20. liquid nitrogen boils at 77.2 k. what is this temperature in degrees celsius?

Explanation:

Step1: Recall temperature - conversion formula

The formula to convert from Kelvin (K) to Celsius ($^{\circ}C$) is $T_{C}=T_{K}- 273.15$, where $T_{C}$ is the temperature in Celsius and $T_{K}$ is the temperature in Kelvin.

Step2: Substitute the given value

Given $T_{K} = 77.2$ K. Substitute it into the formula: $T_{C}=77.2 - 273.15$.

Step3: Calculate the result

$T_{C}=77.2-273.15=-195.95^{\circ}C$

Answer:

$-195.95^{\circ}C$