Given the following reaction:
3 H2(g) + N2(g) <- -> 2NH3(g) + heat
If the following changes were to occur what direction shift will it have (left or right)
And what will be the reason of the shift
Changes/Stress on system:
Adding NH3
Decreasing the pressure
Adding heat
Removing N2
Increasing the pressure
In common words, Le Chatelier's Principle tells us that when a system in equilibrium is subjected to a stress, it will shift to undo what we did to it.
So look at the equation.
3 H2(g) + N2(g) <- -> 2NH3(g) + heat
Adding NH3. So the reaction will try to use up NH3 to get rid of what we added. How can it do that? Shift to the left.
When increasing P, the reaction shifts to the side with fewer mols.
See if you can finish.
so when you increase p does that mean it shifts to the left
No i think its to the right
That's right. Increasing P shifts to the side with fewer mols OF GAS. There are 4 mols on the left and 2 on the right so increasing P shifts to the right; decreasing P shifts it to the left.
To determine the direction shift (left or right) and the reason for the shift in each scenario, we need to consider Le Chatelier's principle. According to this principle, when a system at equilibrium is subjected to a stress or change, it will shift in a direction that minimizes the effect of the change. Let's analyze each scenario:
1. Adding NH3:
When NH3 is added to the system, the equilibrium will shift to the left to consume some of the NH3. This is because an increase in the concentration of reactants leads to a shift in the direction that decreases the concentration of the added component.
2. Decreasing the pressure:
We can interpret decreasing the pressure as increasing the volume. When the pressure is decreased, the equilibrium will shift to the side with more moles of gas to compensate for the change. In this case, the right side of the reaction has fewer moles of gas. Therefore, the equilibrium will shift to the right to produce more gas molecules (NH3).
3. Adding heat:
If heat is added to an exothermic reaction like this one, the equilibrium will shift to the left to consume heat. The reaction is exothermic because heat is written as a product. Increasing the temperature, in this case, will favor the endothermic direction (opposite to the direction of heat).
4. Removing N2:
Removing N2 disrupts the balance between reactants and products. In response, the equilibrium will shift to the right to produce more N2, thus replacing the removed amount.
5. Increasing the pressure:
Increasing the pressure is equivalent to decreasing the volume of the system. According to Le Chatelier's principle, the equilibrium will shift to the side with fewer moles of gas to offset the increase in pressure. In this case, the left side has fewer moles of gas. Thus, the equilibrium will shift to the left to reduce the pressure.
By considering Le Chatelier's principle for each scenario, we can determine the direction shift and the reason behind it.