Butane's (C4H10) molar enthalpy of vaporization is 22.44 kJ/mol and its normal boiling point is -0.4 degrees C. A 250-mL sealed Erlenymeyer flask contains 0.55g of butane at -22 degrees C. Assume the liquid does not decrease the available volume of the flask for the vapor. How much butane is present as a liquid under these conditions?