Question

DATA TABLE Trial 1 Trial 2 Mass of Erlenmeyer flask, rubber band and foil cover (g) 90.560 90.10 Temperature of water bath (°C) 100t 99.1 Mass of Erlenmeyer flask, rubber band, foil cover and condensed 0819 gas sample (9) Mass of the condensed gas sample (9) 251.59 Barometric (atmospheric) pressure (mmHg) 128.96 28.93 Volume of the Erlenmeyer flask (mL) 170 170 Molar mass of the unknown sample (g/mole) Average molar mass (g/mol): DATA ANALYSIS (Show your calculations) 1. Determine the mass of the condensed portion of the unknown that you placed in the Erlenmeyer flask. 2. Use the equation 4, along with the recorded temperature of the boiling water bath and the barometric (atmospheric) pressure of the room, to calculate the molar mass of your unknown compound. The molar mass of the unknown sample can be calculated using the ideal gas law: PV = nRT (Equation 1) P = pressure (mmHg) V = volume (mL) n = number of moles B-62.400 ML xmm Hg ideal gas constant The number of moles, n, is the mass, in g, divided by the molar mass (M). molxK m(9) M(g/mol) (Equation 2) 228.96)(170.)

Answer 1

Trial - 1 The mass of rubber band = 90.569 the and erlenmeyer blask, boil cover (9) 0.25 gm. Codensed gas sample mass = u m= 0.25 gm Temperature = 100°c Mz 375 373 K volume of the flask = 170 me. = 0'170 L. The Condensed gas sample follows the ideal gas law. I suppose, the molar mass = M gm /mol.

n = no. of mol= m gm 0.25 gm. M P = pressure = 28.96 mm Hg n = 0.0381 atm. R= universal gas constant = 0.082 L-atm.kimor PV=nRT 0.0381 atmx 0.1704 = 0.25 gm . x 0:082 &- afm to moi 43734 M= 0.0824 0.25x 373. -go/mol 0.17% 0.0381 = '118015 gm. moet M = 1180.5 qmsomol (Trial 1). Trial-2 T= 99.1°C= (273+99.1)k - 372.1 k. P= pressure = 28.93 mm Hg = 0.0380 atm. mass of the condensed gas sample = 0.59 gm .

v= volume of the blask, as the vapour sample so, occupy the total volume of blask. : v=0.170 L Asmo M=. molar mass = M gm/mol in= 0.59 am PV = nRT 00380 atmx 0.170 y = 0.59 gm x 0:082 X-alm. Kt - mol X 372.1 K . M= 2786.71 gm / moi avarage unknown molar mass of the - 12786.71+ 1180.51 compound =( 2 = 1983.60 gon/mol.