For the chemical reactiom to be at equilibrium:
1- The rate of forward reaction must be equal to the rate of the reverse reaction.
2- The mass of EACH element must be equal before and after the reaction (no NET change in mass), otherwise the equilibrium will shift.
Important note: you need to check the mass of each element before and after the reaction (i.e, reactants side and products side) and the not the mass of the system as a whole. This is because the mass of the whole system will be preserved whether the system is at equilibrium or not (this is the fundamental law of mass conservation)
The overall reaction is given by:
The fast step reaction is given as:
The slow step reaction is given as:
(slow step )
Now, the expression for the rate of reaction of fast reaction is:
The expression for the rate of reaction of slow reaction is:
Slow step is the rate determining step. Thus, the overall rate of formation is the rate of formation of slow reaction as takes place in this reaction.
The expression of rate of formation is:
= (1)
Now, consider that the fast step is always is in equilibrium. Therefore,
Substitute the value of in equation (1), we get:
=
=
Thus, rate law of formation of in terms of reactants is given by .
Answer:
2.48626 x 10^24
Explanation:
We multiple 4.13 by avogadro's number to get that.