The graph shown below is the hypothetical heating curve showing the temperature of 1 mol of a substance versus the amount of heat energy added to said substance. a) Which line segment(s) correspond to the \textbf{solid}solid phase of the substance? b) Which line segment(s) correspond to phase changes? c) At what temperature does the substance \textbf{melt}melt ? 50.0 d) Using the figure, approximate the molar heat capacity of the substance in the liquid phase in \text{kJ mol}^{-1}\,^\circ\text{C}^{-1}kJ mol −1 ∘ C −1 . Express your answer to 2 decimal places.