At these conditions, the binary molecular diffusion coefficient of CO2 in air is 0.161 cm2 /s, but the effective diffusion coefficient of CO2 within the porous medium is only 0.011 cm2 /s. Fresh air containing no CO2 blows over the surface of the slab so that the convective mass transfer coefficient for CO2 (kc) is 0.0037 cm/s. Use the appropriate concentration-time chart to determine at what depth from the surface in the porous material the CO2 will be 3.0 mole% after a period of 30 minutes.

There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. in the first step, calcium carbide and water react to form acetylene and calcium hydroxide: cac2 (s) + 2h2o (g) → c2h2 (g) + caoh2 (s) =δh−414.kj in the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6c2h2 (g) + 3co2 (g) + 4h2o (g) → 5ch2chco2h (g) =δh132.kj calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. round your answer to the nearest kj .