Question

Disu p uesuay U1 Apr 2020 Question 8 Not yet answered Marked out of 2.00 P Flag question Chemical (A) is being developed as a treatment for cancer. Chemical (A) is being released from the surface of a solid tablet into a liquid blood (B) stream. At the surface of the solid tablet, the molar fraction of (A) is, X, = 0.95. Pure liquid blood (B) flows at a distance of, d = 0.3 mm from the surface of the solid tablet. It is known that (B) is stagnant therefore the flux of B, N, = 0. The total concentration is, c = 57 mol/m and the diffusion of coefficient of (A) into (B) is, DAB = 3.6x10 m is. -10 2 Calculate the total flux of A, N, (diffusion and bulk motion)

Answer 1

Data provided in problem statement

Distance between diffusing surfaces (z) = 0.3 mm = 0.3 * 10-3 m

Total Concentration ( C ) = 57 mol / m3

Mole fraction of A in tablet = 0.95

Concentration of drug A on tablet ( CA1) = 0.95 *  57 mol / m3 = 54.15  mol / m3

Diffusuvity of A into blood (B) = 3.6 * 10-10 m2 /s

Now , Flux for A in non diffusing B can be given as ,

NA = DAB CCAI CA2) Hore As CA2=0. doug concentration in blood is zero. NA = 9.6 xi/10 mm 0.3 x 103 m (54.15-0) mole NA = Tmes. It 6.4988 10-3 mol/m²s.

Diffusion of drug into blood = 6.498 * 10 -5 mol / m2. s