Moles and Molecules: Conversions in Chemistry, Study Guides, Projects, Research of Chemistry

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MOLES & MOLECULES

CONVERSIONS

CHEMISTRY

AVOGADRO’S NUMBER

 AVOGADRO’S NUMBER IS A STANDARD UNIT USED TO COUNT THE NUMBER

OF ATOMS IN A SAMPLE. Bakers use the standard unit dozen to count baked goods. Shoe makers use the standard unit pair to group shoes. DOZEN = 12 PAIR = 2 MOLE = 6.022 X 10^23 The numerical value of the mole is constant, just as the numerical value of dozen is constant.  USE AVOGARDO’S NUMBER TO CONVERT BETWEEN MOLES TO MOLECULES  USE AVOGADRO’S NUMBER TO CONVERT BETWEEN MOLES & ATOMS

MOLES TO PARTICLE CONVERSION

 How many molecules of CuCl

2

are equivalent to 5.79 moles CuCl

2

unit want answer to be in 5.79 mole CuCl 2 x 6.022 x 10 23 molecules CuCl 2 = 3.49 x 10 24 molecule CuCl 2 1mole CuCl 2 unit given in problem Multiply all numbers in numerator , divide by all numbers in denominator. (5.79 mole CuCl 2 )(6.022 x 10^23 molecules CuCl 2 )= 3.49 x 10^24 molecule CuCl 2 1 mole CuCl 2 When dividing, cancel out units

PARTICLE TO MOLE CONVERSION

 What amount in moles is equivalent to 4.24 x 10 25 molecules of C 6 H 12 O 6? 4.24 x 10^25 molecules C 6 H 12 O 6 x 1 mole C 6 H 12 O 6 = 6.022 x 10^23 molecules C 6 H 12 O 6 (4.24 x 10^25 molecules C 6 H 12 O 6 )(1 mole C 6 H 12 O 6 ) = 70.41 moles C 6 H 12 O 6 6.022 x 10^23 molecules C 6 H 12 O 6 Mole is like dozen, it doesn’t matter if you are counting eggs or donuts, dozen is always 12. Doesn’t matter what the chemical is, mole always means 6.022 x 10^23.

You try!

 How many atoms of copper are in 2.5 moles of copper?  A sample of NaCl contains 4.5 x 10 22 molecules. How many moles of NaCl are in the sample?

You try answers!

 How many atoms of copper are in 2.5 moles of copper? 2.5 moles Cu x 6.022 x 10^23 atoms Cu = 1.51 x 10^24 atoms Cu 1 mole Cu  A sample of NaCl contains 4.5 x 10^24 molecules. How many moles of NaCl are in the sample? 4.5 x 1024 molecules NaCl x 1 mole NaCl = 7.5 moles NaCl 6.022 x 10 23 molecules NaCl