A 170.0 g sample of an unidentified compound contains 29.84 g sodium, 67.49 g chromium, and 72.67 g oxygen. What is the compound's empirical formula?

The empirical formula : Na₂Cr₂O₇

Given

170 g sample contains :

29.84 g sodium, 67.49  g chromium, and 72.67 g oxygen

Required

The compound's empirical formula

Solution

mol ratio of elements :

Na : 29.84 : 23 g/mol = 1.297

Cr : 67.49 : 51,9961 g/mol = 1.297

O : 72.67 : 16 g/mol = 4.54

Divide by 1.297

Na : Cr : O = 1 : 1 : 3.5 = 2 : 2 : 7

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.