Water has a latent heat of vaporization of 2257 kJ/kg. Steam is used to heat a copper tube of 0.358 kg from 21 degrees C to 100 degrees C. All the heating is due to the heat released from the steam condensing. What is the minimum mass of steam that could have been used? Give your answer in Standard SI units. (Use cCu = 0.386 kJ/kg . K)