What is the pressure in millimeters of mercury of 0.0130 mol of helium gas with a volume of 208 mL at a temperature of 30 C?

1 Answer
anor277
Dec 5, 2016

We use the ideal gas equation to give an approximate pressure of #130*mm*Hg#

Explanation:

From the Ideal Gas equation #P=(nRT)/V#

#=(0.0130*cancel(mol)xx0.0821*cancelL*atm*cancel(K^-1*mol^-1)xx303*cancel(K))/(208*cancel(mL)xx10^-3cancelL*cancel(mL^-1))#

#=# #0.17*atm#

Now we were asked to quote the pressure in #mm*Hg#. It is a fact that #1# #"atmosphere"# will support a column of mercury #760*mm# high. This property is a handy laboratory measurement because you can measure small pressure differences by the difference in heights of mercury columns, relative to the daily atmospheric pressure.

#"Pressure "mm*Hg-=0.17*atmxx760*mm*Hg*atm^-1=??mm*Hg.#

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