50ml graduated cylinder is filled with 30 mL hexane at a 21°C laboratory. Pressure of air in the room is 1 atm. Hexane evaporates and diffuses through the air in the cylinder and hexane level drops to...

Extracted text: 50ml graduated cylinder is filled with 30 mL hexane at a 21°C laboratory. Pressure of air in the room is 1 atm. Hexane evaporates and diffuses through the air in the cylinder and hexane level drops to 28 ml after a while. Vapor pressure of hexane at 21°C is 0.198 atm. Density of hexane is 655 kg/m? (Hexane is diffusing through stagnant air.). a. Calculate the rate of evaporation at steady state in kg mol/s. m?. b. Calculate the required time for hexane level to drop from 30ml to 28mL. (Assume 50 ml is marked at the very top of the graduated cylinder and 50 mL level (length of the cylinder) is measured as 20cm) (Use table 6.2-1 for diffusivity data)


Extracted text: TABLE 6.2-1. Diffusion Coefficients of Gases at 101.32 kPa Pressure Diffusivity [(m²/s)10 or cm²/s] Тетрerature System °C K Ref. Air-NH3 273 0.198 (W1) Air-H,O 273 0.220 (N2) 25 298 0.260 (L1) 42 315 0.288 (M1) Air-CO2 3 276 0.142 (H1) 44 317 0.177 Air-H2 273 0.611 (N2) Air-C-H;ОН 25 298 0.135 (M1) 42 315 0.145 Air-CH,COOН 273 (N2) (C1) 0.106 Air-n-hexane 21 294 0.080 Air-benzene 25 298 0.0962 (L1)