A differential flow mixing calorimeter has been used to measure the excess molar enthalpy H-m(E), of (nitrogen + dimethyl ketone)(g) at standard atmospheric pressure over the temperature range 333.2 K to 423.2 K. The measurements are analysed using the corresponding states correlation of Tsonopoulos using his parameter n as a disposable parameter. The measurements are found to be consistent with measurements of the second virial coefficient B, the isothermal Joule-Thomson coefficient phi = B - T(dB/dT) and the pressure derivative chi = - T-2(d(2)B/dT(2)) of the heat capacity of dimethyl ketone. As the H-m(E) measurements are of good accuracy (nitrogen + dimethyl ketone)(g) is recommended as a test system for checking the correct operation of gas phase mixing calorimeters.