stoichiometry
DESCRIPTION
Stoichiometry. Stoichiometry. Is the study of the relative quantities of reactants and products in chemical reactions the mole ratio. How can you get to the moon?. You need ROCKET FUEL!. 2N 2 H 4 (l) + N 2 O 4 (l) 3N 2 (g) + 4H 2 O(g) + ENERGY - PowerPoint PPT PresentationTRANSCRIPT
Stoichiometry
Stoichiometry
•Is the study of the relative quantities of reactants and products in chemical reactions
the mole ratio
How can you get to the moon?
You need ROCKET FUEL!
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
(hydrazine) (dinitrogen tetroxide)
If 1000 tonnes of N2O4 is to be used, how much N2H4 should be used?
Ratios in Balanced Chemical Equations
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
This equation means:
2 molecules of N2H4 react with 1 molecules of N2O4
• 200 molecules of N2H4 react with ______ molecules of N2O4100
• 4 molecules of N2H4 react with ______ molecules of N2O42
• 16 million molecules of N2H4 react with _________ molecules of N2O48 million
OR 2 moles of N2H4 react with 1 mole of N2O4
• The reactants and products in a balance chemical equation will always be related by ratios established by the coefficients in the equation.
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
a.) How many moles of N2H4 are required to react with 8 moles of N2O4?
2 mols of N2H4 = x mols of N2H4 1 mols of N2O4 8 mols of N2O4
x mols of N2H4 X 1 mols of N2O4 = 2 mols of N2H4 X 8 mols ofN2O4
Cross multiply!
x mols of N2H4 = 16 mols of N2H4
x mols of N2H4 = 2 mols of N2H4 X 8 mols ofN2O4
1 mols of N2O4
Step 1: Check the equation is balanced
Step 2: Set up mole ratio 2 mols of N2H4
1 mols of N2O4
Step 3: set equal to given and unknown
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
b.) How many moles of N2H4 are required to react with 17 moles of N2O4?
x mols of N2H4 = 2 mols of N2H4 17 mols of N2O4 1 mols of N2O4
x mols of N2H4 = 2 mols of N2H4 X 17 mols of N2O4
1 mols of N2O4
= 34 mols of N2H4
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
c.) How many moles of N2H4 are required to react with 0.23 moles of N2O4?
x mols of N2H4 = 2 mols of N2H4 0.23 mols of N2O4 1 mols of N2O4
x mols of N2H4 = 2 mols of N2H4 X 0.23 mols of N2O4
1 mols of N2O4
= 0.46 mols of N2H4
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
d.) How many moles of H2O are produced from 8 moles of N2H4?
x mols of H2O = 4 mols of H2O
8 mols of N2H4 2 mols of N2H4
x mols of H2O = 4 mols of H2O X 8 mols of N2H4
2 mols of N2H4
= 16 mols of H2O
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
e.) How many moles of N2 are produced from 11 moles of N2O4?
x mols of N2 = 3 mols of N2
11 mols of N2O4 1 mols of N2O4
x mols of N2 = 3 mols of N2 X 11 mols of N2O4
1 mols of N2O4
= 33 mols of N2
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
f.) If 0.55 moles of H2O are produced, How much N2H4 reacted?
x mols of N2H4 = 2 mols of N2H4
0.55 mols of H2O 4 mols of H2O
x mols of N2H4 = 2 mols of N2H4 X 0.55 mols of H2O
4 mols of H2O
= 0.28 mols of N2H4
2N2H4 (l) + N2O4 (l) 3N2(g) + 4H2O(g) + ENERGY
g.) If 0.55 moles of H2O are produced, How much N2 is produced?
x mols of N2 = 3 mols of N2
0.55 mols of H2O 4 mols of H2O
x mols of N2 = 3 mols of N2 X 0.55 mols of H2O
4 mols of H2O
= 0.41 mols of N2
Phosphorus can be combined with oxygen gas to form diphosphorus trioxide. How many molecules of diphosphorus trioxide can be made from 5 moles of phosphorus?
• Write out balanced chemical equation
4P(s) + 3O2(g) 2P2O3(s)
x mols of P2O3 = 2 mols of P2O3
5 mols of P 4 mols of P
x mols of P2O3 = 2 mols of P2O3 X 5 mols of P
4 mols of P
= 2.5 mols of P2O3
Molecules of P2O3 = 2.5 mols of P2O3 X 6.022 X 1023 molecules/mols of P2O3
= 1.5 x 1024 molecules of P2O3
Assignment : Practice Problems pages 237-238 #1-7, page 240 #9, 10