University:
Georgia Southern University
Course:
CHEM 1310 | Comprehensive General Chemistry
Academic year:

2024
Views:

228

Pages:

1
Author:

Jalen W.

Primer for Mole & Atomic Mass, Molecular Mass Molecular Formula A. The Mole • It’s a unit of measures, like a baker’s dozen (13), a gross (144) or pair (2). • A mole has 6.022 x 1023 units and this number is often referred to as Avogadro’s Number. • Avogadro’s Number is an experimentally determined value. B. Relationship between mole and mass: • Moles have different mass not different number of units or pieces. • Every mole contains 6.022 x 1023 units but not all 6.022 x 1023 quantities have the same mass. o For example: One mole of hydrogen atoms has a mass of 1.007 grams and contains 6.022 x 1023 atoms of hydrogen. One mole of carbon atoms has a mass of 12.011 grams and contains 6.022 x 1023 atoms of carbon. • *Problem – solving strategy: Mass < ---------- > moles < --------- > units (atoms, molecules or ions) Mass of sample x (1 mole/molecular mass) = mole of compound (molecule) Mass of sample x (1 mole/atomic mass) = mole of element Moles x (6.022 x 1023 units/1 mole) = units* Unit can be a molecule, or it can be an element. * C. Molecular Mass/Weight is the mass of one mole of molecules of a compound • Molecular Mass (mol mass)/Molecular Weight (mol wt.) has units of grams/mole. Molecular Mass is sometimes referred to as Molar Mass (mol mass). • Molecular masses of compounds are gotten by summing up the atomic mass unit of each of the atoms in the compound. CO2 has a molecular mass of 44.009 grams/mole. This value is obtained as follows: Element Carbon (C) Oxygen (O) Number of Atoms 1 2 Atomic mass unit 12.011 grams 15.999 grams Total mol mass: Total mass 12.011 grams 31.998 grams 44.009 grams