Calculate the mass in grams of urea that must be added to 150.g water to give a
ID: 691577 • Letter: C
Question
Calculate the mass in grams of urea that must be added to 150.g water to give a solution whose vapor pressure is 2.5mm Hg lessthan that of pure water at 40oC (vp H2O at 40oC=55.34mm Hg) Show each step, clear explanation to recieve life saverpoints, Thanks for the help Calculate the mass in grams of urea that must be added to 150.g water to give a solution whose vapor pressure is 2.5mm Hg lessthan that of pure water at 40oC (vp H2O at 40oC=55.34mm Hg) Show each step, clear explanation to recieve life saverpoints, Thanks for the helpExplanation / Answer
According Raoult's law relative Lowering of vapourpressure ( po-p) / po = mole fraction of the solute ( po - p ) / po =n / ( n+ N ) where po - p = lowering of vappour pressure = 2.5 mm Hg po = vapour pressure of pure water = 55.34 mm Hg n = No . of moles of urea = mass / Molar mass = m / 60 g / mol N = No . of moles of water = mass / Molar mass = 150 g / 18 g/mol = 8.334 moles n+N = ( m/ 60 ) + 8.334 Plug the values we get ( 2.5 / 55.34 ) = ( m/60 )/ [ ( m/ 60 ) + 8.334 ] 0.045 = (m/60 ) / [ m +( 60*8.334 ) / ( 60 )] 0.045 = m / ( m + 500.04) 0.045 * ( m + 500.04 ) = m 0.045 m + 22.50 = m m-0.045 m = 22.5 0.955 m = 22.5 m = 22.5 / 0.955 =23.562 g On solving we get mass of urea added m = 23.562 g Edit : calculation error.Related Questions
Hire Me For All Your Tutoring Needs
Integrity-first tutoring: clear explanations, guidance, and feedback.
Drop an Email at
drjack9650@gmail.com
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.