Answer
a) chemical
b) physical
c) chemical
d) chemical
e) chemical
Work Step by Step
a) This is a chemical change as it involves a colour change.
b) This is a physical change as there is no change in colour, heat is not released, no bubbles are released and no precipitate is formed.
c) This is a chemical change as heat is released.
d) This is a chemical reaction as heat is released.