Presentation on theme: "MOLAR MASS The molar mass is the mass, in grams, of one mole (6.02 10 23 particles) of an element (ion), a covalent molecule or a formula unit. molar."— Presentation transcript:
MOLAR MASS The molar mass is the mass, in grams, of one mole ( particles) of an element (ion), a covalent molecule or a formula unit. molar mass (MM)gram atomic mass (gam) molecular weight (MW)gram molecular mass (gmm) formula mass (FM)gram formula mass (gfm) formula weight (FW)
MASS of one MOLE Gram atomic mass (gam): the atomic mass (the mass in one mole of a substance) of an element expressed in grams. Gram molecular mass (gmm): the atomic mass of one mole of a molecular compound. Gram formula mass (gfm): the sum of the atomic masses of the atoms that are in the formula of a compound.
gam, gfm, gmm examples: Problem: Give the gram atomic mass of hydrogen. Solution: H = 1H = 1(1.01) = 1.01 g/mol Problem: Give the gram molecular mass of hydrogen. Solution: H 2 = 2H = 2(1.01) = 2.02 g/mol Problem: Find the gram formula mass for H 2 SO 4. Solution: H 2 SO 4 = 2H + 1S + 4O = 2(1.01) (16.00) = g/mol
Molar Mass … a.k.a. Molecular Weight (MW) molar mass = mass of 1 mole of substance Molar mass can be determined by adding up the atomic masses from the periodic table (atomic mass goes to 2 decimal places).
MW Example 1: Find the MW of CH 4. = 1C + 4H = (1.01) = g CH 4 /mol CH 4
MW Example 2: Find the MW of Mg(OH) 2. =Mg + 2O + 2H = (16.00) + 2(1.01) =58.33 g Mg(OH) 2 /mol Mg(OH) 2
MW Example 3: Find the MW of MgSO 47H 2 O. =Mg + S + 4O + 7(H 2 O) = (16.00) + 7( ) = g MgSO 4 7H 2 O /mol MgSO 4 7H 2 O
Calculations: Use Mole Map to help calculate
Mole Mass Calculations 1 mole = molar mass (MW) in grams Mass
Mass Example 1: How many grams are in 7.20 moles of dinitrogen trioxide? MW of N 2 O 3 = 2N + 3O = 2(14.01) + 3(16.00) = g/mol 1 mole = g N 2 O 3 dinitrogen trioxide = N 2 O 3
Mass Example 2: Find the number of moles in 92.2 g of iron(III) oxide. MW of Fe 2 O 3 = 2Fe + 3O = 2(55.85) + 3(16.00) = g/mol 1 mole = g Fe 2 O 3 iron(III) oxide = Fe 2 O 3
Practice Worksheet Do #1-10 on Mole and Mass WS Make sure you write out all work and include all units!!