When 2.66 g of phosphorus was burned in chlorine, the product was a phosphorus chloride. Its vapor took 1.77 times as long to effuse as the same amount of CO2 under the same conditions of temperature and pressure. What is the molar mass of the phosphorus chloride? 1. 138 g/mol 2. 102 g/mol 3. 156 g/mol 4. 87.7 g/mol

The molar mass of the phosphorus chloride is 138 g/mol.

Since rates and times are inversely related,

So

Now

= 138 g/mol

Here

The molar mass of CO₂ is 44.01g/mol

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Explanation:

As per Graham's law of effusion and diffusion, the rates of effusion of two gases are inversely related to their molar masses:

Since rates and times are inversely related, you can write

For our case

The molar mass of CO₂ is 44.01g/mol

Subsituting:

Solving:

fe 55.85 g/mol and h2o 18.02 g/mol.