00:02
Hi there.
00:03
In this question, we are trying to determine the molecular weight or the molar mass of this substance.
00:11
So molar mass means grams per mole.
00:16
Or in other words, the mass of the substance in grams divided by the number of moles of the substance that you have.
00:24
Well, for this substance, we are given a mass of 6 .155 grams.
00:35
However, we don't have mole right now.
00:39
So we need to figure out the number of moles so that we can get molar mass.
00:43
Well, we're given a pressure and a volume and a temperature, and this is a gas, so that means we can use the ideal gas law.
00:53
The ideal gas law is pv equals nrt, where p is pressure, v is volume, n is that number of moles we're looking for.
01:02
R is the universal gas constant, and t is the kelm.
01:05
In temperature.
01:06
Well, i want to rearrange this equation to solve for n.
01:10
So i'll divide both sides by rt.
01:12
That gives us n is equal to pv over rt.
01:21
Okay, so the number of moles is equal to pv over rt.
01:25
So let's go ahead and calculate that.
01:29
The pressure we are given is in tor.
01:32
We're told at 747 .2.
01:41
The temperature we are given, i'm sorry, we need volume next.
01:45
The volume we're given rather is 1 ,484 milliliters.
01:51
Well, we need this in liters because our r, our constant, is in liters.
01:56
So if we divide 1 ,484 by 1 ,000, because there are 1 ,000 milliliters in a liter, we get 1 .484 liters...