What is the approximate temperature of a 0.50 mol sample of gas at 750 mm Hg and a volume of 12 L?

1 Answer
Jun 6, 2016

T~=290*KT290K

Explanation:

We use the Ideal Gas Equation:

T=(PV)/(nR)T=PVnR

T=((750*mm*Hg)/(760*mm*Hg*atm^-1)xx12*L)/(0.50*molxx0.0821*L*atm*K^-1*mol^-1)T=750mmHg760mmHgatm1×12L0.50mol×0.0821LatmK1mol1

The key to understanding these problems is correct interpretation of the pressure reading. It is a fact that 11 atmatm will support a column of mercury 760*mm760mm high. So even though we report the "length"length of the column, this actually relates to the "pressure"pressure, and I used the conversion,

P=(750*mm*Hg)/(760*mm*Hg*atm^-1)P=750mmHg760mmHgatm1 ~= 1*atm1atm.

Pressure measurement by means of a mercury column was very common back in the day. These days, laboratories tend to want want to get rid of mercury columns because it is an absolute horror to clean up mercury spills. As a student, I found mercury absolutely fascinating, so I contributed to the problem.