Select all the correct locations on the image. the heating curve shows temperature vs. energy gain. which parts of the curve represent a gain in potential energy?

The part of the graph which is marked by 2nd and 4th boxes are the regions where the substance gains potential energy.

Potential energy in the matter is stored in form of chemical energy in the chemical bonds. At this point, the temperature of the substance doesn't rise. But when the temperature rises, actually the kinetic energy of the substance rise, because of the molecular vibration.

In the graph, the line marks a distinct pattern where the temperature rises at certain places, and in certain places, it's still, even if the energy is supplied. So here in the parts of graph where it shows a horizontal curve, the potential energy of the matter rise.

solute : a solute is a substance that is dissolved in another substance is known as a solvent. it is mixed with a special mixture know as homogeneous mixture.

solvent: a solvent is a substance that dissolved a solute, which results in a solution is known as solvent.

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.