How do you calculate the molar enthalpy of condensation (#DeltaH_(cond)#) for ammonia when 100.0 g of #NH_3# gas turn into a liquid at its boiling point?

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68,500 J of energy are released in the process.

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Answer 1 · 2017-06-19T17:19:15

By calculating the quotient, #"energy released"/"moles of ammonia"#......and get #DeltaH_"condensation"=-11.7*kJ*mol^-1#

We interrogate the process...........

#NH_3(g) rarr NH_3(l)+Delta_"condensation"#

We want #DeltaH_"condensation"# with units of #kJ*mol^-1#.

We have parameters for a #100*g# mass of ammonia.....

And thus, #(-68500*J)/((100.0*g)/(17.03*g*mol^-1))=-11665.6*J*mol^-1#, i.e. #-11.7*kJ*mol^-1#.