A 1.8 mole sample of a compound weighs 195 g and is found to be 11.18% H and 88.82% C. What is the molecular formula for the compound?

C8H12

Explanation:

First find the molar mass

195/1.8 × 1 = 108.3 gmol-1

Then the molecular formula

Mass of C in 1 mole of compound = 88.82×108.3/100

= 96.2 g

Mass of H in 1 mol of.the compound = 108.3×11.18/100 = 12.11 g

Divide the mass by their molar masses to get no. of moles in 108.3 g of compound or 1 mole of compound

Moles of C in one Mole of compound = 96.2g/12 gmol-1 = 8 mol

Moles of H in 1 mole of compound = 12.11g/1 gmol-1 =12 mol

Since we need the molecular formula it's C8H12