Her behavior has been reinforced (i.e. strengthened). Reinforcement can be external or internal and can be positive or negative. If a child wants approval from parents or peers, this approval is an external reinforcement, but feeling happy about being approved of is an internal reinforcement.
It remained to define the unit of amount of substance by fixing the corresponding mass of carbon 12; by international agreement, this mass has been fixed at 0.012 kg, and the unit of the quantity amount of substance was given the name mole (symbol mol).
DEFINITION: Molar Mass is the mass in grams of 1 mole of a substance and is given the unit of g mol-1 molar gas volume (gas volume per mole, units dm3 molâ1) . This is the volume of 1 mole of a gas at a given temperature and pressure. All gases have this same volume. At room pressure (1at m) and room temperature 25oC the molar gas volume is 24 dm3 molâ1