00:01
What is the half -life of n205? since we have a first -order reaction, we use our expression, negative d -d -t of ca equal to k -ca.
00:14
And so, ca is equal to pa divided by rt.
00:22
And so we have negative d -p -a -d -t equal to k -p -a.
00:29
When we can integrate this, we get negative ln, of pa divided by pao equal to kt, where pa is our partial pressure at time t, pao is our initial pressure, and k is our rate constant.
00:47
So if pa is 0 .5po, then the time of our half -life, negative ln of 0 .5, is equal to k times our half -life.
00:59
And so our half -life is equal to 0 .693 divided by 3 .3 .3.
01:07
Times 10 to the negative 5, which is 0 .00, or which is equal to 205 .03 seconds.
01:25
Then we're asked one for 10 seconds...