How will the equilibrium: Heat energy + CH4 + 2H2S = CS2 + 4H2 be affected by the following?
a) A decrease in temperature?
b) The addition of H2
c) The removal of some CH4
d) An increase in the volume of the container
e) The addiotion of a catalyst.
i know that [CH4] goes up
[H2S] goes up
[CS2]goes down
and [H2] goes down.
e) is no change.
But why do these shift? that's where i am confused.
To understand how these changes affect the equilibrium, we can apply Le Chatelier's principle, which states that if a system at equilibrium is subjected to a change, it will shift in a way that counteracts the effect of that change.
a) Decrease in temperature: When the temperature decreases, it can be considered as a stress on the system. According to Le Chatelier's principle, the system will shift in a way to counteract the decrease in temperature. Since heat is treated as a reactant in this equilibrium, the reaction will shift towards the side that produces heat, which means it will shift towards the right side (products side). This results in an increase in CS2 and H2 production and a decrease in CH4 and H2S.
b) Addition of H2: When you add more H2 to the system, it affects the ratio of reactants to products. According to Le Chatelier's principle, the system will shift in a way to counteract the increase in H2 concentration. Since H2 is a product in this equilibrium, the reaction will shift towards the left side (reactants side). This leads to a decrease in CS2 and H2 concentration and an increase in CH4 and H2S.
c) Removal of some CH4: When you remove CH4 from the system, it affects the ratio of reactants to products. According to Le Chatelier's principle, the system will shift in a way to counteract the decrease in CH4 concentration. Since CH4 is a reactant in this equilibrium, the reaction will shift towards the right side (products side). This causes an increase in CS2 and H2 production and a decrease in CH4 and H2S.
d) Increase in the volume of the container: Increasing the volume of the container is equivalent to decreasing the pressure. According to Le Chatelier's principle, the system will shift in a way to counteract the decrease in pressure. Since there are four moles of gas molecules on the product side and only three moles on the reactant side, the reaction will shift towards the side with more moles of gas to compensate. Thus, it will shift towards the left side (reactants side), resulting in a decrease in CS2 and H2 concentration and an increase in CH4 and H2S.
e) Addition of a catalyst: A catalyst does not directly affect the equilibrium position. It increases the rate of the forward and reverse reactions equally, allowing the equilibrium to be reached faster. The addition of a catalyst does not cause any shift in the equilibrium concentrations of the reactants and products.
Overall, Le Chatelier's principle helps us understand how changes in temperature, pressure, concentration, and the addition of catalysts can affect the equilibrium position of a reaction. By considering the effects of such changes, we can predict how the system will respond and shift to reach a new equilibrium.