HELP WiiTH CHEMiiSTRY?

Question

Given the reaction at equilibrium:
N2(g) + 3H2(g) <--> 2NH3(g) = heat
At constant temperature, which changes would produce a greater yield of NH3(g)?

a- decreasing the pressure and decreasing the concentration of N2(g)
b- increasing the pressure and decreasing the concentration of N2(g)
c- increasing the pressure and increasing the concentration of N2(g)
d- decreasing the pressure and increasing the concentration of N2(g)

thanks in advance =)

Answer 1

[Answer: C]

We can use Le Chatelier's principle here.
Since there are fewer gas molecules here, if you increase the pressure (decrease volume), the equilibrium will shift right (towards the side with fewer gas molecules), thus increasing the [NH3].
If we increase the [N2], then by the principle, the equilibrium will shift right as well in order to counteract the affects of adding more [N2] in order to re-establish equilibrium.

Answer 2

C, increase the pressure and increase the concentration.

Remember Le Châtelier's principle : If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or total pressure, then the equilibrium shifts to partially counter-act the imposed change.

If you increase the concentration of N2, the equilibrium will shift to the right. Thus, the more product will be made.

Now, let's increase the pressure. Let's assume that we are increasing the total pressure of the system by decreasing the volume (Boyle's Law).

According to Le Châtelier's principle the equilibrium would move to decrease the pressure. Noting that 4 moles of gas occupy more volume than 2 moles of gas, we can deduce that the reaction will move towards the products if we were to increase the pressure.

Thus, an increase in pressure causes the reaction to shift to the side with the fewer moles.

So, increasing the pressure and increasing the concentration of N2 will shift the equilibrium to the right.

I hope this helps.