University:
Kentucky State University
Course:
CHE 101 | General Chemistry I
Academic year:

2022
Views:

237

Pages:

7
Author:

Maverick Martin

Atomic weight scale and molecular weight Atomic weight scale and Mole 12C atom was considered to contain 12 Atomic Mass Unit. • 12 g of 12C was considered to represent 1 Mole of 12C • 1 Mole of 12C contains 6.022×1023 of 12C atoms. This number is called Avogadro’s number • Atomic weight scale and Mole Mole of an element: • One mole of any element has a mass in grams equivalent to the atomic mass weight of this element. For example, 1 mole of sodium = 22.989 gm ≈ 23 gm • One mole of any element contains Avogadro’s number of that element atoms. Atomic weight scale and Mole Mole of a compound (includes diatomic elements): - One mole of any compound with a molecular formula of AXBY has a mass in grams equivalent to the sum of mass weights of its atoms = (X × A atomic mass) + ( Y × B atomic mass) → (Molecular weight or relative molecular mass, Mr). - One mole of any compound has a mass in grams equivalent to its molecular weight - One mole of any compound contains Avogadro’s number of that compound molecules Molecular weight calculations - Write the chemical formula - Get the atomic mass for each element (from periodic table) - Multiply each element by the number of its atoms in molecule - Sum the masses of resulting products together. Express the resulting figure by gram → Molecular weight - Example: Water: H2O Mole= (2 × 1.008) + (1 × 15.999 )=18.015g Mole Calculations • Calculate Mole of the following: - CO2 - CH4 - CH3OH Use the following atomic masses: C=12, H=1, O=16 Mole Calculations Calculate Mole of the following: CO2 (1×12)+(2×16) →44g CH4 (1×12)+(4×1)→16g CH3OH (1×12)+(4×1)+(1×16)→32g Use the following atomic masses: C=12, H=1, O=16