Intermolecular Forces, States of Matter, and Evaporation/Condensation

1. Why do solid particles stay in place even though they vibrate?

Because solids do not have enough space for particles to move past each other.

2. How do liquid particles move?

Liquid particles can move past each other, which allows liquids to flow.

3. What happens during evaporation?

During evaporation, atoms or molecules at the surface of a liquid gain enough energy to break free from the liquid and become gas.

4. What determines the boiling point of a liquid?

The boiling point depends on the strength of the attractive forces between molecules. Stronger attractions (like in polar molecules) result in higher boiling points.

5. Why does water evaporate even at room temperature?

Because evaporation depends on the average energy of molecules. Some molecules have enough energy to escape the liquid even if the temperature is below the boiling point.

6. How does evaporation help the body cool down?

When we sweat, water evaporates from the skin. The molecules that escape take energy with them, lowering the average temperature of the remaining water and cooling the body.

7. What happens to water molecules during condensation?

Water molecules lose energy, slow down, and stick together, forming liquid droplets. This is how clouds form.

8. Why does temperature increase slowly during boiling in some cases?

Because the heat is used to break intermolecular forces rather than increase kinetic energy immediately. The liquid stays at boiling temperature until enough energy allows molecules to escape as gas.

8.5) what’s an intermolecular force?

the attraction between molecules.

9. How does air and wind affect evaporation?

Air movement removes evaporated molecules from the surface, increasing evaporation. More air flow allows evaporation to happen faster.

10. What is precipitation and how does it form?

Precipitation forms when water droplets in clouds clump together and become heavy enough to fall as rain, snow, or other forms of precipitation.

11. What is vapor pressure?

Vapor pressure is when molecules escape a liquid into the gas phase at a temperature below the boiling point. It depends on temperature and intermolecular forces.