Reversible reaction is a reaction that can be occured in two directions, forward reaction and back (reverse) reaction. These reactions are happened at the same time.
Imagine a reaction : A(s) + B(aq) = C(aq) + D(g). This is in a closed system. We can think by using their color, for example B =blue and C = orange. At the same time blue --> orange and orange --> blue.
If the blue form turns into the orange one much faster than the the other one, so after the equilibrium can be achieved, the blue one becomes light and the orange one becomes dark. If this condition doesn't change again, the macroscopic change isn't happened but there is a dinamic change which is still occured constanously. This called a microscopic change and this reversible reaction named as a dynamic equilibrium.
Position of equilibrium
In the example above, the equilibrium mixture contained more orange than the blue ones. We can say :
"The position of equilibrium lies towards the orange."
"The position of equilibrium lies towards the right-hand side."
If the conditions of the experiment change (by adding reactant or product, so the macroscopic change will happen again), the composition of the equilibrium mixture will also change, till the equilibrium can be achieved.
Thinking about reaction rates
At the beginning of the reaction, the concentrations of A and B are at the maximum. The rate of the reaction is at its fastest.
As A and B react, their concentrations decrease, and the rate of the forward reaction falls as ti
me goes on. At the same time, the concentration of C and D increases, and the rate of reverse reaction increases. At the equilibrium the rate of forward reaction= the rate of reverse reaction. (v1 = v2)
In summary, at equilibrium, the quantities of everything present in the mixture remain constant, although the reactions are still continuing. This is because the rates of the forward and the reverse reactions are equal.
If you change the conditions in a way which changes the relative rates of the forward and reverse reactions you will change the position of equilibrium or change the proportion of the subtances.
The charactheristic of dynamic equilibrium are :
1. Closed system
2. rate of forward reaction = rate of reverse reaction
3. Dynamic microscopic change
4. Constant proportion of substances
Imagine a reaction : A(s) + B(aq) = C(aq) + D(g). This is in a closed system. We can think by using their color, for example B =blue and C = orange. At the same time blue --> orange and orange --> blue.
If the blue form turns into the orange one much faster than the the other one, so after the equilibrium can be achieved, the blue one becomes light and the orange one becomes dark. If this condition doesn't change again, the macroscopic change isn't happened but there is a dinamic change which is still occured constanously. This called a microscopic change and this reversible reaction named as a dynamic equilibrium.
Position of equilibrium
In the example above, the equilibrium mixture contained more orange than the blue ones. We can say :
"The position of equilibrium lies towards the orange."
"The position of equilibrium lies towards the right-hand side."
If the conditions of the experiment change (by adding reactant or product, so the macroscopic change will happen again), the composition of the equilibrium mixture will also change, till the equilibrium can be achieved.
Thinking about reaction rates
At the beginning of the reaction, the concentrations of A and B are at the maximum. The rate of the reaction is at its fastest.
As A and B react, their concentrations decrease, and the rate of the forward reaction falls as ti
me goes on. At the same time, the concentration of C and D increases, and the rate of reverse reaction increases. At the equilibrium the rate of forward reaction= the rate of reverse reaction. (v1 = v2)In summary, at equilibrium, the quantities of everything present in the mixture remain constant, although the reactions are still continuing. This is because the rates of the forward and the reverse reactions are equal.
If you change the conditions in a way which changes the relative rates of the forward and reverse reactions you will change the position of equilibrium or change the proportion of the subtances.
The charactheristic of dynamic equilibrium are :
1. Closed system
2. rate of forward reaction = rate of reverse reaction
3. Dynamic microscopic change
4. Constant proportion of substances
No comments:
Post a Comment