Observation made when a sealed vessel containing dry ice is opened at room temperature

Dry ice is the name for carbon dioxide in its solid state. At room temperature, it will go from a solid to a gas directly. While carbon dioxide gas is invisible, the very cold gas causes water vapor in the air to condense into water droplets, thus creating fog.

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.

the answer is barium and copper bromide