How do you work out the molecular formula?
Generally you convert grams to mols, then find the ratio of the atoms to reach other. But this is all generality. Why don't you post the entire problem, tell us what you know how to do and what you don't understand about it and let us provide some hints to work the problem.
To work out the molecular formula, you need to know the empirical formula and the molar mass of the compound. The empirical formula represents the simplest whole-number ratio of atoms in a compound, while the molecular formula represents the actual number of atoms of each element in a molecule.
Here are the steps to determine the molecular formula from the empirical formula:
1. Find the empirical formula: If you already know the empirical formula, skip this step and proceed to step 2. To determine the empirical formula, you need to know the mass or percent composition of each element present in the compound. From these values, you can calculate the molar ratio of each element in the compound.
2. Calculate the empirical formula mass: Determine the molar mass of the empirical formula by summing up the atomic masses of the elements in the empirical formula. You can find the atomic masses on the periodic table.
3. Determine the molar mass of the compound: If you already know the molar mass of the compound, skip this step and proceed to step 4. To find the molar mass, you can either calculate it based on the known chemical formula or obtain it from experimental data.
4. Calculate the ratio of empirical formula mass to the molar mass: Divide the molar mass of the compound by the empirical formula mass. This gives you the number of empirical formula units in the molecular formula.
5. Multiply empirical formula subscripts by the ratio: Multiply the subscripts of each element in the empirical formula by the ratio obtained in step 4. This will give you the subscripts needed for the molecular formula.
Now that you know the steps involved, if you have a specific problem or question about a molecular formula calculation, provide the necessary details, and I will gladly help you work through it.