in this video, we're going to begin our lesson on the properties of water, specifically cohesion and adhesion. Now cohesion is specifically referring to the ability for water molecules to stick together essentially for water molecules to stick to other water molecules. Water sticking toe water now adhesion, on the other hand, is the ability for water molecules to stick to other molecules that are not water. So, for example, water sticking to glass. And so if we take a look at our image down below, over here on the left hand side, noticed that we're showing you an example of the cohesion and adhesion of water. And so we're specifically taking a look at a glass of water like this one over here, and we're zooming in to the bottom of the glass of water over here on the right hand side. And so notice that when the water molecules stick to other water molecules represented by these green lines that you see throughout right here, this represents cohesion once again cohesion, instability for water, molecules to stick together, water sticking tome or water. And this happens because of hydrogen bonding. Recall water molecules can hydrogen bond to other water molecules. And so, once again, waters, hydrogen bonding is gonna be very, very important for its properties. Now, when water molecules stick to other molecules that air not water, for example, water sticking to the glass. That is an example, of course, off adhesion when water molecules stick to other molecules that air not water, since glasses, not water, and so water will specifically adhere to objects that are either polar or charged and glasses certainly a polar object. Now the cohesive and adhesive abilities off water are due to its ability to hydrogen bond. And so water is capable of hydrogen bonding with the glass. And that's what allows it to adhere to the glass. And together. The cohesive and adhesive ability of water gives water a relatively high surface. Tension and surface tension is really just a measure of the difficulty in breaking the surface of liquid with force. And so notice down below. Over here, on the right hand side of our image, we're showing you a little example of the surface tension of water, and so notice that this paper clip right here has been laid down on the surface so gently in a way that it does not break the surface of the liquid water. And so this water is really acting like a surface for the paperclip. And so thes cohesive adhesive abilities that create high surface tension is really quite a unique property for liquid water. And most liquids do not display these cohesive and adhesive properties. And so this is something that we should be beneficial for because these properties are gonna be really, really critical, uh, in the ability for water to act as a solvent for life. And so this here concludes our introduction to the properties of water cohesion and adhesion and as we move forward in our course will continue to talk Mawr and Maura about the properties of water. So I'll see you all in our next video.
Properties of Water- Cohesion and Adhesion Example 1
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all right. So here we have an example problem that wants us to fill in the blank in this sentence, using one of these four potential answer options down below. In the example, problem says cohesion, surface tension and adhesion are properties of water molecules that blink an option A says increases with temperature. Now, in our last lesson video, we never mentioned that these properties cohesion, surface tension and adhesion will actually increase with temperature. And in fact, this is not going to be true, so we can eliminate Option A. For that reason, Option B says that it will increase with Ph. And once again we never mentioned this in our previous lesson videos, and this is simply not going to be true. So now we're between either option C or Option D an option C says are a result of non polar Covalin bonding. But of course, we know from our previous lesson videos that water molecules are held together, uh, using polar co violent bonds, not non polar Covalin bonds. And so the non polar here makes this part false. And so, of course, this Onley leaves Option D here as the correct answer. And so cohesion, surface tension and adhesion are all properties of water molecules that are a result of hydrogen bonding. And so Option D here is the correct answer to this practice problem. And really, it's the hydrogen bonding that water molecules are capable of forming that allow water to have cohesive and adhesive properties and to create a relatively high surface tension. And so this year concludes this example problem, and I'll see you all in our next video.
Which of the following effects can occur because of the high surface tension of water?
a) Lakes cannot freeze solid in winter even with extremely low temperatures.
b) A spider can walk across the surface of a small pond.
c) Organisms can resist temperature changes, although they give off heat due to chemical reactions.
d) Sweat can evaporate from the skin, helping to keep people from overheating.
Lakes cannot freeze solid in winter even with extremely low temperatures.
A spider can walk across the surface of a small pond.
Oganisms can resist temperature changes, although they give off heat due to chemical reactions.
Sweat can evaporate from the skin, helping to keep people from overheating.
Cohesive forces in liquid water occur when:
a) The H atoms on molecules of H2O hydrogen bond to O atoms on adjacent molecules of H2O.
b) The H atoms on molecules of H2O hydrogen bond to other H atoms on adjacent molecules of H2O.
c) The atoms on molecules of H2O hydrogen bond to other O atoms on adjacent molecules of H2O.
d) None of the above are correct.
The H atoms on molecules of H2O hydrogen bond to O atoms on adjacent molecules of H2O.
The H atoms on molecules of H2O hydrogen bond to other H atoms on adjacent molecules of H2O.
The atoms on molecules of H2O hydrogen bond to other O atoms on adjacent molecules of H2O.