Question

which best describes why absolute zero is the lowest possible temperature? at absolute zero, the motion of the molecules of a substance almost stops. because when you add heat, ice melts into water. because of the kinetic energy of molecular motion. because heat is related to temperature.

Explanation:

To determine why absolute zero is the lowest possible temperature, we analyze each option:

• Option 1: At absolute zero (0 K or -273.15 °C), molecular motion (kinetic energy) theoretically ceases (or is at its minimum possible state), which aligns with the definition of absolute zero.
• Option 2: Describes a phase change (ice to water) which is about melting point, not absolute zero.
• Option 3: While kinetic energy of molecular motion is related, the first option directly explains the state at absolute zero.
• Option 4: States a general relation between heat and temperature, not why absolute zero is the lowest.

So the best description is the first option.

Answer:

A. At absolute zero, the motion of the molecules of a substance almost stops.