Science MCQs

Plastics are large molecules called polymers made from monomers.

Monomers are derived from petroleum (crude oil).

Plastics can be easily moulded into various shapes when heated.

Plastics do not decay easily and cause long-term pollution.

A reversible change can be reversed to get the original material back.

Melting chocolate can be solidified again a reversible physical change.

Baking bread produces new substances that cannot revert to original ingredients.

Burning paper produces ash and gases that cannot be reversed.

Chewing involves physical breakdown and chemical action by saliva.

The reaction produces carbon dioxide gas water and sodium acetate.