The amount of heat released when 12.0g of helium gas condense at 2.17 K is; -250 J
The latent heat of vapourization of a substance is the amount of heat required to effect a change of state of the substance from liquid to gaseous state.
However, since we are required to determine heat released when the helium gas condenses.
The heat of condensation per gram is; -21 J/g.
Therefore, for 12grams, the heat of condensation released is; 12 × -21 = -252 J.
