1. In class (lecture 17), we determined the rate that moles of He would be lost through a spherical Pyrex container when given that the partial pressure of He in the container (pH = 4 bar), inner diameter (200 mm) outer diameter (210 mm) of the container, diffusivity of He in Pyrex (4 x 10-14m/s), and solubility of He in Pyrex (S=4.5 x 104 kmol/m*bar) are all known. We also found that this container could be reasonably approximated as a plane wall with only 0.3% error. What is the ratio of wall thickness to outer radius of the Pyrex container that would allow us to approximate the container as a wall with less than 2% error? Provide a mathematical expression and provide a brief explanation (2-5 sentences) to support your