Question

question 1 (multiple choice worth 4 points) (01.05r mc) rubbing alcohol evaporates from your arm quickly, leaving a cooling effect on your skin. how do the molecules of gas compare to the molecules as a liquid? the gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles. the gas particles move faster than the liquid particles, and the bonds of the molecules are broken during evaporation to allow gas atoms to spread apart. the gas particles move slower but have the same molecular structure and the same attraction between them as the liquid particles. the gas and liquid particles move at the same speed, but the bonds of the molecules are broken during evaporation to allow the gas atoms to spread apart.

Explanation:

To solve this, we analyze the properties of matter during phase change (evaporation from liquid to gas for alcohol):

1. Molecular Composition: Evaporation is a physical change, so the molecular composition of alcohol (ethanol) remains the same in gas and liquid phases.
2. Particle Motion: In gases, particles have higher kinetic energy (move faster) than in liquids, where intermolecular forces restrict motion more.
3. Intermolecular Attractions: Gas particles have weaker intermolecular attractions (since they are farther apart and move freely) compared to liquid particles (where attractions are stronger, keeping them closer).
4. Bond Breaking: Evaporation does not break covalent bonds within molecules (only intermolecular forces weaken), so options mentioning “bonds of the molecules are broken” are incorrect.

Let’s evaluate the options:

• First Option: Matches the analysis (same molecular composition, faster motion, weaker attractions).
• Second Option: Incorrect (gas particles move faster, not slower, than liquid particles).
• Third Option: Incorrect (evaporation does not break molecular bonds, only intermolecular forces).
• Fourth Option: Incorrect (gas and liquid particles do not move at the same speed, and bonds are not broken).

Answer:

The gas particles move faster, have the same molecular composition, and have weaker attractions between them than the liquid particles.