Calculate the formula (molar) masses of the following chemicals: 1) BeCl2 2) FeCl3 3) CCl2F2 4) Mg(OH)2 5) UF6 6) H3PO4 7) (NH4)2SO4 8) CH3COOH 9) Pb(NO3)2 10) Ga2(SO3)3
The Correct Answer and Explanation is:
Let’s calculate the molar masses for each of the given compounds. We’ll sum the atomic masses of the individual elements in each formula.
BeCl2 (Beryllium chloride):
Atomic mass of Be = 9.012 g/mol
Atomic mass of Cl = 35.45 g/mol
Molar mass = (1 × 9.012) + (2 × 35.45) = 9.012 + 70.90 = 79.912 g/mol
FeCl3 (Iron(III) chloride):
Atomic mass of Fe = 55.85 g/mol
Atomic mass of Cl = 35.45 g/mol
Molar mass = (1 × 55.85) + (3 × 35.45) = 55.85 + 106.35 = 162.20 g/mol
CCl2F2 (Dichlorodifluoromethane):
Atomic mass of C = 12.01 g/mol
Atomic mass of Cl = 35.45 g/mol
Atomic mass of F = 18.998 g/mol
Molar mass = (1 × 12.01) + (2 × 35.45) + (2 × 18.998) = 12.01 + 70.90 + 37.996 = 120.906 g/mol
Mg(OH)2 (Magnesium hydroxide):
Atomic mass of Mg = 24.305 g/mol
Atomic mass of O = 16.00 g/mol
Atomic mass of H = 1.008 g/mol
Molar mass = (1 × 24.305) + (2 × 16.00) + (2 × 1.008) = 24.305 + 32.00 + 2.016 = 58.321 g/mol
UF6 (Uranium hexafluoride):
Atomic mass of U = 238.03 g/mol
Atomic mass of F = 18.998 g/mol
Molar mass = (1 × 238.03) + (6 × 18.998) = 238.03 + 113.988 = 352.018 g/mol
H3PO4 (Phosphoric acid):
Atomic mass of H = 1.008 g/mol
Atomic mass of P = 30.974 g/mol
Atomic mass of O = 16.00 g/mol
Molar mass = (3 × 1.008) + (1 × 30.974) + (4 × 16.00) = 3.024 + 30.974 + 64.00 = 98.998 g/mol
(NH4)2SO4 (Ammonium sulfate):
Atomic mass of N = 14.007 g/mol
Atomic mass of H = 1.008 g/mol
Atomic mass of S = 32.06 g/mol
Atomic mass of O = 16.00 g/mol
Molar mass = (2 × (1 × 14.007 + 4 × 1.008)) + (1 × 32.06) + (4 × 16.00) = 56.028 + 32.06 + 64.00 = 152.088 g/mol
CH3COOH (Acetic acid):
Atomic mass of C = 12.01 g/mol
Atomic mass of H = 1.008 g/mol
Atomic mass of O = 16.00 g/mol
Molar mass = (2 × 12.01) + (4 × 1.008) + (2 × 16.00) = 24.02 + 4.032 + 32.00 = 60.052 g/mol
Pb(NO3)2 (Lead(II) nitrate):
Atomic mass of Pb = 207.2 g/mol
Atomic mass of N = 14.007 g/mol
Atomic mass of O = 16.00 g/mol
Molar mass = (1 × 207.2) + (2 × (1 × 14.007 + 3 × 16.00)) = 207.2 + 2 × (14.007 + 48.00) = 207.2 + 124.028 = 331.228 g/mol
Ga2(SO3)3 (Gallium(III) sulfite):
Atomic mass of Ga = 69.723 g/mol
Atomic mass of S = 32.06 g/mol
Atomic mass of O = 16.00 g/mol
Molar mass = (2 × 69.723) + (3 × (1 × 32.06 + 3 × 16.00)) = 139.446 + 3 × (32.06 + 48.00) = 139.446 + 3 × 80.06 = 139.446 + 240.18 = 379.626 g/mol
Explanation:
To calculate the molar mass of each compound, you multiply the atomic mass of each element by the number of atoms of that element in the compound’s formula. Then, sum these values for all elements in the compound. The molar mass is essentially the mass of one mole of that compound, and it is expressed in grams per mole (g/mol). This value is crucial in stoichiometry, where you need to convert between moles, mass, and other quantities.
