Amanometer (shown below) that is open to the atmosphere contains mercury (sg = 13.6) with a layer of oil floating on the mercury in the right leg. if the level of the mercury in the left leg is 2 cm above the mercury level in the right leg, and the oil layer on the right is 8 cm above the mercury level in the right leg. what is the density of the oil?

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.