Transcript Take your periodic table out

Take your periodic table out
What is atomic mass of Carbon
Point where you can find it in the
periodic table!
6 is atomic number not
atomic mass
Atomic mass= mass of 1 mol
Calculating
Formula Mass /molecular weight
Write down how you calculate the formula mass of
carbon dioxide, CO2.
12.01 g + 2(16.00 g) =
 One mole of CO2 (6.02 x 1023 molecules) has a mass
of 44.01 grams
We use Unit factors = ratio of 1:1 to convert
1 mole= 6.022 X 10 ^ 23 atoms
1 mole= atomic mass if an atom( like C)
Molecular weight if a molecule (CO2)
• Why are Ratio of 1 significant?
3.09X10^23 atoms= ?mol
Math rule: If we multiply something on one side
we have to do it on the other side
Ratio of 1 so we don’t need to worry about that
rule
Calculations with Moles:
Converting moles to grams
How many grams of lithium are in 3.50 moles of
lithium?
3.5moles-> ? g lithium
3.50 mol Li
6.94 g Li
1 mol Li
What unit factor are we using here?
1 mole= 6.94g Li
= 24.3 g Li
Calculations with Moles:
Using Avogadro’s Number
How many atoms of lithium are in 3.50 moles of
lithium?
3.50 mol
6.02 x 1023 atoms
1 mol
What unit factor are we using here?
1 mole= 6.022 X 10 ^ 23 atoms
= 2.11 x 1024 atoms
Calculations with Moles:
Converting grams to moles
How many moles of lithium are in 18.2 grams of
lithium?
18.2 g Li
1 mol Li
6.94 g Li
What unit factor are we using here?
1 mole= 6.94g Li
= 2.62 mol Li
Calculations with Moles:
Using Avogadro’s Number
How many atoms of lithium are in 18.2 g of
lithium?
18.2 g Li
1 mol Li
6.022 x 1023 atoms Li
6.94 g Li
(18.2)(6.022 x
1023)/6.94
1 mol Li
24
1.58
x
10
=
What unit factors are we using here?
6.941 g 1 =mole
1 mole= 6.022 X 10 ^ 23 atoms
atoms Li