Final answer:
In Chemistry, the molar mass, expressed in grams per mole, is used as the conversion factor between grams and moles, using dimensional analysis for mole-mass conversions.
Step-by-step explanation:
In Chemistry, when converting between grams and moles, the specific value used is the molar mass of the substance. The molar mass is defined as the mass in grams of one mole of representative particles, such as atoms, molecules, or formula units for ionic compounds. It is expressed in units of grams per mole (g/mol) and is vital for performing mole-mass conversions.
To convert grams to moles, you would use the reciprocal of the molar mass as a conversion factor. Conversely, to convert from moles to grams, you use the molar mass directly. For example, to find the mass of 0.50 mole of molecular hydrogen (H2), you would multiply 0.50 moles by the molar mass of H2. This process often involves dimensional analysis to ensure that units cancel appropriately and that the calculation is correct.