When two substances are mixed together, a color change is observed. does this mean that a chemical reaction has definitely occurred?
yes because any change indicates a chemical reaction.
no because some physical changes produce color changes.
no because color changes are not indicators of chemical reactions.
yes because color changes occur only when new compounds are formed.

Yes because color changes occur only when new compounds are formed.

Explanation: Chemical change is a change when the rearrangement of atoms take place and formation of new substances take place.

Physical change is a change when there is no rearrangement of atoms and there is only change in shape and size and no new substances are formed.

Chemical change is accompanied by following changes:

1. Absorption or release of energy

2. Change in color

3. Evolution of gas

4. Formation of precipitates

b) 10 minutes

girls stopped for 10 minutes.

a displacement distance is size of displ