Presentation on theme: "MOLAR MASS The molar mass is the mass, in grams, of one mole (6.02 1023 particles) of an element (ion), a covalent molecule or a formula unit. molar."— Presentation transcript:
1 MOLAR MASSThe molar mass is the mass, in grams, of one mole (6.02 1023 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)
2 MASS of one MOLEGram 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.
3 gam, gfm, gmm examples:Problem: Give the gram atomic mass of hydrogen.Solution: H = 1H = 1(1.01) = 1.01 g/molProblem: Give the gram molecular mass of hydrogen.Solution: H2 = 2H = 2(1.01) = 2.02 g/molProblem: Find the gram formula mass for H2SO4.Solution: H2SO4 = 2H + 1S + 4O= 2(1.01) (16.00) = g/mol
4 Molar Mass … a.k.a. Molecular Weight (MW) molar mass = mass of 1 mole of substanceMolar mass can be determined by adding up the atomic masses from the periodic table (atomic mass goes to 2 decimal places).
5 MW Example 1: = 1C + 4H = 12.01 + 4(1.01) = 16.05 g CH4/mol CH4 Find the MW of CH4.= 1C + 4H= (1.01)= g CH4/mol CH4
6 MW Example 2: =Mg + 2O + 2H =24.31 + 2(16.00) + 2(1.01) 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
7 MW Example 3: Find the MW of MgSO4∙7H2O. =Mg + S + 4O + 7(H2O) = (16.00) + 7( )= g MgSO4∙7H2O /mol MgSO4∙7H2O
9 Mole Mass Calculations 1 mole = molar mass (MW) in gramsMassMOLE
10 Mass Example 1:How many grams are in 7.20 moles of dinitrogen trioxide?dinitrogen trioxide = N2O3MW of N2O3 = 2N + 3O = 2(14.01) + 3(16.00) = g/mol1 mole = g N2O3
11 MW of Fe2O3 = 2Fe + 3O = 2(55.85) + 3(16.00) = 159.70 g/mol Mass Example 2:Find the number of moles in 92.2 g of iron(III) oxide.iron(III) oxide = Fe2O3MW of Fe2O3 = 2Fe + 3O = 2(55.85) + 3(16.00) = g/mol1 mole = g Fe2O3
12 Make sure you write out all work and include all units!! Practice WorksheetDo #1-10 on Mole and Mass WSMake sure you write out all work and include all units!!