140 likes | 518 Views
“Mole…mole…mole…”. Not the kind on your face…. What you know…. What an atomic mass unit ( amu ) is What the formula mass of a given molecule is How to convert from atoms to amu With elements With compounds . Objectives. SWBAT define a mole .
E N D
“Mole…mole…mole…” Not the kind on your face…
What you know… • What an atomic mass unit (amu) is • What the formula mass of a given molecule is • How to convert from atoms to amu • With elements • With compounds
Objectives • SWBAT define a mole. • SWBAT convert from moles to atoms/molecules using Avogadro’s number • SWBAT recall that subscripts equal the number of molecules in a molecular formula
What is a mole? • Any of various small insectivorous mammals, esp. of the family Talpidae, living chiefly underground, and having velvety fur, very small eyes, and strong forefeet.
Really…what is a mole? • A spy who becomes part of and works from within the ranks of an enemy governmental staff or intelligence agency.
Ok, seriously, what is a mole? • A unit measuring the amount of a substance. • This unit measures the physical quantities • 1 mole of sodium = 1 mole of gold
Moles are all equal to one thing. • 1 mole is always equal to 6.02 x 1023 molecules or atoms. • Say it with me “6 point O two times 10 to the 23rd” • This is your conversion factor when you are dealing with moles to atoms of molecules.
What does that mean? • Well, it means that when you are going from moles (mol) are always going to be equal to 6.02 x 1023 molecules. • Its like saying there are a dozen eggs of a dozen donuts… • How many donuts is that? How many eggs? • It’s always 12 right? • In the same way, a mole is always 6.02 x 1023 molecules no matter what element you are talking about.
How do you know how many moles there are? • The subscripts!!! • Subscripts tell you a good amount about an atom • It tells you how many atoms are in a molecule (remember yesterday with formula mass) • It ALSO tells you the amount of moles of each atom are in 1 mole of a compound • Say WHAT?!?! • That doesn’t make too much sense so let’s try to dissect that
What does the subscript mean? • If we had the formula of aspirin (C9H8O4) it would tell us that… • We have 9 atoms of C, 8 atoms of H, and 4 atoms of O • We also know that it has 9 moles of C, 8 moles of H, and 4 moles of O • How does that work out? • “If there are 6.02 x 1023 molecules (1 mol) of NH3, it would contain 6.02 x 1023 atoms (1 mol) N and 3 x 6.02 x 1023 atoms (3 mols) H. Thus each subscript in a formula also refers to the moles of each kind of atom”
What do I really need to know? • That the subscripts will tell you BOTH • How many atoms a compound has • How many moles of atoms in the mole of a compound • This is called a mole to mole ratio
How do you use that information? • How many moles of carbon atoms are present in 1.50 mol aspirin, C9H8O4? • Given: 1.50 mol C9H8O4 Want: mols of C atoms 1.50 mol C9H8O4 9 mol C atoms 13.5 mols C atoms 1 mol C9H8O4