Physical change is a change where no any chemical reaction takes place only the chemical composition of matter changes. It is a reversible process .
Burning of newspaper, rusting of iron, plant changes carbon dioxide and water into sugar (photosynthesis) are chemical reaction and irreversible process.
The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .
