1. Intro to Stoichiometry & the Mole

2. Particles = atoms, molecules, peas or baseballs!
The Mole:
Substances are composed of particles.
To measure specific amounts, we must count the # of particles
BUT atoms, ions and molecules are soooo small, counting each one would be impossible!
Therefore we use a term to represent a certain amount of particles:
1 MOLE = 6.02 x 1023 particles
Particles = atoms, molecules, peas or baseballs!
6.02 x 1023 is Avogadro’s number

3. Ex. How many atoms are in 1 mole of Mg? 6.02 x 1023 atoms
How many molecules are in 1 mole of CO2?
6.02 x 1023 molecules

4. MOLAR MASS: Ex. KI = (39.09 + 126.91)= 166.00 g/mol
The mass of a molecule or element measured in grams/mole.
Ex. KI = ( )= g/mol
Ex. O2 = (2 x 16.00) = g/mol
Ex. He = 4.00 g/mol

5. What is the mass of 5 moles of He atoms?
What is the mass of 3 moles of NaCl?
x = 20.0 g
Write one example!
x = g

6. How many moles of silver are in 9.5 x 102g?
How many moles of MnO2 are in 35.0g?
x = 8.8 mol of Ag
Write this!
x = mol of MnO2

7. Advogadro’s # tells us that: 1 mol = 6.02 x 1023 atoms/molecules
Write this!
Advogadro’s # tells us that: 1 mol = 6.02 x 1023 atoms/molecules
How many atoms are in 3 moles of He?
x = 1.81 x 1024 atoms

8. Write this!
Stoichiometry:
Is the use of proportions, from a balanced chemical equation, to determine the quantity of substances involved in a chemical reaction.
Chemical equations show the proportional relationships among the products & reactants

9. Calculate: 25.0 moles How many moles of C are in 300g?
How many moles of NaOH are in 160g?
What is the mass of 6 moles of CaCl2?
How many molecules are present in 1.258x10-5g of NaCl?
How many molecules are present in a g sample of H2 gas?
4.00 moles
665.88g
1.30 x 1017 molecules
9 x 1020 molecules

10. Ex.1 2Mg + O2 → 2MgO
2 : 1 : 2
Mole Ratio – describes the ratio in which the substances combine/form
If one wishes to produce 4 moles of MgO, then
4 moles of Mg are needed, &
2 moles of O2 are needed.
If 0.5 moles of O2 are available then
1 mole of Mg is needed, &
1 mole of MgO will be produced

11. Ex.1
How many moles of nitrogen gas & hydrogen gas are required to make 7.24 mol of ammonia?
N2 (g) + 3H2(g) → 2NH3(g)
3.62 mol of N2 are needed
& 10.9 mol of H2 are needed.

12. Ex.2a
How many moles of Lithium are needed to react with fluorine gas to make 435g of lithium fluoride?
2 Li + F2 → 2 LiF
x = moles of LiF were made
2:2 ratio, means the same # moles for Li & LiF
16.8 moles of Li are required

13. You can use a gram ratio to use 1 step to go from 435g LiF to 116g Li
Ex.2b
How many grams of Lithium are needed?
You can use a gram ratio to use 1 step to go from 435g LiF to 116g Li
2 Li F2 → 2 LiF
Gram ratio (2 x 6.94) : (19.00 x 2) : (2 x 25.94) g of Li : g of F2 : g of LiF
x = 116g of Li.
x = 116g of Li.

14. Write this!
Ex.3
How many grams of NaClO3 must be decomposed to produce NaCl & 52.8 g of oxygen gas?
2NaClO3 → NaCl O2
Gram ratio ( x 2) : : (32.00 x 3)
212.88g : : g
117g NaClO3

15. Sheet – due next class
Typo!!!!!! #5b 7.75g of P4 #5d P4