Question

which of the following statements is not correct? a calorie is the amount of heat needed to raise 1 gram of water by 1 degree c it takes more heat to melt one gram of ice than it does to boil one gram of water to water vapor melting of ice requires enough heat energy to break the hydrogen bonds holding water molecules in a crystal lattice a change of state occurs when liquid water changes to ice or water vapor

Explanation:

1. Analyze Option A: The definition of a calorie is the heat required to raise 1 gram of water by 1°C, so this is correct.
2. Analyze Option B: The heat of fusion (melting ice) is about 80 cal/g, and the heat of vaporization (boiling water to vapor) is about 540 cal/g. So it takes more heat to boil water to vapor than to melt ice, making this statement incorrect.
3. Analyze Option C: Melting ice breaks hydrogen bonds in the crystal lattice, which requires heat, so this is correct.
4. Analyze Option D: Changing liquid water to ice (freezing) or water vapor (evaporation/boiling) are state changes, so this is correct.

Answer:

B. It takes more heat to melt one gram of ice than it does to boil one gram of water to water vapor