Steam is sometimes used to melt ice. is this change physical or chemical?

Steam is the gaseous phase of water. It is used in some cases to melt ice. Melting of ice is the conversion of solid water to liquid water. This is just a phase change in which water changes its state from solid state to liquid state. But the chemical composition of water remains unchanged. Water has the same molecular formula in both the solid (ice) and liquid states. Hence, the conversion of solid ice to liquid water by steam refers to a physical change.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.