0.23g of volatile liquid occupies 126.4 cc at 27°c and 760 mm pressure,calculate the molecular mass of the liquid

Answer 1

To find the molecular mass of the volatile liquid, we must first determine the number of moles of the substance present.

Using the Ideal Gas Law:

PV = nRT

Where:
P = pressure (760 mm)
V = volume (126.4 cc = 0.1264 L)
n = number of moles
R = ideal gas constant (0.0821 L atm/mol K)
T = temperature (27°C = 300 K)

Plugging in the values:

(760 mm) * (0.1264 L) = n * (0.0821 L atm/mol K) * (300 K)
96.384 = 24.63n
n = 3.92 moles

Next, we calculate the molecular mass of the substance using the formula:

Molecular mass = (mass of substance) / (moles of substance)

Given that the mass of the substance is 0.23g and the moles of substance is 3.92 moles:

Molecular mass = 0.23g / 3.92 moles
Molecular mass = 0.05867 g/mol

Therefore, the molecular mass of the volatile liquid is approximately 58.67 g/mol.