Certified Hyperbaric Technologist Practice Test

Which conversion is necessary when changing temperature from Fahrenheit in the context of Charles' Law?

1. To Celsius; subtract 32 degrees, then multiply by 5/9

2. To Kelvin; add 273 degrees

3. To Rankine; add 460 degrees

4. To Kelvin; add 237 degrees

The correct answer is: To Rankine; add 460 degrees

In the context of Charles' Law, which states that the volume of a gas is directly proportional to its temperature in Kelvin, it is crucial to use the Kelvin scale for calculations. This is because gas laws require absolute temperature to relate the physical properties of gases. The correct conversion of Fahrenheit temperature to absolute temperature is to convert it to the Rankine scale, which is analogous to Kelvin but based on Fahrenheit. To do this, one must add 460 degrees to the Fahrenheit temperature. This adjustment allows for the use of an absolute temperature scale while maintaining the original Fahrenheit measurement context. In summary, when using Charles' Law, converting Fahrenheit to Rankine by adding 460 degrees ensures the temperature used aligns with the principles of gas behavior at various temperatures. This is essential for accurate calculations regarding gas volumes under different thermal conditions.