 ## GOB Chemistry

Learn the toughest concepts covered in your GOB - General, Organic, and Biological Chemistry class with step-by-step video tutorials and practice problems.

Gases, Liquids and Solids

# Chemistry Gas Laws

Chemistry Gas Laws are laws that relate together the pressure, volume and temperature of a gas.

Examining the Chemistry Gas Laws
1
concept

## Chemistry Gas Laws 58s
Play a video:
the chemistry gas laws are laws that relate together the pressure, volume and temperature of a gas. Now we're going to say here that they can be derived from the ideal gas law. Remember, your ideal gas law is PV equals NRT. And to remember your four chemistry gas laws. Just remember, be great at chemistry. The first chemistry Gas Law B is Boyle's law. Boyle's law looks at the relationship between volume and pressure. G stands for the gay loose axle on it relates together pressure and temperature. A A is for Apple cadres law, avocados Law looks at volume and moles. And then finally C. C stands for Charles Law, which relates together volume and temperature. Now that we have chemistry gas laws connected to these pairings, let's take a look at the Siris of videos where we go in greater depths with each one of these chemistry gas laws

The Ideal Gas Law can be used to determine each of the Chemistry Gas Laws

2
concept

## Chemistry Gas Laws 2m
Play a video:
Doyle's law states that volume and pressure are inversely proportional at constant moles and temperature. Now it's named after robert Boyle and it illustrates how the volume of a container is greatly affected by pressure changes. Now here, how do we depict this relationship? When we say they're inversely proportional, we can say that they're on different levels. So we're gonna say volume is inversely proportional to one over inversely proportional pressure. Which means that v the proportionality symbol one over P. This shows us an inverse relationship between volume and pressure. Think of it as volume being a numerator pressure, being a denominator there on different levels. So they are different from one another. If one goes up the other one has to go down. Now this is illustrated if we take a look at variables here, if we take a look, we have two containers with movable pistons. Volume is just the space within my container. So if we look at this image, we can say that the volume is pretty high pressure represents the downward force that we have on the piston. Now the downward force on the piston must be pretty low, which is why the piston hasn't slid down lower. Okay, and here we can see volume is high pressure is low. Now let's say that we garnered enough force from the pressure. We're able to push down on this piston. We can see that the volume now is smaller, so the volume now is low and that's a direct result of the pressure being hired. Now how do we depict this inverse relationship graphically Well here to show an inverse relationship between two variables, you would show it like this? So this graph that showed me that my volume is decreasing over time and as a result of pressure is increasing over time. This is how we depict an inverse relationship between two variables. Now, how do we show Boyle's law formula in in the in form of a digested formula. Here we say that it becomes P one V one equals P two, V two. This represents our adjusted formula. Also, our Boyle's Law formula Where P one is our initial volume. V one is our initial RP 1's our initial pressure. V one is our initial volume. P two is our final pressure and V two is our final volume. Now, remember we went over how we derived these different types of formulas under the ideal gas laws application section. If you don't know what that is or if you haven't seen those videos yet, I suggest you go back and take a look at how we can derive this formula. Now we just know that it's connected to Boyle's law and therefore called the Boyle's Law formula. Okay, so keep this in mind. Boyle's law says that pressure and volume are inversely proportional, meaning if one is high the other one would be low

Boyle's Law: Volume and Pressure are inversely proportional at constant n and Temperature.

3
concept

## Chemistry Gas Laws 2m
Play a video:
now gay loose tax law, also known as amazon's Law says that pressure and temperature are directly proportional at constant moles and and volume. The Now as temperature increases our gas particles collide with the walls more rapidly, That's because they're absorbing the thermal energy and they're using it to propel themselves faster inside the container. And this will cause an increase in my pressure. Now remember pressure itself equals force over area. We said that the volume is constant, so your area would be constant, It's staying the same. If I'm increasing my temperature again, my gas will move faster inside the container. They're gonna hit the walls more rapidly, but also with more force. So my forces increasing my area is staying the same. This causes my pressure to increase. Okay, so that's why pressure and temperature are directly proportional. Now, we're going to say, remember that with all gas law calculations, we must use the S. I. Units for temperature in kelvin. So our units for temperature here are in kelvin. Now, what is the pressure temperature relationship there, directly proportional? So you just say that P is directly proportional to t and that happens when moles and volume are the same or fixed? Not the same, but fixed. How do we show this? Well, here we have two images of pistons, containers with pistons that are movable in the first image, I haven't applied a heat source. So we're going to say that our temperature here would be low, the temperature is low. So our molecules don't have extra outside energy to absorb. So they're not moving as vigorously as rapidly, They're not hitting the container with as much force and therefore a pressure would be low. But all of a sudden I had a flame. The container absorbs the heat, which eventually transitions to the molecules absorbing this heat, allowing them to move more rapidly and with greater force. So temperature is high, which eventually it's a greater force which leads to greater pressure. So pressure would be high. How would I depict this in a plot? They're both directly proportional. So we'd say that they both would be increasing together. So you'd have a line that's increasing over time. What would their adjusted Formula B or the gay loose sacks? Formula it would just be P one over T. One equals P two over T. Two. Again, take a look at my ideal gas law applications section on how we could derive this formula. Now we know that it's connected to the gay loose sacks or amazon's law. Now, remember with these variables, we'd say initial pressure is P one. Initial temperature is T one. Final pressure will be P. Two and final temperature would be T. Two. So remember when we're talking about gay loose tax law or amazon's law, that pressure and temperature are directly proportional when our moles and on our volume V. R. Constant or fixed

Gay-Lussac's Law: Pressure and Temperature are directly proportional at constant n and Volume.

4
concept

## Chemistry Gas Laws 1m
Play a video:
oh God! Rose Law states that are volume V and our moles and are directly proportional at constant pressure, P and temperature T. Now it's named after Amadeo of um and it shows that the volumes of gasses are connected to their number of molecules here. We're going to say that the relationship between volume and moles is that V is directly proportional to moles. And again that happens when P and T are constant or fixed. The way we depict this with our mobile pistons is if we take a look here at this image, we're gonna say, this container has a lot of dots, so it has a lot of mold or number of molecules. So moles would be high to house all of these molecules. We'd want our volume to be high because gas is like it when there's an opt amount of distance between them. But what happens if I take some of these molecules of gasses out, what are moles of gas would be below and I no longer need as much space for them. So my volume would be low. They both are high together or low together when pressure and temperature are constant or fixed. Now, how do we depict this in a plot? Since they're directly proportional, you'd say this line of V. N. N. Which showed increasing over time, Where you could start out at 0l and it increases over time as our moles increase. Now, what would our adjusted formula or our avocados law formula B. That would just be the one over N one Equals V two over and two. So our initial variables here. Initial modes would be N one initial volume. V one. Final M.nolds will be in two. Final volume would be V two. So just remember our volume and moles are directly proportional, meaning they're both high together or low together when our pressure and temperature are constant or fixed.

Avogadro's Law: Volume and n are directly proportional at constant Pressure and Temperature.

5
concept

## Chemistry Gas Laws 2m
Play a video:
trials law states that volume and temperature are directly proportional and constant moles and and pressure peak. It's named after Jackie's Charles and it illustrates how the volume of a container is greatly affected by volume here to show this direct proportionality between volume and temperature, we just say V is directly proportional to T when our moles and and pressure pier constant or fixed. If we were to illustrate this with movable pistons, if we take a look here, we'd say that in this first image, our volume is low and we haven't applied any temperature or heat to this container. I mean so the temperature would be low here. I'm applying a flame to this. This is going to cause higher temperature. And what's happening here is because the piston is movable and the pressure is constant. Our gas particles are gaining enough outside energy to basically hit all corners of this container including the movable piston up and that's what caused the volume to also expand. So our volume is high. How would we illustrate this direct proportionality between volume and temperature? What we say here that they're both increasing or decreasing together. So you can illustrate this by a line that's going up over time as they both increase the adjusted formula or Charles law formula would just become V one over T one equals V two over T two. Here we'd say that our initial volume is V one, Our initial temperatures, T one Final volume is V two and our final temperature is T two. So remember when it comes to Charles long, we say that volume and temperature are directly proportional, which means they both can increase or decrease together if our moles and and our pressure P are held constant or fixed.

Charle's Law: Volume and Temperature are directly proportional at constant n and Pressure.

6
example

## Chemistry Gas Laws Example 1 1m
Play a video:
7
Problem

A 10.0 L cylinder with a movable piston exerts 3.00 atm of pressure. What will happen to the pressure if the volume of the container increases to 20.0 L?

a) It will double

b) It will decrease by half

c) It will increase slightly

d) No change

8
Problem

A sealed container with a movable piston contains a gas with a pressure of 1380 torr, a volume of 820 mL and a temperature of 31°C. What would the volume be if the new pressure is now 2.83 atm, while the temperature decreased to 25°C? 