1. The problem statement, all variables and given/known data What mass of steam initally at 150 degrees celcius is needed to warm 200g of water in a 100g glass container from 20 degrees celsius to 45 degrees celsius? 2. Relevant equations I think Q=mc(delta)T 3. The attempt at a solution using the above equation calculating the energy required to transfer the steam to 100 degrees and then the energy required to convert it to water and then the energy required to raise the water 25 degrees. That is not right though!