Answer:
APPEARANCE
A pure substance has properties that are constant throughout the whole sample. This means that a pure substance will have a constant appearance, colour, density, melting point and boiling point throughout the sample. ... This horizontal flat line part of the graph is typical of a pure substance
MELTING POINT
melting point, temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. As heat is applied to a solid, its temperature will increase until the melting point is reached. More heat then will convert the solid into a liquid with no temperature change
BOILING POINT
The boiling point of a pure substance is the temperature at which the substance transitions from a liquid to the gaseous phase. At this point, the vapor pressure of the liquid is equal to the applied pressure on the liquid. The boiling point at a pressure of 1 atmosphere is called the normal boiling point.
