Calculate the work done on the system in Joules when 2.0 moles of ${\mathrm{N}}_2$ reacts with 6.0 moles ${\mathrm{H}}_2$, to form ${\mathrm{NH}}_3$against a pressure of 1.0 atm at 27° C. 

${\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)⟶2{\mathrm{NH}}_3\left(\mathrm{g}\right)$

(Given : R = 8 J/mol K)