Name five properties of water that are vital to life.

Question

Accepted Answer

Hi, everyone. And welcome back. Our next question says which the following is not a characteristic of water that is essential to life. A water has high specific heat capacity. B water acts as a universal solvent. C water is a better respiratory medium due to high density or D water molecules exhibit cohesion and adhesion. Well, when we look at our answer, choices, one of these should probably stick out just in this terms of common sense, if we think about it and that would be choice. C water is a better respiratory medium due to high density. Well, the density of water is a characteristic of it and it is more dense than air. So it's about 8000 times more dense than air. But this does not make it a better respiratory medium. A more dense substance is going to be more viscous, move more slowly. So air is going to be a more suitable respiratory medium as it moves much more easily through the through lungs, through respiratory passages than water. The other reason air is better, it has a higher oxygen concentration. So it's less work for an organism to extract the oxygen from that air. But mainly we would say that it's, it's lower density of air, makes it a better respiratory medium. So that's why choice c is our answer to be thorough here. Let's look at our other answer choices to understand why they're not correct. So each of these should be a characteristic of water that's essential to life. A water having a high specific heat capacity. Let's recall that heat capacity is the amount of heat necessary to raise the temperature of a substance. And the fact that water has a relatively high specific heat capacity means that it can absorb a lot of heat energy before its temperature is changed. In addition, water can take away heat and energy when it evaporates. So if water gets heated up enough, it will evaporate and that will take away the heat energy from whatever uh substance or organism it was on. When we think about living things, we know that they need to exist within a very narrow temperature range. So having this substance as part of them that doesn't change temperature easily means that water helps moderate temperature fluctuations that might otherwise damage organisms. So you can see how that high specific heat capacity is a characteristic of water essential to life. So this is not our answer choice. B water acts as a universal solvent. Well, this one is a bit of a misnomer. Water is not a universal solvent. Water is a polar molecule and therefore it doesn't dissolve nonpolar mole molecules easily, but it is an excellent solvent of charged particles and polar molecules. And that's due to its polar nature and specifically its ability to do hydrogen bonding or h bonding as I wrote here. So we have that big difference in electronegativity between the hydrogen and the oxygen. Meaning that the water molecules have that partial negative charge in the region of the oxygen and a partial positive charge in the region of the hydrogens. So when we have, for instance, ions dissolved in water, the water mole tend to surround and form a shell around those particles around that charged particle. All their little oppositely charged regions lined up and of course, surrounding your ion with the water molecules is a great way of dissolving your ions spreading them out throughout the solvent. And similarly, with polar molecules, the same thing because so many uh nutrients essential to life are charged particles or polar molecules. It's very important to have a solvent that can be able to transport these things throughout living organisms. So choice B is another characteristic of water essential to life. And finally, choice D water molecules exhibit cohesion and adhesion. Remember that cohesion is the tendency of water molecules to stick together and adhesion, the tendency to stick to other things. And again, this is the result of their polar nature ability to hydrogen bond results in the surface tension of water. These tendencies to stick together and into other things. And here again, we come to that role as transporting nutrients through living things. So specifically, this means that water molecules form a little shell or a layer around cells around the surface of cells, which makes them very ideal for transporting nutrients into and out of cells. This can even for instance, in the case of plants allow nutrients to be transported against gravity. As the uh cohesive and adhesive properties of water molecules allows nutrients to be transported up a plant. So chisti yet another essential to life characteristic of water. So our only answer choice here that is not a characteristic of water essential to life is choice C water is a better respiratory medium due to high density. See you in the next video.

Name five properties of water that are vital to life.

Key Concepts

Cohesion and Adhesion

High Specific Heat Capacity

Solvent Properties

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