in this video, we're going to begin our lesson on the thermal properties of water. And so to understand the thermal properties of water, we need to understand kinetic energy and so kinetic energy is really just a measure of energy in the form of motion. And so if substances are moving, that means that they have kinetic energy. It's really the energy of motion. Now, temperature is a term that we've all heard before in our past. And really, temperature is just defined as the average kinetic energy of molecules in a solution, or in a sample. And so average here is really the key word. And so if a sample has a really, really high temperature, what that means is that the molecules in that sample have a high average motion. And so notice that these molecules in the sample have large arrows to represent the high average motion that they have. And so they're moving around a lot and very, very fast now. Low temperature on the other hand, of course, means that the samples the molecules in that sample have low average motion. And so notice that these molecules have small arrows to represent that they're moving very, very slowly in comparison to the high temperature samples. Now, temperature is not to be confused with thermal energy. So once again, temperature is the average kinetic energy. However, thermal energy is the total kinetic energy of molecules that's transferred specifically as heat. And so, if we take a look at our image down below over here on the right hand side, we could distinguish between temperature and thermal energy. And so notice that we're comparing two samples. Ah, hot coffee pot over here on the left hand side with, ah, large swimming pool over here on the right hand side. Now, of course, the hot coffee pot. If we measure its temperature, it's going to be quite high. It's gonna have a high temperature because the average kinetic energy, uh, in, um, these molecules is really, really high. They're moving really, really fast over here on average. And of course, the swimming pool over here is going to have low temperature. It's gonna be quite cool if you were to jump into that swimming pool, and that's because the molecules on average have low temperature. However, if we focus on the thermal energy, what we'll find is that the hot coffee pot because it has such a small volume, it actually has a lower thermal energy in comparison to the swimming pool over here, which has a much, much larger volume. And so the swimming pool over here is because it has so many more molecules. The total energy off all of these molecules adds up to B'more energy than the molecules over here in the hot coffee pot. And so that means that the swimming pool, simply because it has a much larger volume, has a higher thermal energy. Mawr. Total energy over here in the swimming pool because it has simply, ah, lot more molecules and the hot coffee pot, even though on average they have, ah, higher temperature MAWR motion TOTAL. There is a lot lower thermal energy in the hot coffee pot because it has such a small volume in comparison to this large swimming pool. And so this year concludes our introduction to kinetic energy temperature and thermal energy, and as we move forward in this lesson, we'll talk more specifically about waters thermal properties. So I'll see you all in our next video
Water’s High Specific Heat
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in this video, we're going to introduce waters high specific heat, and so waters. High specific heat really is what allows it to resist temperature changes. Now specific heat is really just defined as the amount of heat energy that's required to either raise or lower 1 g of water just one degree Celsius. And so because water has a high specific heat, it means that it takes a relatively high amount of heat in order to either raise or lower 1 g of water just one degree Celsius. And so think about it. If you've ever tried to make some pasta first you have to put water into a pot, and then you have to put that water in the pot onto a stove. But the water doesn't start boiling immediately. Once you put that water onto the hot stove, it takes some time. It takes quite a lot of energy in order to heat up that water and raise its temperature. And so this is water's ability to have a high specific heat and resist temperature changes, and it also works in the opposite way. In terms of lowering the temperature of water. It takes ah lot to lower the temperature of water. So if you have a water bottle, for instance, and you throw it into the freezer, it doesn't freeze immediately. It takes several hours in order to cool down water until it freezes. And so water has this incredible ability to resist temperature changes because it has such a high specific heat. Now, resisting temperature changes is really, really critical for life to maintain home eo Stasis because once again, the temperatures of the environment are constantly going to be changing. Some days it'll be hot. Other days it will be really cold. And so life needs to have this ability to maintain home yo Stasis, maintain an internal set of conditions. And because the cells are made up of a lot of water, uh, they are able to resist the temperature changes and maintain constant temperatures inside the self. Despite the fact that the outside of the cell is constantly changing and so down below, we're showing you an example of waters high specific heat. So notice we have this beaker here that's filled up with water, and we're applying some heat here. Ah, flame to the water to heat it up, but notice that the water here isn't really impressed by the amount of heat. And it's saying, Is that all you got? Bring on the heat. It's gonna take a lot more heat. Thio raise my temperature than just a little flame here. And so that is just this idea that water has a high, specific heat. It takes a lot of energy to raise or lower 1 g of water, one degree Celsius, and that is what allows water to resist temperature changes. And so this here concludes our introduction to Waters high specific heat, and we'll be able to get some practice applying these concepts moving forward in our course, so I'll see you all in our next video.
Which of the following is due to the high specific heat of water?
a) Oil does not mix with water.
b) A lake heats up more slowly than the surrounding environment.
c) The high surface tension of water.
d) Sugar dissolves in hot tea faster than in iced tea.
Oil does not mix with water.
A lake heats up more slowly than the surrounding environment.
The high surface tension of water.
Sugar dissolves in hot tea faster than in iced tea.
Water’s High Heat of Vaporization
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So, in addition to having a high specific heat, water also has a high heat of vaporization. Now vaporization is also referred to as evaporation. And so vaporization, or evaporation is really just referring to the phase transition when a substance goes from, ah, liquid state to a gaseous state, or essentially when a substance is going to be converted from its liquid state to a gas state. And so the heat of vaporization is specifically defined as the amount of heat energy that's required to convert g of liquid into its gaseous state. Now, once again, water has a really, really high heat of vaporization, which means that it takes a relatively large amount of energy in order to convert 1 g of liquid water into its gaseous state. And so the reason that water has such a high heat of vaporization is due to the abundance of hydrogen bonds that form between the water molecules and its liquid form. And so, if we take a look at our example, image down below of waters heat of vaporization notice that we're showing you the heat of vaporization of water and so notice that we have a pot here that's filled with boiling water, since we're applying a lot of heat energy to it, and so we zoom into this boiling water down below. Here, we can see that it's going to be in its liquid water form, which we know is going to be highly dense, compact, and it's going to be forming hydrogen bonds between different water molecules and so you can see the H bonds or the hydrogen bonds are forming when waters in its liquid state. Now, if we want to convert liquid water into the gaseous form water vapor, then we need to apply a high amount of energy and heat. And that's exactly what this flame is doing here. And so when we do that, we're capable of breaking all of the hydrogen bonds that form between the liquid water molecules. And when we break all of those hydrogen bonds, the water molecules are capable of escaping into the gashes, form the water vapor form and noticed that the water vapor is much less dense. Thes water molecules are much more spread apart, and there are no hydrogen bonds, no H bonds forming between the water molecules in the water vapor form, the gaseous form. And so when you could see that this image is just a zoom in into the steam here, that's above the water. And so the main point here is that water has a high heat of vaporization, meaning it takes a large amount of energy to convert 1 g of liquid water into gaseous state. And that also helps with maintaining home yo states Stasis and making sure that water stays in its liquid form, which is critical to maintain life. And so this year concludes our introduction to Waters high Heat of vaporization, and we'll be able to get some practice applying these concepts in our next video, so I'll see you all there.
Which if the following defines the term evaporation?
a) The conversion of a liquid into a vapor.
b) The conversion of a solid into a vapor.
c) The conversion of a vapor into a liquid.
d) The conversion of a vapor into a solid.
The conversion of a liquid into a vapor.
The conversion of a solid into a vapor.
The conversion of a vapor into a liquid.
The conversion of a vapor into a solid.
Choose the correct statement:Liquid water ________.
a) Is less dense than ice.
b) Has a lower specific heat than most other molecules.
c) Has a higher heat of vaporization than most other molecules.
d) Is nonpolar.
Is less dense than ice.
Has a lower specific heat than most other molecules.
Has a higher heat of vaporization than most other molecules.