Question

A small quantity of the inert gas argon (Ar) is added to incandescent light bulbs to reduce vaporization of tungsten (W) atoms from the solid filament. What volume of argon gas measured at 760 mmHg is needed to fill a 0.21-L light bulb at a pressure of 1.30 mmHg? Assume the argon gas temperature remains constant.

Answer 1

Since the substances involved here are gases we can use the ideal gas equation for this case. It is expressed as PV=nRT1. At a constant temperature and number of moles of the gas the product of PV is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows: P1V1 =P2V2 V2 = P1 x V1 / P2 V2 = 1.30 x 0.21 / 760 V2 =0.0004 L