Question

A gaseous compound has a density of 1.87 g/L at 26.8 °C and 1.83 atm. What is the molar mass of the compound? molar mass:

Answer 1

25.15g/mol

Step-by-step explanation:

To solve this question, we say

PV = nRT..........formula 1

Where P= pressure = 1.83atm

V = volume

n= number of moles

R = General gas constant = 0.0821 Latm/Kmol

T = Temperature = 26.8 + 273 = 299.8K

However, Density (D) = number of moles (n) / volume (V)........ formula 2

Also, number of moles (n) = mass (m) / molar mass (MM).........formula 3

- Rearranging the formula 2, we have:

mole (m) = density × volume

- Rearranging formula 3, we have:

mass (m) = molar mass × moles

This means that;

Density = mole × molar mass/volume

Volume = number of moles (n) × molar mass(MM) / density(d)

Inserting into PV=nRT

PnMM/d = nRT

Divide both sides by n

PMM/d = RT

Molar mass (MM) = D.R.T / P

Molar mass = 1.87 × 0.0821 × 299.8 / 1.83

Molar mass = 46.0273946/1.83

Molar mass = 25.15g/mol