Is matter around us pure?

Classify the following as chemical
or physical changes:
• cutting of trees,
• melting of butter in a pan,
• rusting of almirah,
• boiling of water to form steam,
• passing of electric current,
through water and the water
breaking down into hydrogen
and oxygen gases,
• dissolving common salt in
water,
• making a fruit salad with raw
fruits, and

• burning of paper and wood.