How do you express 275 mmHg in atm. and Pascal?
Of course, pressure is not measured in millimetres of mercury, but in force per unit area. If you go thru the math, and I don't propose to do so, it turns out that a column of mercury
The use of a mercury barometer to measure pressures is of long standing. It was a very convenient means to measure small pressures when doing a distillation. Most laboratories would have an old (usually beautifully made) mercury barometer somewhere on their premises.
These days, the use of mercury is not so prevalent due to environmental concerns. Mercury in the lab tends to be fascinating, and sometimes students play with it, i.e. float coins on it, use it for electrical switches, dissolve alkali metals in it (I know I did). Inevitably, it all goes pear shaped, and you spill mercury on the floor or the desk, where it inhabits every crack. Water barometers are not so popular, because
275 mm Hg = 0.36 atm or 36477 pa
1 atm = 760 mm Hg
We can write the two conversion factors
1 atm / 760 mm Hg or 760 mm Hg / 1 atm
275 mm Hg x (1 atm \ 760 mm Hg)
1 atm = 101325 pa
We can write two conversion factors
1 atm / 101325 pa or 101325 pa / 1 atm
0.36 atm x ( 101325 pa / 1 atm )