Now it is time to practice applying Le Chatelier’s Principle. Look at the reaction on each tab, then answer the questions that follow.
When baking soda is dissolved in water, it decomposes into carbon dioxide gas and aqueous sodium hydroxide according to this equation:
NaHCO3 (aq) ⇌ CO2 (g) + NaOH (aq) + heat
Answer the following questions about the reaction shown above. For each stress described, determine whether the equilibrium will shift in the reverse direction (to make more reactants), shift in the forward direction (to make more products), or not shift at all.
If the system is open to the air, the carbon dioxide will dissipate out of the solution. Which direction will the equilibrium shift as the concentration of CO2 decreases?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When [CO2] decreases, the equilibrium will shift to make more products to make up for the deficit.
When [CO2] decreases, the equilibrium will shift to make more products to make up for the deficit.
When [CO2] decreases, the equilibrium will shift to make more products to make up for the deficit.
Which direction will the equilibrium shift if the reaction is heated (i.e., the temperature increases)?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When the temperature increases due to the addition of more heat, the reaction will shift in the endothermic direction, which will use up the excess heat energy.
When the temperature increases due to the addition of more heat, the reaction will shift in the endothermic direction, which will use up the excess heat energy.
When the temperature increases due to the addition of more heat, the reaction will shift in the endothermic direction, which will use up the excess heat energy.
If the gas pressure of the system is increased, which direction will the equilibrium shift?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When the pressure increases, the reaction will shift towards the side with fewer gas molecules (0 vs 1) to lower the overall pressure.
When the pressure increases, the reaction will shift towards the side with fewer gas molecules (0 vs 1) to lower the overall pressure.
When the pressure increases, the reaction will shift towards the side with fewer gas molecules (0 vs 1) to lower the overall pressure.
Which direction will the equilibrium shift if a catalyst is added to the reaction?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When a catalyst is added, the rate of the reaction will increase. Because this rate increases equally in both the forward and reverse directions, no equilibrium shift will occur.
When a catalyst is added, the rate of the reaction will increase. Because this rate increases equally in both the forward and reverse directions, no equilibrium shift will occur.
When a catalyst is added, the rate of the reaction will increase. Because this rate increases equally in both the forward and reverse directions, no equilibrium shift will occur.
Summary
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When water undergoes electrolysis, it decomposes into its component gases, hydrogen and oxygen, according to this equation:
heat + 2H2O (l) ⇌ 2H2 (g) + O2 (g)
Answer the following questions about the reaction shown above. For each stress described, determine whether the equilibrium will shift in the reverse direction (to make more reactants), shift in the forward direction (to make more products), or not shift at all.
If the temperature of the system is decreased, how will the equilibrium of the reaction shift?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When the temperature decreases, the reaction will shift in the exothermic direction, which will produce more heat energy to make up for the deficit.
When the temperature decreases, the reaction will shift in the exothermic direction, which will produce more heat energy to make up for the deficit.
When the temperature decreases, the reaction will shift in the exothermic direction, which will produce more heat energy to make up for the deficit.
Which direction will the equilibrium shift if the size of the container expands (which will cause the gas pressure to decrease)?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When the pressure decreases, the reaction will shift towards the side with more gas molecules (3 vs 0) to increase the overall pressure.
When the pressure decreases, the reaction will shift towards the side with more gas molecules (3 vs 0) to increase the overall pressure.
When the pressure decreases, the reaction will shift towards the side with more gas molecules (3 vs 0) to increase the overall pressure.
If more oxygen gas is added to the system, how will the equilibrium of the reaction shift?
- shift left (towards reactants in reverse direction)
- shift right (towards products in forward direction)
- no shift (equilibrium is unchanged)
When the concentration of oxygen increases, the reaction will shift left (in the reverse direction) to use up the excess products and make more reactants.
When the concentration of oxygen increases, the reaction will shift left (in the reverse direction) to use up the excess products and make more reactants.
When the concentration of oxygen increases, the reaction will shift left (in the reverse direction) to use up the excess products and make more reactants.
Summary
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