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## Main Question or Discussion Point

Hi, I'm doing a question about Boyles law, and I don't understand some of the units they are giving.

Initial pressure = 20kN/m^2 (gauge) = 20kPa (gauge)

Initial volume = 47 volumetric units

Final pressure = 120kN/m^2 = 120kPa

Final volume = ?

(The barometric pressure was 762mm Hg)

I don't understand the units 762 mm Hg, and why they say (gauge) in brackets. I think it has something to do with a manometer, but I'm only used to working with Pa so far.

I'm guessing volumetric units could be anything, because the units probably cancel out when you put them into the equation, so only the ratio between the initial and final volumes is significant?

Thanks

Initial pressure = 20kN/m^2 (gauge) = 20kPa (gauge)

Initial volume = 47 volumetric units

Final pressure = 120kN/m^2 = 120kPa

Final volume = ?

(The barometric pressure was 762mm Hg)

I don't understand the units 762 mm Hg, and why they say (gauge) in brackets. I think it has something to do with a manometer, but I'm only used to working with Pa so far.

I'm guessing volumetric units could be anything, because the units probably cancel out when you put them into the equation, so only the ratio between the initial and final volumes is significant?

Thanks