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The Mole. Chapter 11 Chemistry. The Mole. The mole ( mol ) is the SI unit used to measure the amount of a substance. A mole of anything contains 6.02 x10 23 particles. This number is also known as Avogadro’s number. A mole is also equal to the atomic mass of an element in grams.
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The Mole Chapter 11 Chemistry
The Mole • The mole (mol) is the SI unit used to measure the amount of a substance. • A mole of anything contains 6.02 x1023 particles. This number is also known as Avogadro’s number. • A mole is also equal to the atomic mass of an element in grams. • 1.0 mol of carbon is 12.0 g. • 1.0 mol of oxygen gas is 32.0 g.
Converting Moles to Particles • The conversion factor is 1 mol = 6.02 x1023 particles (molecules, atoms, etc.) • Practice Problems • Determine the number of atoms in 2.50 mol of zinc. • Calculate the number of water molecules in 11.5 moles of water. • Convert the number of atoms of the following to moles: a. 5.75 x1024 atoms Al b. 3.75 x1024 molecules CO2 c. 3.58 x 1023 molecules ZnCl2
Mass and the Mole • The mass in grams of one mole of any pure substance is called the molar mass. • The molar mass of any element is numerically equal to its atomic mass and has the units g/mol. • Molar mass is used as a conversion to convert mass of a substance to its molar quantity and its molar quantity to its molar mass.
Practice Problems • Determine the mass in grams of each of the following: • 3.57 mol Al • 42.6 mol Si • 3.45 mol Co • 2.45 mol Zn • Determine the number of moles in each of the following: • 25.5 g Ag • 300.0 g S • 125 g Zn • 1.00 kg Fe
Conversions from Mass to Atoms • When given the mass of a substance to convert to number of atoms use the following steps: • Convert from mass to moles using molar mass. • Convert from moles to number of atoms using 6.02 x1023.
Practice Problems • How many atoms are in each of the following samples: • 55.2 g Li • 0.230 g Pb • 11.5 g Hg • 45.6 g Si • 0.120 g Ti • What is the mass in grams of each of the following: • 6.02 x1024 atoms Bi • 1.00 x 1024 atoms Mn • 3.40 x 1022 atoms He • 1.50 x 1015 atoms N • 5.00 x 1020atoms U