Question

5. When a candle burns, both physical and chemical changes take place.
Identify these changes. Give another example of a familiar process in
which both the chemical and physical changes take place.​

Answer 1

Answer:

When a candle burns, both physical & chemical changes occur.

• On heating, candle wax melts and form liquid wax. It is a physical change. Since it again turns into solid wax on cooling. This is a reversible change.
• When a candle is burnt in air, the mass of the product is increased due to atmospheric oxygen which show a that it is a chemical change.

Cooking of food, boiling of eggs are examples of both physical and chemical changes.

Answer 2

Answer:

Solid wax change into liquid ----> Gaseous (fuel) [physical state)

gaseous wax --->burn and produce light and heat (chemical channge)

another example is petrol as fuel, wood burning for food, etc