L18a-c_Unit_7a-3_ALL[1]

A xed and specic number of grams molar mass 1 mole

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Unformatted text preview: water contains 18 grams of water Calcula<ng the Mw of a compound To calculate the molar mass (molecular weight) of a compound you sum the molar masses of all the atoms that make up the compound. What about the Mw of C16H16F3NO ? 16 C + 16 H + 3 F + 1 N + 1 O 6 C 12.01 1 H 1.008 9 F 19.00 7 N 14.01 8 O 16.00 Mw = 16(12.01 g/mol) + 16(1.008 g/mol) + 3(19.00 g/mol) + 1(14.01 g/mol) + 1(16.00g/mol) = 295.3 g/mol Prac<ce Problem 3 Use the periodic table to determine the molar mass of each of the following compounds and then organize the boxes to accurately match each compound to its molar mass. H2O 18.02 g/mol 58.44 g/mol 342.29 g/mol NaCl C12H22O11 44.02 g/mol 242.22 g/mol N2O C14H10O4 Molar Mass as a conversion factor The Mole represents a deﬁnite & speciﬁed mass of a substance: MOLAR MASS (Molecular Weight) We can use the molar mass to convert between the number of moles of a substance and the number of grams it contains For any element or compound, we can connect the number of moles to the number of grams by using the molar mass as a conversion factor: Number of moles Number of grams Molar Mass as a conversion factor The Mole represents a deﬁnite & speciﬁed mass of a substance: MOLAR MASS (Molecular Weight) Number of moles Number of grams What is the mass in grams of a sample that contains 2.0 moles of sodium? 11 2.0 mol Na 23 grams Na 1 mole Na = 46 grams Na Na 23.00 Molar Mass as a conversion factor The Mole represents a deﬁnite & speciﬁed mass of a substance: MOLAR MASS (Molecular Weight) Number of moles Number of grams How many moles of oxygen are there in sample that contains 42 grams of oxygen? 8 Mw of O2 = 16 g/mol + 16 g/mol = 32 g/mol 42 grams O 2 1 mole O 2 32 grams O 2 = 1.3 moles O2 O 16.00 Prac<ce Problem 4 How many moles of zinc chloride are in a 65.39g sample of zinc chloride (ZnCl2)? 1A 8A 1 H 2A 1.008 3A 4A 5A 6A 2 7...
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