For a certain gas-phase reaction, the fraction of products in an equilibrium mixture is increased by either increasing the temperature or increasing the volume of the reaction vessel. complete the sentences to determine if the reaction is endothermic or exothermic and to determine which side of the equation has more molecules.

Hello!

First, we can model the chemical reaction in the following way:

nA(g) ⇄ mB(g)

Now, we can start answering the two questions:

 1) Determine if the reaction is endothermic or exothermic:

The reaction is endothermic. We know that because the fraction of products is increased when the temperature is increased. According to Le Chatelier's principle, the system will move in the opposing direction of the changes to establish a new equilibrium. We can model an endothermic reaction in the following way, knowing that it needs heat to be completed

nA(g) + Δ ⇄ mB(g)

So, adding heat in the left side of the reaction will displace the equilibrium in the opposing direction (the right side) increasing the fraction of products.

2) Determine which side of the equation has more molecules:

The right side of the equation has more molecules than the left side. According to Le Chatelier's Principle, in a gas phase reaction, increasing the volume results in a decrease in the internal pressure of the system, so the reaction shifts to the side with more molecules to restore the pressure of the system. As the fraction of products increases with the increase in volume, the right side will have more molecules. We can then express this reaction in the following way:

nA(g) ⇄ mB(g)  n<m

Have a nice day!

I’m guessing you’re more alert to yourself or your surroundings if you’re more concentrated