Final answer:
The unit used in energy calculations in thermodynamics is the joule (J), which is equivalent to kg·m2/s2. This unit is applicable for various forms of energy and is also used for measuring heat and work.
Step-by-step explanation:
The unit used in energy calculations in thermodynamics is the joule (J). In the International System of Units (SI), the joule is the standard unit of energy. It is derived from the basic units by the equation for kinetic energy, and is represented as kg·m2/s2. It makes sense as it looks like mass times velocity-squared. Various forms of energy, such as thermal, radiant, and chemical, can all be expressed using the joule. Additionally, heat and work, which result in changes in energy, are also measured in joules. The common unit conversions in thermodynamics also revolve around the joule, further emphasizing its relevance and ubiquity in energy-related calculations.
For example, confirming that the units of nRT (where R is the gas constant and has different values depending on the units) are those of energy, we can see that 8.31 J/mol·K is one such value for R. Therefore, in thermodynamics, calculations dealing with energy typically utilize the joule or its multiples such as kilojoules (1 kJ = 1000 J).