00:01
So let's talk a little bit about energy.
00:04
In this unit, you're going to be looking at a lot of different definitions, and you might be thinking that heat and energy are interchangeable, and in fact, they're not.
00:15
So let's make sure we understand what energy is.
00:19
And energy is really just a property of matter when that matter has the ability to do work.
00:37
And so when we talk about work in a chemistry context, most of the time that work is going to be found in terms of changing volume at a given pressure.
01:03
And so delta means change.
01:06
And we have p for pressure and v for volume.
01:09
So if matter can actually do that, it has energy.
01:16
So i'd like you to think about a rocket ship at this point.
01:23
And so in my crude drawing of a rocket, the rocket is going to have a whole bunch of fuel in it.
01:40
And that fuel could be hydrazine, or it could be as simple as hydrogen and oxygen, but it's got fuel.
01:51
And when we go ahead and ignite that fuel, a couple of things happen, we're going to release a lot of heat, but we're also going to change the volume of gases and actually have a whole bunch of gas also come out of the rocket.
02:10
That is going to change the volume of that chemical reaction system, and thus we're going to do some work.
02:22
That's where the energy in rocket fuel comes from...