Question

A container holds 1.1 g of argon at a pressure of 8.0 atm . you may want to review (pages 382 - 383) . how much will the temperature increase if this amount of heat energy is transferred to the gas at constant pressure? express your answer using two significant figures.

Answer 1

When heat energy at a constant pressure = the change of enthalpy

ΔH = Q

and when the internal energy of an ideal gas formula is:

ΔH = n.Cp.ΔT

and when Cp = (5/2) R   at a constant pressure of a monatomic ideal gas

∴Q = n.(5/2).R.ΔT

∴ ΔT = Q / [n.(5/2).R]

when Q is the heat required = 43.08 J (given)

and n is no.of moles = mass / molar mass

                                  = 1.1 g / 39.948 g/mol

                                  =  0.0275 moles

and R is gas constant = 8.314472J/mol K

by substitution:

ΔT = 43.08 J / (0.0275moles *(5/2) * 8.314472 J/mol K

      = 76.76  K