When it comes to Henry's law, it's important to understand that the solubility of a dissolved gas is directly proportional to the partial pressure of that gas over the liquid. So when we talk about Henry's law, we have to take into account two different relationships. Those are the pressure solubility relationship and the temperature solubility relationship. Now you're going to say, as the pressure increases above gases that are over the liquid, then the solubility of a gas increases. So all you have to think about is I have this closed container, and I can apply outward pressure on it, pushing down on this piston. That puts pressure on the gases that are above the liquid. And what happens here is that added pressure forces the gases to go down into the water, making them become dissolved, and thereby increase their solubility. Now we're going to say here changes in pressure have no effect on solids or liquids. So this is only in terms of increasing the solubility of gases if we increase the pressure on them. Now with temperature and solubility, that relationship we're going to say as the temperature increases, then the solubility of a gas decreases. So think about it like this. You have a pot of water that you're boiling on the stove. Right? The lid is closed. And if you give it enough time, what starts to happen? Steam starts to come out of the water. Well, that's gas escaping the water. It's no longer dissolved in the solvent, and therefore, its solubility is decreasing. Because remember, solubility is being able to dissolve a solute within a solvent. Now we're going to say here, temperature and solubility does not only affect gases, but it can also affect solids. We're going to say as the temperature increases, the solubility of a solid actually increases. So if you think you have like a hard substance like a rock or something in there, and you boil it in there, what's going to happen? Eventually, the rock is going to break apart, break down. It's going to become dissolved within the solvent. So just remember, increasing the temperature on solids increases their solubility.
Intro to Henry's Law - Online Tutor, Practice Problems & Exam Prep
Henry's Law examines how the pressure above a solution can directly affect the solubility of gases.
Henry's Law
Intro to Henry's Law Concept 1
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Intro to Henry's Law Example 1
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In general, as the temperature increases, the solubility of a gas in a given liquid decreases. Remember, when we increase the temperature of a solution, the gases are going to start escaping from that solution and thereby decrease their solubility. Conversely, the solubility of most solids in a given liquid will increase. So think about a hard substance like a rock; throw it into boiling water. Over time, that rock can be broken down by those increased temperatures. So here, we're going to have decreases and then increases. Therefore, option B would be the correct answer.
Which of the following is true for the solubility of NaCl (s) and CH4 (g) in water?