Properties of Water- Thermal - Online Tutor, Practice Problems & Exam Prep

Water's thermal properties are crucial for life, characterized by high specific heat and high heat of vaporization. Specific heat refers to the energy needed to change the temperature of 1 gram of water by 1°C, allowing water to resist temperature fluctuations. Heat of vaporization is the energy required to convert liquid water to gas, influenced by hydrogen bonds. These properties help maintain homeostasis, ensuring stable internal conditions despite external temperature changes, vital for cellular function and overall biological processes.

Properties of Water- Thermal

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 this 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 can distinguish between temperature and thermal energy. And so notice that we're comparing 2 samples, a hot coffee pot over here on the left-hand side with a 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 in 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 of all of these molecules adds up to be 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. More total energy over here in the swimming pool because it has simply a lot more molecules. And the hot coffee pot, even though on average they have a higher temperature, more motion, total there's 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 here concludes our introduction to kinetic energy, temperature, and thermal energy and as we move forward in this lesson we'll talk more specifically about water's thermal property. So I'll see you all in our next video.

Water’s High Specific Heat

In this video, we're going to introduce water's high specific heat. And so, water's 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 one gram of water by 1 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 gram of water by just 1 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. It also works in the opposite way in terms of lowering the temperature of water. It takes a 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 critical for life to maintain homeostasis. Because once again, the temperatures of the environment are constantly going to be changing; some days it'll be hot, other days it'll be really cold. And so, life needs to have this ability to maintain homeostasis, to maintain an internal set of conditions.

And because the cells are made up of a lot of water, they are able to resist the temperature changes and maintain constant temperatures inside the cell despite the fact that the outside of the cell is constantly changing. And so, down below we're showing you an example of water's high specific heat. So, notice we have this beaker here that's filled up with water and we're applying some heat here, a 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 to 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 gram of water by 1 degree Celsius, and that is what allows water to resist temperature changes. And so, this here concludes our introduction to water's 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.

Water’s High Heat of Vaporization

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 a liquid state to a gaseous state, or essentially when a substance is going to be converted from its liquid state to a gaseous state. And so the heat of vaporization is specifically defined as the amount of heat energy that's required to convert 1 gram of liquid into its gaseous state. Now, once again, water has a really high heat of vaporization, which means that it takes a relatively large amount of energy in order to convert 1 gram 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 in its liquid form.

And so, if we take a look at our example image down below of water's 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, when 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 hydrogen bonds forming when water's 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 gaseous form, the water vapor form. And notice that the water vapor is much less dense. These water molecules are much more spread apart. And there are no hydrogen bonds, no hydrogen bonds forming between the water molecules in the water vapor form, the gaseous form. And so, when you can 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 one gram of liquid water into the gaseous state and that also helps with maintaining homeostasis and making sure that water stays in its liquid form which is critical to maintain life. And so this here concludes our introduction to water's 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 of 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.

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.

Here’s what students ask on this topic:

What is the difference between temperature and thermal energy?

Temperature is the measure of the average kinetic energy of molecules in a sample, indicating how fast the molecules are moving on average. Thermal energy, on the other hand, is the total kinetic energy of all the molecules in a sample, transferred as heat. For example, a hot coffee pot has a high temperature because its molecules move quickly on average, but it has lower thermal energy compared to a large swimming pool, which has more molecules overall, even if they move more slowly on average.

Why does water have a high specific heat?

Water has a high specific heat because of the hydrogen bonds between its molecules. These bonds require a significant amount of energy to break, meaning it takes more heat to raise the temperature of water. This property allows water to resist temperature changes, which is crucial for maintaining stable conditions in living organisms, helping them to maintain homeostasis despite external temperature fluctuations.

How does water's high heat of vaporization contribute to homeostasis?

Water's high heat of vaporization means it requires a large amount of energy to convert from liquid to gas. This property helps regulate temperature in living organisms. For example, when humans sweat, the body uses heat energy to evaporate the sweat, cooling the body down. This process helps maintain a stable internal temperature, which is essential for proper cellular function and overall biological processes.

What is the significance of water's thermal properties for life?

Water's thermal properties, such as high specific heat and high heat of vaporization, are crucial for life. High specific heat allows water to resist temperature changes, helping organisms maintain stable internal conditions. High heat of vaporization enables efficient cooling mechanisms, like sweating in humans. These properties ensure that cellular environments remain stable, supporting essential biological processes and overall homeostasis.

How does water's high specific heat affect climate and weather patterns?

Water's high specific heat affects climate and weather patterns by moderating temperatures. Large bodies of water, like oceans and lakes, absorb and store large amounts of heat without significant temperature changes. This heat is slowly released, influencing coastal climates to be milder compared to inland areas. This property also helps stabilize global temperatures, reducing extreme weather fluctuations and contributing to a more balanced climate system.