Convert 25°C to Kelvin.

• A. 273.15 K
• B. 301 K
• C. 298 K
• D. 273 K

Answer: (B)

Kelvin is obtained from Celsius by adding 273.15, because the size of a degree is the same but the zero point is different. So for 25°C, you add 273.15: 25 + 273.15 = 298.15 K. If you round to the nearest kelvin, that is 298 K. The exact conversion is 298.15 K, which corresponds to about 24.85°C, so 298 K is the appropriate rounded value. The other options reflect different Celsius values: 273.15 K is 0°C, and 301 K is about 27.85°C. The key idea is the 273.15 offset and proper rounding.