00:01
In this question we want to determine the rate of disintegration and this is going to be the final number of atoms multiplied by decay.
00:10
So for us to determine our k, we're going to assume first order decay kinetics, which says our n is equal to the initial number of atoms multiplied by the exponent of negative k -tim.
00:24
Where k is this value that we are looking for to blacking into this formula and then determine.
00:30
Our rate of decay our n this is what we're going to be calculating here after a certain time t so the first thing that we have to do here is to look at the half life because we know our k is equal to link 2 divided by t half so if we look for a half life which is 21 hours it means per day our k is going to be linked 2 divided by 21 hours divided by so our k is going to be equal to 0 .792 and the units are going to be per day.
01:12
Now that we have our k, we just need to determine the initial number of atoms, that is, n -knot.
01:22
So for us to do this, we have to look for the number of moles because we know, according to avocados law, any one mole of any substance, it contains 6 .022 multiplied by 10 to the power 23 particles.
01:40
So if we can determine the number of moles, the initial number of moles, and multiply this by avocatrous constant, that is going to give us the initial number of atoms.
01:52
And then moving on, let's determine the initial number of moles...