A compound containing only sulfur and nitrogen is 69.6% S by mass; the molar mass is 184 g/mol. What are the empirical and molecular formulas of the compound?
i solved for empirical and got a 1:1 ratio so it would be SN.
for the molecular do i take 184/46.08 to get 3.99 or 4?
so it would be S4N4?
Yes, assuming the S is reported as %S (as you have it written) and not %S8.
You are correct in determining the empirical formula as SN based on the 1:1 ratio of sulfur to nitrogen atoms.
To find the molecular formula, you need to compare the molar mass of the empirical formula (SN) to the given molar mass of the compound (184 g/mol).
The molar mass of SN (sulfur: atomic mass = 32.06 g/mol, nitrogen: atomic mass = 14.01 g/mol) is:
(32.06 g/mol) + (14.01 g/mol) = 46.07 g/mol
To determine how many empirical formula units are in the molecular formula, you divide the molar mass of the compound (184 g/mol) by the molar mass of the empirical formula unit (46.07 g/mol):
184 g/mol รท 46.07 g/mol = 4
Therefore, the molecular formula for the compound is S4N4, which contains four empirical formula units of SN.
To determine the empirical formula of the compound, you correctly found that the ratio of sulfur (S) to nitrogen (N) is 1:1, which gives the empirical formula SN. The empirical formula represents the simplest whole-number ratio of atoms present in a compound.
Now, to find the molecular formula, you need to compare the molar mass of the compound to the empirical formula mass.
The molar mass of the compound is given as 184 g/mol. The empirical formula mass can be calculated by adding the atomic masses of sulfur and nitrogen:
Empirical formula mass = (atomic mass of sulfur) + (atomic mass of nitrogen) = (32.06 g/mol) + (14.01 g/mol) = 46.07 g/mol
To determine the number of empirical units present in the molecular formula, divide the molar mass of the compound by the empirical formula mass:
Number of empirical units = (molar mass of compound) / (empirical formula mass) = 184 g/mol / 46.07 g/mol = 3.99
Since the number of empirical units is approximately 3.99, you can round it up to the nearest whole number, which gives 4. This means that the molecular formula of the compound is (SN)4, which corresponds to S4N4.