Question

Question: What type of forces, intramolecular or intermolecular:

1. Prevent ice cubes from adopting the shape of their container?
2. Are overcome when ice melts?
3. Are overcome when liquid water is vaporized?
4. Are overcome when gaseous water is converted to hydrogen gas and oxygen gas?

Short answer

1. Intermolecular forces
2. Intermolecular forces are overcome
3. Yes, the intermolecular forces are overcome when liquid water is vaporized.
4. Intramolecular forces are overcome when gaseous water is converted to hydrogen gas and oxygen gas.

Step-by-step solution

Intermolecular forces

Intermolecular forces are the forces that exist between different molecules. More the intermolecular interactions, more will be the tendency of the molecules in preventing any change in the shape as this will weaken their interactions.

For ice

In the case of ice (solid water), the intermolecular interactions are more, thus preventing the ice from adopting the shape of the container.

Intermolecular interactions in phases

Intermolecular interactions in the case of solids are comparatively more than the liquids.

Heat Conversion

When the solid (here in this case it is ice) melts, the heat supplied in this process is used to weaken these interactions. Thus, during the melting of the ice, these intermolecular interactions are overcome or precisely decrease.

Intermolecular forces

For liquid water, the intermolecular interactions are comparatively higher than in its vapor form.

Vaporization

During vaporization, these interactions in liquid water weaken by the heat energy provided by the external source. Thus, intermolecular interactions are overcome when liquid water is vaporized.

Intramolecular forces

Intramolecular forces are the forces that act within the molecules. In the case of water, these intramolecular interactions are H-bonding.

During conversion to hydrogen gas

When gaseous water gets converted to hydrogen and oxygen gas, the H-bonding interactions present in gaseous water are overcome.

Hydrogen or oxygen gas doesn’t contain any such H-bonding. Thus, the heat supplied is used to overcome these H-bonding interactions.