Answer
a. chemical change;
b. physical change;
c. chemical change;
d. chemical change
Work Step by Step
Natural gases contain methane. When methane is burned, it loses its identity during the combustion; therefore, this is a chemical change.
Evaporation is a type of phase transition. There is no loss of identity of what substance it is; therefore, this is a physical change.
Burning of liquid propane and oxygen from the air will produce carbon dioxide and water. You lose the identity of propane during the combustion process; therefore, this is a chemical change.
When the bicycle's material (such as iron) reacts with oxygen and moisture (such as water), you get a rusting reaction. This changes the identity of the bicycle's material (changes the identity of iron); therefore, this is a chemical change.
