How many moles of sucrose, C12H22O11, are in a 25 g sample? Use C = 12.01, H = 1.008 and O = 16.00 g/mol.

1. First build the molar mass of sucrose from its formula. 2. Carbon contributes 12 x 12.01 = 144.12 g/mol. 3. Hydrogen contributes 22 x 1.008 = 22.18 g/mol. 4. Oxygen contributes 11 x 16.00 = 176.00 g/mol. 5. The molar mass is 144.12 + 22.18 + 176.00 = 342.30 g/mol. 6. Now divide: 25 g / 342.30 g/mol = 0.073 mol of sucrose. 7. The value 0.73 mol is the same digits shifted one decimal place, a common slip when the divisor is in the hundreds. 8. The value 13.7 mol inverts the division and reports molar mass over mass instead. _Source: OpenStax Chemistry (CC BY 4.0), Ch 3 "Composition of Substances and Solutions", section 3.1 Formula Mass and the Mole Concept_