What mass in grams of steam at 100°C should be mixed with 298 g of ice at its melting point, in a thermally insulated container, to generate liquid water at 15.0°C? The specific heat of water is around 4186 J/kg•K. The latent heat of fusion is around 333 kJ/kg, and the latent heat of vaporization is around 2256 kJ/kg.