. A compound has a molar mass of 58.14 g/mol. It is 82.6% carbon and 17.4% hydrogen. What is the molecular formula?

Step 1: Determine the number of moles of each element in a 100g sample of the compound.

Since the percentages are given, we can assume that we have a 100g sample of the compound. This means we have 82.6g of carbon and 17.4g of hydrogen.

The molar mass of carbon (C) is approximately 12.01 g/mol and the molar mass of hydrogen (H) is approximately 1.01 g/mol.

So, the number of moles of carbon is 82.6g / 12.01 g/mol = 6.88 mol And the number of moles of hydrogen is 17.4g / 1.01 g/mol = 17.23 mol

Step 2: Determine the simplest ratio of moles of each element.

To find the simplest whole number ratio of moles of each element, divide each by the smallest number of moles calculated. In this case, that's 6.88 mol.

So, the ratio of carbon to hydrogen is 6.88 / 6.88 : 17.23 / 6.88 = 1 : 2.5

Since we can't have half of an atom in a molecule, we multiply these numbers by 2 to get a whole number ratio, which gives us a ratio of 2 : 5.

Step 3: Write the empirical formula.

The empirical formula is the simplest, most reduced ratio of atoms in a compound. Based on our calculations, the empirical formula of this compound is C2H5.

Step 4: Determine the molecular formula.

The molecular formula is a multiple of the empirical formula. The molar mass of the empirical formula C2H5 is (212.01 g/mol + 51.01 g/mol) = 29.07 g/mol.

The given molar mass of the compound is 58.14 g/mol. So, the molecular formula is a multiple of the empirical formula where the multiple, n, is the molar mass of the compound divided by the molar mass of the empirical formula.

n = 58.14 g/mol / 29.07 g/mol = 2

Therefore, the molecular formula of the compound is n (C2H5) = C4H10.