0:02 now we're going to think about some
0:04 related kind of terms
0:06 so thermal energy is some sort of
0:08 kinetic energy
0:16 or molecules so how fast are things
0:17 moving around
0:20 temperature on the other hand is a quantitative
0:22 quantitative
0:26 measure of of how hot
0:30 or cold something is
0:32 so i like to think about this in this
0:34 kind of a diagram down here
0:37 is that a hot liquid will have a higher temperature
0:38 temperature
0:39 and the reason it has a higher
0:41 temperature is because all the atoms in
0:42 there are moving
0:45 faster and faster and then when you cool
0:47 it down the atoms start moving
0:50 a lot slower so that is the difference
0:52 between temperature
0:55 and thermal energy is thinking about how
0:57 what happens in a hot liquid versus a
0:58 cold liquid
1:00 so how fast are the things that are
1:02 moving around
1:04 heat is what we're going to be really
1:05 concerned about and we're going to call
1:07 this q
1:10 and this is the transfer
1:16 so we can have different kind of
1:18 transfers that happens from something
1:20 going from hot to something going colder
1:22 so remember when things get
1:24 warmer all the atoms inside are actually
1:26 vibrating a little bit faster
1:28 are moving around a little bit faster so
1:31 this can happen in a solid liquid
1:34 or a gas so in terms of chemistry what
1:36 we're really going to look at
1:40 is our reactions and how they produce
1:44 heat and we'll give this heat uh
1:47 term a name uh later so we can think
1:50 about it exothermic reaction
1:55 and an exothermic reaction releases heat
1:58 so you can think about this as an a
1:59 going to b
2:03 and heat is on the product
2:05 side and we can feel this heat that's
2:06 coming off it'll feel
2:10 hot to us an endothermic
2:18 so our reactant actually requires some
2:23 and something like this an endothermic
2:24 reaction will
2:27 feel cold because it's actually sucking
2:28 the heat
2:32 out of our hand into the reaction itself
2:34 so some examples of an exothermic reaction
2:35 reaction
2:38 are things like combustion
2:41 kind of reactions so this is when we
2:42 burn something so if you take an
2:44 acetylene oxygen torch
2:46 and you burn it you end up getting heat
2:48 out and that's how we do a lot of our welding
2:49 welding
2:52 and cutting for the the steel and metals industry
2:53 industry
2:55 and something that's endothermic that
2:56 you might be familiar with if you've
2:58 ever gotten hurt
2:59 doing some activity you might have
3:01 gotten an ice pack
3:05 and uh and in these kinds of reactions
3:07 we are going to take something like
3:09 ammonium nitrate
3:12 and that ends up dissolving
3:14 in the water so you have to smash it so
3:16 that you can break out the water
3:19 and mix it with the ammonium nitrate and
3:20 as it dissolves
3:24 it absorbs heat so it feels
