00:01
Hello everyone, so the first part of the question asks us the concentration after 158 minutes of a first order reaction.
00:09
So, we have n equal to 1 first order reaction, the value of rate constant k which is 0 .00025 per second and the time is 158 minutes and the initial concentration say ca0 is 6 .19 m.
00:41
So, we know that for a first order reaction the rate constant k equals 1 divided by t natural log of ca0 divided by ca which is the concentration at time t.
00:58
So, from here we can calculate we have 0 .00025 this is per second 1 divided by time which is 158 minutes.
01:10
So, need to convert it into seconds.
01:12
So, we will multiply it with 60 seconds and then we will have ln of 6 .19 divided by ca and when we calculate it we get the value of ca as 0 .58 m.
01:31
So, the concentration of a after 158 minutes will be 0 .58 molar.
01:50
The second part of the question asks us to calculate the time to reach the same concentration of 0 .58 m if it were a second order reaction.
01:59
So, for that case if n equal to 2 then k would be equal to 1 divided by t we will have 1 divided by ca subtracted with 1 divided by ca0...