Now we're going to look at different methods that involve half life in some way. In method one, we're dealing with the direct calculation of half life or rate constant. Now, in method one, you use a radioactive half life equation when dealing with only the half life and the decay constant, which is K.
Now here the formula for the radioactive half life is:
t = ln 2 KLane two is a constant which is equal, if you plug into your calculator, to approximately 0.693. K Here's our decay constant, which is in times inverse, which shouldn't be mistaken with time, which is T.
Here, when it comes to a plot of half life versus time, we would say that half life does not depend on the initial concentration because if we look, we don't see this variable within the formula and it is constant through the whole reaction. Remember the example that we saw earlier? Every three days we'd lose half of our starting material. It was every three days. It didn't fluctuate where it's 2.5 here and 1.8 here or 7.2 here. It was always three days because of that.
Well, if we were to plot this, we'd say that the half life remains flat. It's constant. So no matter how much time passes, my half life stays the same. So it would just be this flat straight line. O when it comes to the radioactive half life equation. Just remember this is the equation we utilize. It forms a connection between half life and our decay constant K. Half life is a constant idea because we're following first order rate law rules.