Which of the following represents a physical change to matter? a. combustion of carbon to form carbon dioxide b. rusting c. melting a stick of butter d. separating hydrogen gas from water,

Physical changes affect the form of matter, volume or state, without altering its composition or nature. During fusion, a material that is in the solid state becomes liquid when the temperature increases. It is called the melting point at the temperature at which this change of state is generated. This example of melting a butter bar is the passage of a solid material into a liquid state. Not all the materials have the same melting point because each one has its own melting point.