Question

Select all the signs of a CHEMICAL change from the list below. (You may need to select more than one for full points)

Answer 1

Answer : The correct options are, Bubbles (gas formation)  and color change.

Explanation :

Chemical change : It is a change where changes occurs in the chemical composition and thus resulting in the formation of new compound or substance. It is an irreversible reaction.

The indication of chemical changes are :

Formation of gas bubbles.

Formation of precipitate.

Change in color.

Change in temperature.

Change in volume.

Change in smell or taste.

Evolution of heat, light and sound.

Physical change : It is a change in which shape and size of a substance changes. In this there is no change in the chemical composition of the substance and no new substance is forming. It is a reversible reaction.

The indication of chemical changes are :

Change in shape.

Change in form.

Change in size.

Change in phase.

(1) Evaporating : It is a physical change because only changes takes place in the phase from liquid phase to vapor phase.

(2) Bubbles (gas formation) : It is an indicator of chemical change.

(3) Color change : It is an indicator of physical change.

(4) Dissolving : It is a physical change because only changes takes place in the phase from solid phase to liquid phase.

Hence, the correct options are, Bubbles (gas formation)  and color change.

Answer 2

The answers are B, C, and D.