What is the molar mass of a compound given that 0.035g of the gaseous compound occupies 30cm3 at r.t.p

Answer 1

To find the molar mass of a compound, we can use the ideal gas law equation:

PV = nRT

Where:
P = pressure (atmospheres)
V = volume (liters)
n = number of moles
R = ideal gas constant (0.0821 L.atm/mol.K)
T = temperature (Kelvin)

At r.t.p. (room temperature and pressure), the temperature is 273.15 Kelvin and the pressure is 1 atmosphere.

We are given:
Mass = 0.035g
Volume = 30cm^3 (which is 0.03L)

First, we need to convert the mass from grams to moles using the molar mass formula:

Molar mass = mass / moles

Let's assume that the molar mass is M grams/mol. Then we can solve for moles:

moles = mass / M

We know that 1 mole of any gas at r.t.p. occupies 22.4 L, so we can rewrite the ideal gas law equation as:

P * V = n * R * T
1 * 0.03 = (mass / M) * 0.0821 * 273.15

Now, we can rearrange the equation to solve for M:

M = (mass * R * T) / (P * V)

Substituting the given values:

M = (0.035 * 0.0821 * 273.15) / (1 * 0.03)

M = 5.459 g/mol

Therefore, the molar mass of the compound is approximately 5.459 g/mol.