Question

Nitrogen is diffusing through a polymer. The nitrogen concentration on the high pressure side of the polymer is 3 kg/ms, and on the low pressure is 1 kg/m 3 Part A If the nitrogen concentration on the low pressure side is decreased to 0.5 kg/m3, how will the diffusion flux change? decrease. increase O stay the same. could either increase or decrease.

Answer 1

1. (B)

$Flux=J=-D\frac{\mathrm{d} C}{\mathrm{d} x}$

Decreasing the concentration on the lower side will cause dC to increase which will result in increase in diffusion flux.

2.

$5.47\times10^{-8}=-D_{ox}(\frac{c_{l}-c_{h}}{0.004})$

Just put the values and get the required answer. You haven't given the data on diffusivity coefficient of oxygen in PVC sheet.