True or false? During a phase change (from solid to liquid, for example) the temperature of the material stays the same.

The temperature changes. Think of taking a cup of ice out by the pool in on a hot summer day. The ice begins to melt. The sun was changing its previous temperature. If it stayed the same, the now puddle of water would remain ice.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.