Student_03_3

# Student_03_3 - ACTIVITY 03-3 Mole and Molar Mass WHY To...

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39 W HY ? To keep track of the huge numbers of atoms and molecules in samples that are large enough to see, chemists have established a unit of counting called the mole (abbreviated mol) and a unit of measure called the molar mass , which has units of g/mol. By using the idea of a mole and molar mass , you will be able to count out speci f c numbers of atoms or molecules simply by weighing them. This capability is necessary in understanding chemical reaction equations, conducting research in chemistry and biology, and applying chemistry in technology and the health sciences. L EARNING O BJECTIVES Understand the relationship between the mole and Avogadro’s number Understand the meaning of the molar mass of a substance Recognize that the molar mass is an average of all the isotopic masses of an element S UCCESS C RITERIA Quickly convert between the number of atoms, moles, and the mass of a sample by using Avogadro’s number and the molar mass appropriately Calculate the molar mass from isotopic abundances and isotopic masses P REREQUISITES Activity 01-2: Unit Analysis Activity 01-3: Signi f cant Figures in Data Activity 02-1: Atoms, Isotopes, and Ions M ODEL 1: A M OLE IS A C OUNTING U NIT 1 pair of objects = 2 objects 1 dozen objects = 12 objects 1 gross of objects = 144 objects 1 mole of objects = 6.02214 × 10 23 objects Mole and Molar Mass A CTIVITY 03-3

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Chapter 3: Molecules and Compounds 40 Foundations of Chemistry K EY Q UESTIONS 1. How many pencils are there in a dozen pencils?
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## This note was uploaded on 09/19/2011 for the course CHE 1112R taught by Professor Meghee during the Fall '11 term at St. Johns Duplicate.

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Student_03_3 - ACTIVITY 03-3 Mole and Molar Mass WHY To...

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