National League for Nursing (NLN PAX) Practice Exam

At what temperature does water freeze on the Kelvin scale?

1. 273 K

2. 0 K

3. 100 K

4. 32 K

The correct answer is: 273 K

Water freezes at 0 degrees Celsius, which corresponds to 273.15 K on the Kelvin scale. The Kelvin scale is an absolute temperature scale that starts at absolute zero, which is 0 K, the theoretical point at which all molecular motion stops. The conversion from Celsius to Kelvin involves adding 273.15 to the Celsius temperature. Thus, when water transitions from a liquid to a solid state at its freezing point, the temperature on the Kelvin scale is approximately 273 K. The other temperature points listed do not correspond to the freezing point of water. Absolute zero, indicated by 0 K, represents the lowest possible temperature where molecular activity is minimal. The temperatures 100 K and 32 K are significantly below water's freezing point, with 100 K being close to the temperature that may not sustain water in its liquid form.