Mole and Molar Mass - PageOut

Mole and Molar MassWhy?The concepts of mole and molar mass allow specific numbers of atoms ormolecules to be selected. It is necessary to know how many atoms ormolecules are present in different amounts of material in order to learn, andapply to real-world problems, additional concepts in chemistry, physics,biology, engineering and the health sciences.Learning Objectives• Understand the concepts of mole and molar mass.• Relate the number of atoms, molecules, moles and the mass of a sampleto each other.Success Criteria• Quickly relate the mass of a substance and the number of atoms,molecules and moles present.ResourcesChang/Overby (General Chemistry, McGraw Hill, 2011) pp. 62-68.PrerequisitesUnit conversion, SI units and abbreviations, significant figures, atomicmass, atoms and isotopes.New ConceptsAvogadro’s number, mole, molar mass.DefinitionsIn your own words, write definitions of the terms in the New Conceptsection.

Skill Exercises1. If one apple has a mass of 0.15 kg, calculate the mass of a dozen applesand the mass of a mole of apples.2. Determine how many carbon-12 atoms are in a sample that has a mass of6.00 g.3. Calculate the mass in grams of one carbon-12 atom in two ways: from themolar mass in grams and from the atomic mass in amu.Note: 1 amu = 1.66054 x 10 -24 g.3

Problems1. Which has more atoms: 24.02 g of carbon or 56.18 g of silicon? Explain.2. What is the mass of 2.5 moles of carbon dioxide, and how many CO 2molecules are in this quantity?3. A natural sample of nitrous oxide, N 2 O, has a mass of 128 g. Calculate thefollowing quantities:a. The molar mass of N 2 Ob. Moles of N 2 O molecules in this samplec. Number of N atoms in this sample4