Answer:

1. Physical changes may or may not be reversible changes. Like, turning of water into ice is an example of reversible changes but growth in height is an irreversible change. Chemical changes are changes that occur in the chemical properties of the substance like its flammability, radioactivity, etc.

2. The cake can't be “unbaked” and “unmixed” to change it back to the raw eggs, flour, and other ingredients. So making a cake is irreversible. Combustion reactions are generally irreversible.

3. Some examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc. Chemical changes are irreversible i.e. original substance cannot be recovered.

4. The glass tumbler or its broken pieces are made of glass and there are no new molecules created, so its is a physical change. However, you cannot get back the glass from the broken pieces so, the change is irreversible.

5. When the balloon is kept in the sun, due to Sun's heat, the kinetic energy of gaseous particles inside the balloons also gets increased and the balloon expands. This will increase the pressure on the walls of the balloon. It continues to expand and comes to a stage when the baloon bursts.

Explanation:

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