00:01
To determine the vapor pressure of the solution, mass of urea is given, 82 .4 grams and volume of water is given.
00:12
212ml, density of water is given, 0 .994 grams per ml.
00:21
Then molar mass of water we know.
00:24
So first we can calculate the mass of water.
00:27
Mass of water is equal to density of water into volume of water so we will get 210 .7 to 8 grams then we can calculate number of moles of urea equal to given mass divided by its molecular mass so we'll get 1 .372 moles also number of moles of water will be equal to given mass by molecular mass which is equal to 11 .707 moles.
01:25
Next we can calculate the number of mold fractions of urea for that total moles will be equal to 1 .372 moles that is moles of urea plus moles of water we will get 13 .079 therefore mole fraction of water equal to moles of water divided by total moles of urea 13 .079 so we will get mole fraction will be equal to 0 .8951 also vapor pressure the solution will be called to vapor pressure of solution equal to 0 .8951 into 42 .18 mhm hg will be equal to 37 .75 m mhg and let's calculate the relative lowering of vapor pressure so relative lowering of vapor pressure.
02:47
So relative lowering of vapor pressure equal to equal to p0 minus p s by p0 will be equal to 42 .18 minus 37 .75 divided by 42 .18.
03:07
So we will get 0 .105...