I had a question : Heat energy was supplied to melt ice at -15 degree Celsius. But it was not enough to turn the ice completely into water at 0 degrees. From my calculation I obtained that a mixture of 60% water and 40% ice was produced as a result of heating. Finally it said to describe the internal energy of that mixture. I couldn't managed to do that part. So I was wandering what was the answer to it. Also what determines its internal energy ?