Now, if we remember, we have done this in a previous lesson.

If we're dealing with gases, and

we know that PV=nrt, we could put our n and

our V together and get P equals n over V times RT.

This that I'm circling are the units of concentration.

So there is a relationship between concentration and pressure.

So all the same plots, linear expressions,

could be obtained using pressure instead of concentration.

So we could plot natural log of pressure versus time and

also get a straight line if it's first order kinetics.

Here is a depiction of this, natural log of pressure versus time for

this generic reaction where I've got an A that's a gas.

It would also give me a nice straight line.

Well that's the end of our learning objective five,

where we're looking at only first order kinetics.

We're looking at that integrated rate law for it, we haven't yet

done any calculations with it, but

you might have to do some, get some information from graphs.

And if you ever see a straight line plot, or natural log of pressure or

concentration is plot along with the Y-axis and time along the X-axis.

Whenever you see a straight line,

you will automatically know that's a first-order reaction.