Post on 24-Feb-2016
description
How many is that?
kittens21 Couple of
How many is that?
meatballs
121 dozen
How many is that?
pencils1441 gross of
How many is that?
stars1 mole of602,200,000,000,000,000,000,000
1 mole = 602,200,000,000,000,000,000,000
The Mole ?
The Mole ?
The Mole ?
The Mole !
602,200,000,000,000,000,000,0006.022 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10
6.022 x 1023
Avogadro’s Number6.022 x 1023 = “Avogadro’s Number”.
Amadeo Avogadro(1776-1855)
I didn’t discover it. It’s just named after
me!
What’s the mass of … 1 dozen kittens? (1 kitten weighs 3 lbs)
1 dozen 12 kittens 3 lbs 1 dozen 1 kitten
36 lbs
What’s the mass of … 6 dozen meatballs? (1 meatball weighs
35 grams)
6 dozen 12 meatballs35 grams1 dozen 1 meatball
2520 grams
What’s the mass of … 3 gross pencils? (1 pencil
weighs 15 grams)
3 gross 144 pencils 15 grams1 gross 1 pencil
6480 grams
What’s the mass of a mole???
Depends...
If it’s a mole of kittens, we take the mass of one kitten… and multiply by how many kittens.
3 lbs x 6.022 x 1023
If it’s a mole of Carbon atoms, it’s easier than that!
Carbon’s atomic mass = 12.0 grams/mole
SUPER IMPORTANT CONCEPT!
Molar Mass = the mass (in grams) of 1 mole (6.022 x 1023) of anything
Finding the molar mass of an element is pretty easy!• Take it’s atomic mass and make the units
“X grams/1 mole of X atoms”
Try it: Molar mass of Lithium? Helium?
Iron?
6.94 grams/1 mole Li atoms4.00 grams/1 mole He atoms55.85 grams/1 mole Fe atoms
Calculations with Moles:Converting moles to grams
How many grams of lithium are in 3.50 moles of lithium?
3.50 mol Li = g Li1 mol Li6.94 g Li 24.29
Calculations with Moles:Converting grams to moles
How many moles of lithium are in 18.2 grams of lithium?
18.2 g Li = mol Li6.94 g Li1 mol Li 2.62
Calculations with Moles:Using Avogadro’s Number
How many atoms of lithium are in 3.50 moles of lithium?
3.50 mol = atoms
1 mol6.02 x 1023 atoms 2.11 x 1024
Calculations with Moles:Using Avogadro’s Number
How many atoms of lithium are in 18.2 g of lithium?
18.2 g Li
= atoms Li
1 mol Li 6.022 x 1023 atoms Li
1.58 x 1024
6.94 g Li 1 mol Li
(18.2)(6.022 x 1023)/6.94
You try it!If you had 107.92 grams of Aluminum foil, how many moles of Aluminum are there?
= moles Al atoms
You try it!If you had 3.011 x 1023 atoms of Calcium, how many grams of Calcium are there?
= grams Ca
What about for compounds, you ask???
Since a compound is more than one atom bonded, just add the masses of all the atoms there
12.01 g + 2(16.00 g) =44.01 gOne mole of CO2 (6.02 x 1023 molecules) has
a mass of 44.01 grams
Example: Carbon Dioxide (CO2)
You try it!1 mole of NaCl would weigh exactly how many grams?
= grams NaCl
6 moles of NaCl would weigh exactly how many grams?
= grams NaCl
You try it!How many grams of Dihydrogen Monoxide are in 6.022 x 1023 molecules of Dihydrogen Monoxide?
= grams H2O
Standard Molar VolumeEqual volumes of all gases at the same temperature and pressure contain the same number of molecules.
- Amedeo Avogadro
At STP (Standard Temperature and Pressure):Standard Temperature = 0˚ C
Standard Pressure = 1 atmosphere
1 mole of a gas occupies 22.4 liters of volume
Calculations with Moles:Using Standard Molar Volume
How many moles of hydrogen are in 100 L of hydrogen at STP?
100 L = mol22.4 L
1 mol 4.46
Calculations with Moles:Using Standard Molar Volume
How many liters are occupied by 3 moles of oxygen gas at STP?
3 mol = L 1 mol
22.4 L 67.2
You try it!16 moles of Cl2 gas would occupy how many liters?
= L Cl2
= grams Cl2
16 moles of Cl2 gas would have a mass of how many grams?
Do it all at once!35 grams of carbon tetrafluoride gas would occupy how many liters?
1 mol CF4 = L CF41 mol22.4 L
8.988.01 g
35 g
You try it!1373 grams of N2 gas would occupy how many liters?
…………………………………………………..= L N2
Mole Relationship
s
Mole
Atomsor
molecules
Liters
Grams
6.02 x 10 23
Atom
icM
ass
22. 4
L22.4 L