Question

Which of the following statements is correct?

Answer 1

When a substance condenses, heat energy is given off.

Option C.

Explanation:

When a liquid changes into gas or a solid changes into a liquid, the heat is needed to be supplied from the surrounding. So heat is absorbed in this process, not emitted.

Vapour pressure of a liquid is higher when the tendency of the liquid to boil is higher at a particular temperature. So vapour pressure of a liquid increases with increase in temperature until it boils. So a fluid with low boiling point will have higher vapour pressure st normal temperature, because it's near to its boiling point. So we get so much smell of alcohol when it's kept open.

Death valley is below sea level. So the height of atmosphere over death valley is more than normal places. So atmospheric pressure over death valley is more. So boiling of water or any liquid will take place at higher temperature than its boiling point.

Condensation happens when a substance is cooled. So heat is absorbed by the surrounding.