Which way will the equilibrium shift when subjected to the following changes? 2NOBr + heat <-> 2NO +Br2?
NO is addded
temp. doubled
Br2 removed
Pressure increased
I said: reverse, forward, forward, forward
Correct on a,b,c.
I don't know on D.
When pressure is increased the reaction shifts to the side with fewer GAS moles. You didn't write the phases. If Br2 is a liquid, increasing P will have no effect since there are 2 moles on each side; if Br2 is a gas, the rxn will shift to the left for increase in P (2 mols on left vs 3 on right).
To determine how the equilibrium will shift when subjected to certain changes in the reaction 2NOBr + heat ↔ 2NO + Br2, you need to consider Le Chatelier's principle. This principle states that when a system at equilibrium is subjected to a change, it will respond to counteract that change and reestablish a new equilibrium.
Let's analyze each change and its effect on the equilibrium:
1. NO is added:
When NO is added to the reaction, it increases the concentration of one of the reactants. According to Le Chatelier's principle, the equilibrium will shift in the direction that consumes this added substance. In this case, NO is a reactant, so the equilibrium will shift forward to consume the additional NO. Therefore, the equilibrium will shift forward.
2. Temperature doubled:
Doubling the temperature affects the equilibrium through the heat term in the reaction equation. Increasing the temperature adds thermal energy to the system. According to Le Chatelier's principle, when the temperature increases, the equilibrium will shift in the direction that absorbs the excess heat. The forward reaction is exothermic, meaning it releases heat. Thus, by increasing the temperature, the equilibrium will shift in the reverse direction to absorb the excess heat. Therefore, the equilibrium will shift in the reverse direction.
3. Br2 removed:
When Br2 is removed from the reaction, it decreases the concentration of one of the products. According to Le Chatelier's principle, the equilibrium will shift in the direction that produces more of the substance that has been removed. In this case, by removing Br2, the equilibrium will shift forward to produce more Br2. Therefore, the equilibrium will shift forward.
4. Pressure increased:
In this reaction, there are equal numbers of moles on both sides of the equation. Increasing the pressure does not favor any side based on the gas volume. Therefore, changing the pressure will not induce a shift in the equilibrium. The system will remain at equilibrium, and no shift will occur.
Based on the analysis:
- When NO is added, the equilibrium will shift forward.
- When the temperature is doubled, the equilibrium will shift in the reverse direction.
- When Br2 is removed, the equilibrium will shift forward.
- When the pressure is increased, there will be no shift in the equilibrium.
Therefore, the correct answer is: forward, reverse, forward, no shift.