Okay... so entropy is dimensionless, but the change in entropy is in Joules per degree? This is why I call it "thermodagnabbits."Look up the second law of thermodynamics.
Quite so.But temperature is not a measurement of energy, is it?
Quite so.
studiot said:Temperature is a state variable, with its own dimensions - °K
studiot said:Entropy is Joules per °K
It is, but not total energy, as I said beore, it's a measure of average enegry. Although, given some other specifics total energy can certainly be expressed as a function of temperature.But temperature is not a measurement of energy, is it?
It takes more energy to raise the temperature of a gram of water from 0C to 1C than a gram of copper at the same temperatures. And it takes more energy to raise the temperature of a metric ton of X from 0C to 1C than it does to raise the temperature of a milligram of X by the same amount.
Feel free to develop this idea.Relating kinetic energy to pressure and using the ideal gas law you can easily show that the only thing separating temperature from an expression for average energy is an equal sign and an arbitrary constant.
But don't different substances have different specific heats? Doesn't the same ratio of Joules/mole leave water at a lower Kelvin temperature than silicon?you say, but since T is given arbitrary units, R is only there for that purpose. You could give T units of Joules/mole and you would not need R at all.
As studiot observed, Joules/mole are the units that correspond to the expression that relates to an ideal gas. It would be an appropriate approximation for the gaseous states of water and silicon. The expression would change considerably for a solid or a liquid because the thermal energy would be apparent in ways other than just translational movement. The final expressions for real liquids and solids would have several terms, but each would be in units of average energy, just different units.But don't different substances have different specific heats? Doesn't the same ratio of Joules/mole leave water at a lower Kelvin temperature than silicon?
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