Question

Use Le Châtelier’s Principle to predict the shift in equilibrium (Left, Right, No Change) for each of the following:

REACTIONS:

A. CH4(g) + 2 O2(g) ⇌ CO2(g) + 2 H2O(g) ΔH = -230 kJ

4 Al(s) + 3 O2(g) ⇌ 2 Al2O3(s) + 150 kJ

C. N2(g) + 3 H2(g) ⇌ 2 NH3(g) ΔH = + 22 kJ

D. 2 H2O(l) + 58 kJ ⇌ 2 H2(g) + O2(g)

_____ 1. Pressure decrease for reaction A
_____ 2. Pressure increase for reaction B
_____ 3. Adding heat in reaction C
_____ 4. Decreasing heat in reaction D
_____ 5. Increasing [N2] in reaction C
_____ 6. Decreasing [H2O] in reaction D
_____ 7. Adding heat in reaction A
_____ 8. Pressure increase for reaction D
_____ 9. Increasing [Al2O3] in reaction B
_____ 10. Pressure decrease for reaction C
_____ 11. Decreasing [CO2] in reaction A
_____ 12. Decreasing heat in reaction B
_____ 13. Addition of a catalyst to reaction B
_____ 14. Increasing [O2] in reaction B
_____ 15. Pressure increase for reaction C

Answer 1

1. Right
2. No Change
3. Left
4. Right
5. Right
6. Left
7. Left
8. No Change
9. No Change
10. Right
11. Left
12. Right
13. No Change
14. No Change
15. Left

Step-by-step explanation:

1. According to Le Châtelier's Principle, a decrease in pressure favors the side with fewer moles of gas. In this case, the reaction will shift to the right to produce more gaseous products and decrease the pressure.

2. Increasing the pressure of a reaction favors the side with fewer moles of gas. In this case, there is no change in the number of moles of gas on either side of the reaction, so the equilibrium position will not shift.

3. Adding heat to an exothermic reaction (one with a negative ΔH value) will shift the equilibrium to the left to absorb the excess heat.

4. Decreasing heat in an endothermic reaction (one with a positive ΔH value) will shift the equilibrium to the left to generate more heat.

5. Increasing the concentration of a reactant will shift the equilibrium to the right to counteract the increase.

6. Decreasing the concentration of a reactant will shift the equilibrium to the left to counteract the decrease.

7. Adding heat to an exothermic reaction (one with a negative ΔH value) will shift the equilibrium to the left to absorb the excess heat.

8. Increasing the pressure of a reaction favors the side with fewer moles of gas. In this case, there is no change in the number of moles of gas on either side of the reaction, so the equilibrium position will not shift.

9. Adding product to a reaction will not shift the equilibrium position, according to Le Châtelier's Principle.

10. Decreasing the pressure of a reaction favors the side with more moles of gas. In this case, the reaction will shift to the right to produce more gas and increase the pressure.

11. Decreasing the concentration of a product will shift the equilibrium to the right to counteract the decrease.

12. Decreasing the temperature of an endothermic reaction (one with a positive ΔH value) will shift the equilibrium to the right to generate more heat.

13. Adding a catalyst will not shift the equilibrium position, according to Le Châtelier's Principle.

14. Increasing the concentration of a reactant will not shift the equilibrium position, according to Le Châtelier's Principle.

15. Increasing the pressure of a reaction favors the side with fewer moles of gas. In this case, the reaction will shift to the left to decrease the number of gaseous molecules and decrease the pressure.