Physical separation techniques use differences in physical properties to separate mixtures into their component substances. Physical separation techniques are not based on molar mass because molar mass is a bulk property of a substance, while physical separation techniques are based on a substance's physical properties.

Molar mass: The ratio of a substance's mass to its amount, which is an average of many instances of the substance. Molar mass is a bulk property, meaning it doesn't depend on the size of the sample. 

Physical properties:Properties that can be observed or measured without changing the substance's identity. These properties include a substance's state of matter, density, melting point, boiling point, and solubility.