Lesson 1: Mole Concept

MOLE

• is the particular unit to quantify atoms, molecules, and ions

• the SI Unit for the amount of the substance

• 1 mole = 6.022×10²³

• the amount of substances that contains the avogrado’s number

ATOMIC MASS

• is measured in atomic unit (amu or u), a relative unit based on the avlue of exactly 12 for the C-12 isotope

• the atomic mass of hydrogen is 1.008u because its 12 times less massive than C-12

• the atomic mass of gold is 197u, because it is 16.41 times as massive as C-12

• the atomic mass of magnesium is 24.31u, because it is approximately 2 times heavier than C-12

AVERAGE ATOMIC MASS

• the atomic mass of an element is the average atomic mass of the naturally occuring of the isotope by its fractional abundance

• ave. atomic mass (isotopic mass x % abundace) + (…)

RELATIVE ATOMIC MASS

• is the ratio of the average atomic mass of an atom to one atomic mass unit (amu)

• similar to average atomic mass but doesn’t have a unit

AVOGRADO’S NUMBER

• a principle stated in 1811 by the Italian chemist Amadeo Avogrado (1776-1856) that equal volume of gases at the same temperature and pressure contain the same number of molecules regardless of their chemical nature and physical nature

• 1 mole of an element is numerically equal to its atomic mass expressed in grams

• 1 mole of an element contains 6.02×10²³ atoms

• 1 mole of molecular compound contains 6.02×10²³ molecules

• 1 mole of ionic compounds contain 6.02×10²³ cations and 6.02×10²³ anions

MOLAR MASS

• is the mass in grams of one mole of a substance

• is obtained by multiplying the number of atom by the atomic mass of each element