The meaning of Half-Life time is easy: Time needed to make a chemical substance becomes half-part of it on a reaction.
To determine the equation of half-life time, we have to use the integrated equation of rate of reaction and of course the coefficient and the order of reaction of substances.
For example, Determine the half-life time equation for first order of reaction for this reaction: aA(g) --> B(g)
From my previous post about Integrated Equation of Rate of Reaction, we already found the equation for first order reaction.
Okay, now we’ve found the one we were searching for. Now, I will give you the formula of half-life time reaction for the order of reaction of 'n' with 'n' is not equal to 1.
Example of Question:
Determine the half-life time of the reaction of: 2 N2O5(g) --> 4 NO2(g) + O2(g) at 45oC if the rate of reaction constant of it is 3,115 x 10-4 s-1 and the order of reaction of that reaction is one! (Answer: 1112,6 s)