00:01
Let's make this chemistry problem about pressures and when the stock clocks are opened and all of that.
00:07
But before i work on this problem, i recommend students to pause the video, do the questions themselves, and come back to see if they 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, the...
00:43
Stopcocks on the bureaus are open right and we should look at the information that we have so we have the volume after which is three so let's start with n2 nitrogen the useful information or the useful formula in this case would be this right, p1, 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.
02:08
We already have v1 actually.
02:12
We have v1.
02:13
We have v1.
02:14
Since the question stated that there are 3 1 liter flasks so v1 in this case would be 1 liter and you are left with p 2 which we want to find out times v2 since we know that the volume after the stopp are open there is 3 liters and we can obviously rearrange to make p to the subject so it would be 1 divided by 3 right which is the 1 times 1 and divide by 3 so p 2 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.
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 equal em and divide that by 760 being the unit conversion here, right? and this would give us the pressure of water as 0.
04:16
And we are given the mass of water, right? which is 2 grams.
04:27
So think of the formula that would be the most suitable in the situation.
04:34
Yep, it is n equals pv divided by n r t.
04:40
So this formula here, right? and we know the pressure.
04:53
We want to figure out the mole, right? so we know the pressure and we can times that by three acres, since that is a volume off that the stockoff is open.
05:14
And we know r is like a constant, which is 0 .082.
05:25
This is the unit for the constant, and we know the temperature they have given it to us.
05:33
And i use my calculator and i got 0 .106, five, six, six, six.
05:39
Of water.
05:43
And now that we have the moles, we can figure out the mass of water, right? so the formula for that is mass equals mole...