is a reddish brown gas while N2O4 is colorless. ... At High Temperature the red color is strong. ... ... At Low Temperature the gas has less color. ... If we represent the equilibrium as:... 2 NO2(g) N2O4(g)
If we represent the equilibrium as:... 2 NO2(g) Doublearrow.GIFN2O4(g)
We can conclude that:

This reaction is:

A. Exothermic
B. Endothermic
C. Neutral
D. More information is needed to answer this question.

Answer 1

Answer:

A. Exothermic

Explanation:

Let's consider the following reaction at equilibrium.

    2 NO₂(g)       ⇄      N₂O₄(g)

reddish brown         colorless

In order to assess the effect of temperature on the equilibrium, we need to consider Le chatelier's principle: If a system at equilibrium suffers a perturbation, it will shift its equilibrium position to counteract such perturbation.

Let's suppose the reaction is exothermic.

• If we decrease the temperature, the system will try to increase it by favoring the forward reaction to release heat. As a consequence, more colorless N₂O₄ is produced.
• If we increase the temperature, the system will try to decrease it by favoring the reverse reaction to absorb heat. As a consequence, more reddish brown NO₂ is produced.

Since it coincides with the experimental results, we can conclude that the reaction is exothermic.