anilrai1984kumar

The reaction A   P is first order reaction with respect of [A]. Consider the following data.  

Time (s)      [A] mol/L      

0                 1.60

10               0.40

20               0.10  

The half-life of this reaction is...

◯ 20 s ◯ 5 s ◯ 10 s ◯ 30 s

I know it is 5 seconds, but please show the steps on how you figure out it is 5 seconds. How can I myself find 5 seconds?

How many countries are there in the world?