1 After each treatment, checking the hair and combing with a nit comb to remove nits and lice every 2â3 days may decrease the chance of selfâreinfestation. 2  Continue to check for 2â3 weeks to be sure all lice and nits are gone.
In chemistry, the molar mass M is a physical property defined as the mass of a given substance (chemical element or chemical compound) divided by the amount of substance. The base SI unit for molar mass is kg/mol. However, for historical reasons, molar masses are almost always expressed in g/mol.
For example, the formula mass of O 2 is 32.00 amu and the molar mass of O 2 is 32.00 g/mol (one mole of O 2 has a mass of 32.00 g). Worked Example 4-3 Calculate the formula mass and molar mass of each of the following: H 2 O, N 2 O 3, and Mg(OH) 2.