Final answer:
To determine which sample, a solid or a liquid, has more energy, we must ask which has the most molecular motion, as this indicates higher kinetic energy and temperature. In solids, particles vibrate about fixed positions; in liquids, they slide past each other but maintain close contact, indicating more energy. The sample with the most molecular motion typically has more energy and a higher temperature.
Step-by-step explanation:
To determine which sample has more energy between a solid and a liquid, the most relevant question to consider is C. Which sample has the most molecular motion? Molecular motion is more indicative of a sample's energy content, as increased motion corresponds to a higher average kinetic energy of the molecules, which translates into a higher temperature for the material. In a solid, atoms or molecules are closely packed and vibrate about fixed positions, whereas in a liquid, the particles have enough energy to move past each other, though they are still in contact, leading to a indefinite shape but a definite volume.
When comparing two blocks of the same solid material, the one with molecules shaking more vigorously on their hypothetical 'springs' (vibrational motion) has more kinetic energy and is therefore at a higher temperature. According to the conservation of momentum, when two such blocks come into contact, energy will transfer from the block with more molecular motion (higher kinetic energy) to the one with less motion, until thermal equilibrium is reached. The block with higher molecular motion is analogous to a warmer liquid relative to a cooler solid.
The entropy of a substance also plays a role in determining its state and behavior. Entropy, which is related to the number of microstates or ways particles can be arranged, generally increases with more molecular motion. For instance, gases, where particles move freely and rapidly, have higher entropy compared to solids, where particles are restricted to vibrational movements.