8. Solving a chemistry problem

3. It is known that when a saturated adsorption layer of cerotinic acid (C25H21COOH) is formed at the benzene solution-water interface, the area occupied by 1 surfactant molecule is 29.7 * 10-20 m2, the thickness of the surfactant adsorption layer is 22.99 * 10- 20 m2, surfactant density is 890 kg/m3. Determine the molecular weight of the surfactant.