1.A system consists of liquid oxygen in equilibrium with oxygen vapor. How many phases are present? The system undergoes a process during which some of the liquid is vaporized. Can the system be viewed as being a pure substance during the process? Explain.
2.What is the settling velocity of a .5 micrometer silica sphere at 20 degrees Celsius and an ambient pressure of 150 kPa? The density of silica is 2600 kg/cubic meter.
3.How many particles would be present in a cubic meter of aerosol at the concentration of the U.S. PM-10 standard or 50 micrograms/cubic meter if the particles are .1 micrometer in diameter.
4.An old occupational hygiene rule of thumb is that a 10 micrometer (micron) silica particle settles at a rare of 1 ft/min (0.5 cm/s). What is the true settling velocity for such a particle? The density of silica is 2600 kg/cubic meter (2.6 g/cubic centimeter).