Question

which statement best describes why absolute zero is the lowest possible temperature?
a. it is the temperature at which all substances become solids.

b. it is the temperature at which particles have minimum possible energy and motion cannot decrease further.

c. it is the point where molecules lose all mass and disappear.

d. it is the coldest temperature found naturally in outer space.

Explanation:

To determine the best statement about absolute zero:

• Option A: Substances don't all become solids at absolute zero (e.g., helium remains liquid), so A is incorrect.
• Option B: Absolute zero is the temperature where particles have minimum possible energy (thermal energy) and molecular motion (kinetic energy) cannot decrease further (theoretically, particles have minimal vibrational motion). This matches the definition.
• Option C: Molecules do not lose mass or disappear at absolute zero; mass is conserved, and particles still exist (just with minimal motion), so C is incorrect.
• Option D: Absolute zero (0 K or -273.15 °C) is a theoretical limit and not naturally found in outer space (space has residual heat), so D is incorrect.

Answer:

B. It is the temperature at which particles have minimum possible energy and motion cannot decrease further.