The ice point on the absolute scale of temperature is

Analyze the question: The "ice point" is the temperature at which pure ice melts (pure water freezes) at standard atmospheric pressure. We need its value on the absolute (Kelvin) scale.

Explain the concept: The Kelvin scale starts at absolute zero, the lowest possible temperature. Its degrees are the same size as Celsius degrees, so you convert with:

T(K) = θ(°C) + 273

Solution:

• Ice point on the Celsius scale = 0 °C
• Convert to Kelvin: T = 0 + 273 = 273 K

Checking the other options:

• A. 0 K is absolute zero, which is about −273 °C, not the ice point.
• B. 32 K is a mix-up with 32 °F, the ice point on the Fahrenheit scale.
• C. 100 K is a mix-up with 100 °C, the steam point (boiling point of water) on the Celsius scale.
• D. 273 K is the ice point on the Kelvin scale.

Tip: Remember the pairs below.

• Ice point: 0 °C = 32 °F = 273 K
• Steam point: 100 °C = 212 °F = 373 K

Many students pick 0 K or 32 K because they confuse scales. Always ask yourself, "Which scale is this question using?"