4. The vapor from a sample ofan unknown compound occupies volume of 910.5 mL at a temperature of 313.6 K and pressure of 6176 tOrT: The vapor has mass Of 22.462 g W...

At $60^{\circ} \mathrm{C}$ , compound $\mathrm{X}$ has a vapor pressure of 96 $\mathrm{mm} \mathrm{Hg}$ benzene $\left(\mathrm{C}_{6} \mathrm{H}_{6}\right)$ has a vapor pressure of $395 \mathrm{mm} \mathrm{Hg},$ and a $50 : 50$ mixture by mass of benzene and $\mathrm{X}$ has a vapor pressure of 299 $\mathrm{mm}$ Hg. What is the molar mass of $\mathrm{X} ?$

In this problem. We want to find the molecular mass of this compound. So we have the density and grants for leader and since molecular masses grants from all, we have to find the number of bulls In the sample using p vehicles NRT. So take the temperature and add 273 In order to get the temperature in Calvin. Then we're going to convert the pressure in mm of Mercury two atmospheres, One atmosphere is equal to 760 of Mercury. So use that as a conversion factor to get the pressure and atmospheres Let the Volume Equal one leader. So we're going to plug in our values. So we have the pressure one leader and which we're solving for our leaders at the atmosphere divided by militants Calvin and the temperature in Calvin. So the reason why we let the volume equals one leader is because we have the grams in one leader from the density. So that's why we want the volume to be one leader because we want the moles in one leader. So then we're just going to solve for end and we solve this, we do .08-06 times 363 divided by .9908. And we get in as many moles. So now this is the mass of one leader or the moles in one leader and we have the mass of one leader. So therefore we're just going to divide the mass of one leader by the moles and one leader. So we're able to get the molar mass in grams per mole

In this problem, we want to find the molecular formula of the sulfur vapor, one atmosphere of pressure, 973 K. And 9730.8012 grants for leader for the density of sulfur. So we want to know the molecular formula and sulfur just is just the element sulfur. Um there's just going to be a subscript on it when it's a vapor. So first of all, let's use p vehicles energy to find the moles of the sulfur. So we're just going to plug in everything that were given for our we're going to use 0.8 to 06 leaders times atmosphere by my mole. I am Skay. So now there are units match, we are going to get the Bowles of the sulfur and then molecular weight is grams per mole. So we are told that we have .8012g in one leader. And recall that we use one leader as the volume in the previous step. So we can go ahead and just use that mass for that many moles. Because this this is the mold and the mass in one leader of the sulfur. So we're just going to do the mass divided by the moles. And then we get the Michael. Wait, so that's the molecular way of our compound. So we know that this compound is comprised only of sulfur. So because this surprise only of sulfur, we can divide by the atomic mass of sulfur. So we're going to take our molecular weight and divide by the atomic mass of the sulfur. And then we end up getting two or approximately two. So that means we have to sulfur atoms in the Formula, so therefore it's just s. two. So die sulfur.

So here we are determining the molecular formula of the sulfur vapor. So fastly the molar mass. And the number of moles of the compound needs to be calculated but fast. We're dealing with the ideal gas equation. So it recalled that his P. V. Is equal to end uh tea. Or we're solving for the moles. The moles is equal to P. V. Divided by R. T. Plug in our values to get not point not 1 to 5 moles. And so the molar mass is equal to the mass divided by the moles. We plug in our values. So we have not 0.8012 g divided by the moles, not point not 1 to 5 moles. We got the molar mass 64.9 g per mole. So finally we can look at the ratio that is equal to the actual molar mass of sulfa divided by the simplest formula molecular mass of sulfa. You have 64.9 g per mole, divided by 32.7 g per mole. We get approximately two, so therefore the molecular mass of sofa can be obtained by multiplying the ratio obtained with the empirical formula to have S. Multiplied by two. This gives us S. Two, so the molecular formula of the sulfur vapor is S. Two.

Yeah, Hi there. In this problem, we are to calculate the molar mass, given the variables that we need to do this. So all we need is an equation from our unit. There's an equation that tells us smaller mass is going to be equal to mass times. The universal cop gas Constant times t divided by pressure. Time is volume. Let's go ahead and plug these values from the problem into this equation and calculator. Mueller, Mass. First of all, our mass, we are given 7.60 g of the compound. When I look at the pressure, I am given a pressure in tour. So for my universal gas constant, I want to select the universal gas constant that has tor in it, which is the 62.4 leaders Times tour over mold times. Calvin and the temperature were given 183 degrees Celsius in the problem. We know that the temperature has to be in Kelvin. So if I take 1 83 and add to 73 to that, I get 456 Calvin in the denominator. I need my pressure in my volume in the problem We're told that the pressure is 179 tour and the volume is 3.87 Leaders looking at our units tour will cancel, Kelvin will cancel and leaders will cancel. This leaves us the units grams per mole, which are the units of Mueller Mass. So it looks like all we have left to do here is to calculate an answer. Calculating this gives me a Moeller mass of 312 grams per mole for this compound. And that would be our answer. Thank you so much for watching. I hope that you have a wonderful day.