Originally Posted by
DiabloScott
Not redundant. 5 dozen eggs is not the same as 5 eggs, and n moles of particles is not the same as n particles. You're trying to find a loophole to save your error - I advise capitulation.
I used number of particles to simplify my statement. No 5 dozen eggs isn’t the same as 5 eggs but it is the same as 60 eggs. Saying you have 6.02 x 10^23 particles
is the same as saying that you have n moles. Most people don’t know the concept of “mole” so saying “number of particles” is just as valid. I made no error.
Bourdon tube gauges are less susceptible to ambient pressures, but not immune - and I've never seen a Bourdon tube gauge that reads psia... show me one and I'll eat my comment. Most Pabs gauges are for use in highly sensitive lab instruments and use a reference chamber that is not susceptible to atmospheric fluctuations. This has nothing to do with bike tires of course.
You mean like
like this one?
Me too, doing mechanical engineering. I've also used them at XXXX feet below sea level (confidential information). Do your gauges have a pin that keeps the dial from going below zero?
Some do have a pin and some don’t. I’ve used gauges on vessels that I’ve had to apply a vacuum to prior to a procedure and the gauge showed negative pressure. At rest, the gauge showed no inclination to be below zero, however. Most of the gauges have a fairly large range of pressure…some up to thousands of psi so a 2 psi difference isn’t going to move the needle.
This is fun bickering - but defining mole and bourdon tube to an engineer is condescending... (that means talking to people like they're stupid).
I have no idea who you are or what you do. 99.9% of the population has only had a passing exposure to the concept of a mole with the vast majority of those never having had any exposure. A larger percentage have no idea what a bourdon tube is.
My redefining a mole to you was to point out you are in error about the concept. “n” in the ideal gas law is the number of moles. But, because the number of particles is equivalent to the number of moles, “particles” can be substituted for moles. Of course, the units on the gas constant would have to be changed in a calculation. “Moles” is a short hand that is easier to deal with but stating the number of particles
is correct.
From a historical context, Avogadro’s Law states the “amount of gas”. Avogadro develop his law in 1812 but the Avogadro’s number (6.02 x10^23 particles) wasn’t established until 1909. The Ideal Gas Law was described in 1834. The concept of a “mole” wasn’t described until 1900. People used other units prior to the discovery of the mole and Avogadro’s number. We just use the mole as short hand.