Question

A scientist is working with a hazardous, colourless, and odourless gas, silicon tetrafluoride (SiF₄). It is contained in a poly(ethyl methacrylate) (PEMA) polymeric container at 2 atm pressure. Please answer the following questions given the information below.

Permeant: silicon tetrafluoride (SiF₄), 104.1 g/mol

Polymer: poly(ethyl methacrylate) (PEMA)

P_{M,298 K} = 1.1x10^–14 cm³ STP cm/cm² s Pa

Q_d = 45 kJ/mol

Surface area of container: 300 cm²

Volume of container: 5000 cm³

Volume of room: 60 m³

Temperature: 298 K

1. If the airborne exposure limit for SiF₄ is 3 ppm over an 8 h period, what is the minimum wall thickness of the container?
2. If the pressure of the container is reduced to 0.5 atm, what is the new minimum wall thickness?
3. If the volume of the room is reduced by half, what is the new minimum wall thickness?
4. If the volume of the container is reduced by half, what is the new minimum wall thickness?
5. If the temperature of the room is increased by 20 ∘C, what is the new minimum wall thickness (please consider all factors that are affected by temperature)?

Answer 1