Cute asked in Science & MathematicsChemistry · 7 months ago

# Why must only SI units be used when making calculation using the ideal gas equation?

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• alan P
Lv 7
7 months ago

You can use any set of consistent units

• Anonymous
7 months ago

Why must?

the short answer is you don't.

• 7 months ago

you can use any units you want as long as you use the value of the gas constant that applies to those units.

reference has a list of 20 or so values for R, including ones with temp in rankine, and volume in cubic feet.

https://www.cpp.edu/~lllee/gasconstant.pdf

• pisgahchemist
Lv 7
7 months agoReport

I agree with billrussell. You can use any number of units for P, V and T, as long as you've got R defined in those units. The atmosphere (atm) isn't an SI unit and we use it all the time. The SI unit for pressure is the pascal.

• Zirp
Lv 7
7 months ago

So people from around the world can read and understand what you calculated and noted

• 7 months ago

Primarily because that's the way it is taught. The equation still holds, but the units are very different. and the arithmetic is a bit trickier, even though the same equation still holds.

Imperial (or English) units can be used as in:

https://www.me.psu.edu/cimbala/Learning/General/Ga...

• 7 months ago

The constant R is 22.4 liters divided 273˚K

R = 22.4 ÷ 273

This is approximately 0.08205. 22.4 is the number of liters of one mole of a gas at standard temperature and pressure.

P * V = n * R * T

P is in atmospheres. V is in liters. n is the number of moles. T is the temperature in ˚K. If we used different units, the value of the ideal gas constant would have to be different.