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Structure of Atoms .txt
So what holds the nucleus or the protons and neutrons together?
Structure of Atoms .txt
Well, the force that holds the nucleus together is called a nuclear force.
Structure of Atoms .txt
This is just one type of electrostatic force and it's a very strong force.
Structure of Atoms .txt
Now, once again, it's very important to understand the fact that due to the small size of our electrons orbiting our nucleus, the atom is composed mainly of empty space.
Dalton鈥檚 Law on Partial Pressure .txt
Well, let's recall what the kinetic molecular theory tells us about the behavior of ideal gases.
Dalton鈥檚 Law on Partial Pressure .txt
Well, it tells us two important things.
Dalton鈥檚 Law on Partial Pressure .txt
First, gas molecules have no volume.
Dalton鈥檚 Law on Partial Pressure .txt
And second, gas molecules exert no force on one another.
Dalton鈥檚 Law on Partial Pressure .txt
That means if we had a system continuing containing two gas molecules, gas molecule A and gas molecule B, that means these two guys have no volume and they exert no force on one another, so they can't communicate.
Dalton鈥檚 Law on Partial Pressure .txt
So in many different ways, molecule A is invisible to molecule B and molecule B is invisible to molecule A.
Dalton鈥檚 Law on Partial Pressure .txt
And that leads directly into the following results pressure created by one gas molecule is independent of the pressure created by another gas molecule.
Dalton鈥檚 Law on Partial Pressure .txt
In other words, the pressure that this gas molecule exerts on the walls of my system of my container is independent of what this guy exerts on my wall of the container.
Dalton鈥檚 Law on Partial Pressure .txt
So to find the total pressure, my system of two gas molecules, I simply have to add up this pressure and this pressure.
Dalton鈥檚 Law on Partial Pressure .txt
And that's exactly what B states.
Dalton鈥檚 Law on Partial Pressure .txt
The total pressure of any system of gas molecules is equal to the pressure exerted by each an individual gas molecule.
Dalton鈥檚 Law on Partial Pressure .txt
So p one plus p two plus all the way up to PM, assuming that my system is composed of M gas molecules.
Dalton鈥檚 Law on Partial Pressure .txt
So this is simply a mathematical way of representing any series.
Dalton鈥檚 Law on Partial Pressure .txt
So let's look at this system.
Dalton鈥檚 Law on Partial Pressure .txt
So suppose we have a closed system of five gas molecules, two blue and three red.
Dalton鈥檚 Law on Partial Pressure .txt
Now, we have two types of molecules and a total of five molecules.
Dalton鈥檚 Law on Partial Pressure .txt
So my one type is blue.
Dalton鈥檚 Law on Partial Pressure .txt
My second type is red.
Dalton鈥檚 Law on Partial Pressure .txt
To find the total pressure of my system here, I would simply add up all the individual pressures.
Dalton鈥檚 Law on Partial Pressure .txt
So five molecules altogether.
Dalton鈥檚 Law on Partial Pressure .txt
So I add up to five molecules p blue one plus p blue two plus p red one plus p red two plus p red three.
Dalton鈥檚 Law on Partial Pressure .txt
Now, I could also say that my p total is equal to the pressure due to blue gas molecules.
Dalton鈥檚 Law on Partial Pressure .txt
This guy plus this guy plus the pressure due to red gas molecule or p one plus p two plus p three.
Dalton鈥檚 Law on Partial Pressure .txt
Another way of saying this is the pressure due to my blue gas molecule is the partial pressure of my blue molecule and this guy is the partial pressure of my red molecule.
Dalton鈥檚 Law on Partial Pressure .txt
So partial pressure refers to the pressure exerted by one type of gas molecule.
Dalton鈥檚 Law on Partial Pressure .txt
In this case, a blue gas molecule or a red gas molecule in a mixture of gases.
Dalton鈥檚 Law on Partial Pressure .txt
In this case, two types of gas molecules, red and blue.
Dalton鈥檚 Law on Partial Pressure .txt
So another way of representing this formula or equation is the following.
Dalton鈥檚 Law on Partial Pressure .txt
So we can represent the partial pressure of any gas in a mixture of gasses by the following equation.
Dalton鈥檚 Law on Partial Pressure .txt
The partial pressure is equal to the mole fraction of that gas in our mixture times the total pressure.
Dalton鈥檚 Law on Partial Pressure .txt
In other words, I want to represent this in this following way let's see what we do.
Dalton鈥檚 Law on Partial Pressure .txt
P total is equal to well, how many blue molecules on the system?
Dalton鈥檚 Law on Partial Pressure .txt
Two.
Dalton鈥檚 Law on Partial Pressure .txt
How many molecules altogether?
Dalton鈥檚 Law on Partial Pressure .txt
Five.
Dalton鈥檚 Law on Partial Pressure .txt
So the mole fraction of my blue guy is two over five times my P total plus the partial pressure of my red molecules.
Dalton鈥檚 Law on Partial Pressure .txt
We have three red molecules over five red molecules times the P total.
Dalton鈥檚 Law on Partial Pressure .txt
So this is the partial pressure due to the blue molecules.
Dalton鈥檚 Law on Partial Pressure .txt
These guys are the same plus the partial pressures into the red molecules.
Dalton鈥檚 Law on Partial Pressure .txt
These guys are also the same.
Dalton鈥檚 Law on Partial Pressure .txt
Gives us P total.
Dalton鈥檚 Law on Partial Pressure .txt
And look, common denominator adds a two and three.
Dalton鈥檚 Law on Partial Pressure .txt
I get five and five.
Dalton鈥檚 Law on Partial Pressure .txt
The five cancel and I simply get P total equals P total.
Dalton鈥檚 Law on Partial Pressure .txt
So this formula makes sense.
Dalton鈥檚 Law on Partial Pressure .txt
And in fact, this formula is called a Dalton's Law of partial pressures.
Dalton鈥檚 Law on Partial Pressure .txt
And this law can be derived using the ideal gas law.
Dalton鈥檚 Law on Partial Pressure .txt
And let's see how.
Dalton鈥檚 Law on Partial Pressure .txt
Well, suppose in part E, we have three types of gas molecules and each type has N number of moles.
Dalton鈥檚 Law on Partial Pressure .txt
So n one, N two and n three.
Dalton鈥檚 Law on Partial Pressure .txt
So red molecules, blue molecules and purple molecules.
Dalton鈥檚 Law on Partial Pressure .txt
Well, what's the total number of molecules or moles in molecules of my system?
Dalton鈥檚 Law on Partial Pressure .txt
Well, in this case, it was two plus three.
Dalton鈥檚 Law on Partial Pressure .txt
So we added them.
Dalton鈥檚 Law on Partial Pressure .txt
So we do the same thing.
Dalton鈥檚 Law on Partial Pressure .txt
We add the moles, add the number of molecules.
Dalton鈥檚 Law on Partial Pressure .txt
The N total is n plus n one plus n two plus n three is my total.
Dalton鈥檚 Law on Partial Pressure .txt
So, if I want to find the total pressure using the ideal gas law, the following has to be done.
Dalton鈥檚 Law on Partial Pressure .txt
I rearrange it a bit and bring the D over on this side.
Dalton鈥檚 Law on Partial Pressure .txt
And again, P total is equal to while my volume is constant, I'm assuming it's constant.
Dalton鈥檚 Law on Partial Pressure .txt
My temperature is constant.
Dalton鈥檚 Law on Partial Pressure .txt
Also, R is a gas constant.
Dalton鈥檚 Law on Partial Pressure .txt
It's always constant.
Dalton鈥檚 Law on Partial Pressure .txt
And now I plug in N total or the total number of molecules in my system.
Dalton鈥檚 Law on Partial Pressure .txt
Now I can go to the next step.
Dalton鈥檚 Law on Partial Pressure .txt
And instead of writing N total, I plug in all these three guides or the addition of these three guides and I get in parentheses n one plus n two plus n three times RT divided by V. And now I need simple algebra to distribute to each guide.
Dalton鈥檚 Law on Partial Pressure .txt
And I get n one R T over V plus n two r T over V plus n three r T over V. And we see using the ideal gas law that we get the same exact thing as up here.
Dalton鈥檚 Law on Partial Pressure .txt
So P total is equal to partial pressure of gas one plus partial pressure of gas two and plus partial pressure of gas three.
Dalton鈥檚 Law on Partial Pressure .txt
So once again, we found this formula first using the kinetic theory.
Dalton鈥檚 Law on Partial Pressure .txt
And then we confirm that in fact, this works using the ideal gas law.
Dalton鈥檚 Law on Partial Pressure .txt
So this formula may makes a lot of sense.
Oxidation Numbers Example .txt
In this example, we're going to assign oxidation numbers to atoms of molecules.
Oxidation Numbers Example .txt
Here we have nine molecules.
Oxidation Numbers Example .txt
So let's begin.
Oxidation Numbers Example .txt
In this molecule, we have an N atom at an fatom.
Oxidation Numbers Example .txt
An fatom, according to our table, precedes or is more important than an N atom.
Oxidation Numbers Example .txt
And that means we first assign our number.
Oxidation Numbers Example .txt
Oxidation number to F gets negative one.
Oxidation Numbers Example .txt
But since we have three F's, that means this one has a negative three.
Oxidation Numbers Example .txt
And since our entire molecule is neutral, this one must be plus three.
Oxidation Numbers Example .txt
Plus three minus three gives you neutral.
Oxidation Numbers Example .txt
So zero charge makes sense.
Oxidation Numbers Example .txt
Let's look at Ammonium NH Four.
Oxidation Numbers Example .txt
NH four has an overall charge of plus one.
Oxidation Numbers Example .txt
Now let's look at the atoms.
Oxidation Numbers Example .txt
Our H atom is more important than N atom, so we assign to H first.
Oxidation Numbers Example .txt
Since H is not attached to a metal atom, we assign H a plus one.
Oxidation Numbers Example .txt
So four h is get plus four.
Oxidation Numbers Example .txt
Since we want a plus one overall charge, this guy must be a minus three.
Oxidation Numbers Example .txt
Minus three plus four gives you a plus one.
Oxidation Numbers Example .txt
Let's look at no three.
Oxidation Numbers Example .txt
This guy has negative three as an overall charge.
Oxidation Numbers Example .txt
So let's look at the individual atoms.
Oxidation Numbers Example .txt
All is more important than N. That means we first assign our oval, so all gets a negative two.
Oxidation Numbers Example .txt
Since we have a three zeros, this becomes negative six for three OS.
Oxidation Numbers Example .txt
And since we want a negative one overall, our N must be plus five.