A gas has an empirical formula of POF3. If 0.350L of the gas at STP has a mass of 1.62g, what is the molecular formula of the mass?
molar mass= 1mol x 22.4L/1mol x 1.62g/0.350L = 103.7g
molarmass/empirical formula mass = 103.7g/214.5g = 0.4834 ...
how do I find the molecular mass?
thanks in advance
how do i find the molecular formula*
The empirical formula mass of POF3 is close to 104 if I added correctly. That means 1 empirical unit to a molar mass unit. So 103.7 is the molar mass. I don't know how you arrived at 214.5
Ah, I see my error.
I used the molar mass of iron rather than fluorine, thanks.
To find the molecular formula of the gas, you need to determine the molecular mass. The empirical formula of POF3 tells you the relative ratio of atoms in the molecule, but it does not provide the actual number of atoms in the molecule.
To find the molecular mass, you can follow these steps:
1. Start by calculating the molar mass of the empirical formula. Determine the molar mass of each element in the empirical formula and then multiply it by the number of atoms of that element in the formula.
In this case, the molar mass of one phosphorus atom (P) is 30.97 g/mol, the molar mass of one oxygen atom (O) is 16.00 g/mol, and the molar mass of one fluorine atom (F) is 19.00 g/mol.
So, the molar mass of POF3 = (30.97 g/mol x 1 atom of P) + (16.00 g/mol x 1 atom of O) + (19.00 g/mol x 3 atoms of F) = 30.97 g/mol + 16.00 g/mol + 57.00 g/mol = 103.97 g/mol.
2. Next, divide the given molar mass (103.7 g/mol) by the molar mass of the empirical formula (103.97 g/mol) to find the whole number ratio between them.
Molar mass ratio = 103.7 g/mol / 103.97 g/mol = 0.996
3. Compare the molar mass ratio with the subscripts in the empirical formula.
The molar mass ratio of 0.996 is very close to 1, which suggests that the empirical formula might already be the molecular formula. In other words, the molecular formula of the gas is likely the same as the empirical formula: POF3.
So, in this case, the molecular formula is the same as the empirical formula, POF3.