Activity 2 Le Châtelier\'s Principle PDF

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Activity 2: Le Châtelier's Principle 1. What is the effect of an increase in pressure on each of the systems described by the following reactions? 1.

The reaction will shift towards left

2.

The reaction will shift towards right

3.

The reaction will shift towards left

4.

The reaction will not change because there are no gasses in the reaction.

5.

The reaction will not change because there are no gasses in the reaction.

2. During the industrial synthesis of methanol (CH3OH), carbon monoxide (CO) reacts with hydrogen gas. For methanol, ΔH= -100.4 kJ/mol. 1. Write the balanced chemical equation for this reaction. CO(G) + 2H2(g) → CH3OH(I)

DELTA H= 100.4 kJ/mol

2. Is it better to maintain this system at a low or high temperature, to obtain a good output? The reaction is exothermic, so it will be better to maintain a low temperature. This way the system will counteract the low temperature and try to increase it, consequently forcing the reaction to the right and creating more methanol 3. Is it preferable to maintain this system at high or low pressure? Explain. It is optimal to maintain a high pressure since there are 3 mol of gases on the left and O mol of gases on the right

3. The following phase change has reached equilibrium in a closed system:

1. What is the effect of a reduction of volume by increasing the pressure? If the volume is decreased, the reaction will tend towards the side with the latest amount of moles of gases. There are o mol on the left side and on the right side there is one mol of gasses. Therefore, the reaction will tend to the left side 2. What is the effect of an increase in temperature? A higher temperature increases the heat term on the left. The system will counteract and try to reduce the temperature by making the reaction tend to the right side 3. What is the effect of injecting some steam into the closed system, thus raising the pressure? Assume no temperature change. Steam is H2O. If it is added, the reaction will tend towards the left side, also the increase in pressure caused by the steam will make the reaction towards the side of the lowest number of moles, the left side. The reaction will tend towards the left side 4. Consider the system described by the following reaction:

What effect would the following changes have on the concentration of the substances at equilibrium? Use Le Châtelier's principle to support your answers. 1. The temperature of the container used for the reaction decreases. ● The system counteracts the change and wants to increase Q ● The q is on the right side of the reaction ● The reaction will tend to go from the left side to the right side ● [C2H6] and [O2] decreases and [CO2], [H2O] increases

2. The pressure increases. ● The system counteracts the change and wants to decrease the pressure. ● There are 9 mol of gases on the left and 4 mol of gases on the right. ● The reaction will tend to go from the left side to the right side. ● [C2H6] and [O2] decrease and [CO2], [H2O] increase. 3. A catalyst is added. ● The system reaches equilibrium faster. ● No side is favoured by adding a catalyst, but the equilibrium is reached faster. ● all concentrations remain unchanged. 4. The volume of the container increases. ● The system counteracts the change and wants to decrease the volume. ● There are 9 mol of gases on the left and 4 mol of gases on the right. ● The reaction will tend to go from the right side to the left side. ● [C2H6] and [O2] increase and [CO2] ● [H2O] decrease. 5. [CO2] increases. ● The system counteracts the change and wants to decrease [CO2]. ● The [CO2] is on the right side of the reaction. ● Tend to go from the right side to the left side. ● [C2H6] and [O2] increase and [H2O] decreases. ● [CO2] also increases since it was added. 5. Using Le Châtelier's principle, explain what happens if Fe3+ (aq) ions are added to the following reaction:

● The system counteracts the change and wants to decrease [Fe3+]. ● The Fe3+ is on the left side of the reaction. ● Tend to go from the left side to the right side.

● [Fe3+] and [FeSCN2+] increase ● [SCN-] decreases....