00:01
Let's make this chemistry problem about pressures and when the stopcocks are opened and all of that.
00:07
But before i work on this problem, i recommend students to pause the video, do the question themselves, and come back to see if they've got it right or not.
00:14
That is a true way of knowing if you fully understand the topic.
00:19
So hopefully pause the video and another question.
00:21
Now let's work on it together.
00:23
So in this situation, we want to calculate the vapor pressure stopcocks.
00:44
On the bureaus are open, right? and we should look at the information that we have.
01:00
So we have the volume after, which is three, so let's start with n2 metrogen.
01:33
The useful information, or the useful formula in this case, would be this right.
01:38
P1, v1, because p2, v2 because we have the pressure on the volume.
01:45
So we have, and we want to figure out p2, right? because it's the after pressure, we already have the initial pressure.
01:56
So i work on this.
01:58
We have 1 atm times v1 equals, we already have v1 actually.
02:13
We have v1 since the question stated that there are 3 1 liter flasks.
02:18
So v1 in this case would be 1 liter and we are left with p2 which we want to find out times v2 since we know that the volume after the stoppocket open there's 3 liters and we can obviously rearrange to meet p to the subject.
02:35
So it would be 1 divided by 3 right? which is the 1 times 1 and divide that by 3.
02:41
So p2 should be for nitrogen.
02:46
Now that we've worked on nitrogen, i think it would be, we can move on to water.
02:55
So for water, we were given the pressure, which was 42, and obviously this unit here is very useless to us.
03:16
We would want to convert it into atm right.
03:19
So what is the conversion for that? it is 1 atm is equal to 7.
03:35
So if you want to figure out the pressure of h2o in atmospheric pressure, we need to do 1 atm and divide that by 760 being the unit conversion here.
04:10
Right as you can see and this would give us the pressure of water as 0 .0 5 3 5 to pressure and we are given the mass of water right which is 2 grams so think of the formula that would best that would be the most suitable in the situation yep it is n equals pv divided by m r t so this formula here right and equals here and we know the pressure we want to figure out the mole right so we know the pressure and we can times that by three a little bit of this since that is a volume after the stock is open and we know r is like a constant which is 0 .082 this is the unit for the constant for the constant and we know the temperature they have given it to us...