At which temperature does the motion of atoms and molecules theoretically stop?

• A. 0 °C
• B. 0 K
• C. -273 °C
• D. 273 K

Answer: (B)

Verified step by step guidance

1. Understand that the question is asking about the temperature at which atomic and molecular motion theoretically ceases, which relates to the concept of absolute zero in thermodynamics.
2. Recall that temperature scales like Celsius (°C) and Kelvin (K) are used to measure temperature, but Kelvin is the absolute temperature scale starting at absolute zero.
3. Know that absolute zero is defined as 0 K, which corresponds to -273.15 °C, and at this temperature, the kinetic energy of particles is minimal, meaning their motion theoretically stops.
4. Recognize that 0 °C and 273 K correspond to the freezing point of water, not the cessation of atomic motion.
5. Conclude that the correct temperature where atomic and molecular motion theoretically stops is 0 K, also known as absolute zero.