A cylinder of argon gas contains 50.0 L of #Ar# at 18.4 atm and 127 °C. How many moles of argon are in the cylinder?

1 Answer
Feb 19, 2016

Answer:

The cylinder contains #"28.0 mol Ar"#.

Explanation:

Use the ideal gas law.

#PV=nRT#, where #n# is moles and #R# is the gas constant.

Known
#P="18.4 atm"#
#V="50.0 L"#
#T=127^@"C+273.15=400 K"#
#R="L atm K"^(-1) "mol"^(-1)#
https://en.m.wikipedia.org/wiki/Gas_constant

Unknown
#n#

Solution
Rearrange the equation to isolate #n#. Substitute the known values into the equation and solve for #n#.

#PV=nRT#

#n=(PV)/(RT)#

#n=(18.4cancel"atm" * 50.0cancel"L")/(0.082057338 cancel"L" * cancel"atm" * cancel"K"^(-1) * "mol"^(-1) * 400"K")="28.0 mol Ar"#