According to the principle of calorimetry, Hgain=Hloss x×Lv×(x×C)×ΔT=mCΔT+mwCΔT Here, the latent heat of vaporization is Lv, the mass of steam condensed is x and the water equivalent of calorimeter is mw Substitute the value in above expression. x×540×(x×1)×(100−90)=1kg×1(90−9)+0.1kg×1(90−9) 550x=89.1 x=0.162kg x=162g