Basic units of thermodynamics
Mass——– kg.
Mole—— The mole is
the amount of substance that contains as many atoms (or molecules)
as there are atoms in 0.012 kg of carbon-12. Length—m.
Time: second
SI unit of temperature is Kelvin (abbreviated as K). The Kelvin is
defined as the fraction of 1/273.16 of the thermodynamic temperature of the
triple point of water. The relation between Kelvin and Celsius temperature is K
= C + 273.15 (The triple point of water is at 0.01 C).
Derived units: Force: 1 N = 1 kg m/s2, pressure 1 Pa = 1
N/m2, 1 bar = 10 Pa, 1 atm. = 101325 Pa.
In thermodynamics we are
concerned with absolute pressure.
Gauge pressure = absolute pressure –
atmospheric pressure.
Ordinary vacuum gauge pressure = atmospheric pressure –
absolute pressure.
