Question

Two chemical compounds, P and Q , are mixed together in a baker . state which observations or measurements will show that a chemical change has taken place

Answer 1

In addition to new products, the following may accompany a chemical change:

1. Heat, light or any other radiation may be given off or absorbed.

2. Sound may be produced.

3. A change in smell may take place or a new smell may be given off.

4. A colour change may take place.

5. A gas may be formed.

Some examples for above statements

1. Burning of any substance is always accompanied by the production of heat and light.

2. Explosion of fireworks produce heat, light and sound. During this the unpleasant gases will produce and pollute the atmosphere. (It is not advisable, so it is avoided).

3. The stale food gives bad odour (smell)

4. The cut fruits and vegetables change its colour after some time.