II. Stoichiometry in the Real World Stoichiometry – Unit. 10.
I. I.Stoichiometric Calculations Stoichiometry. History of Stoichiometry b Comes from the Greek:...
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Transcript of I. I.Stoichiometric Calculations Stoichiometry. History of Stoichiometry b Comes from the Greek:...
I. Stoichiometric
Calculations
I. Stoichiometric
Calculations
StoichiometryStoichiometry
History of StoichiometryHistory of StoichiometryHistory of StoichiometryHistory of Stoichiometry
Comes from the Greek:
Stoicheion
- to measure the elements
History of StoichiometryHistory of StoichiometryHistory of StoichiometryHistory of Stoichiometry
Joseph Black and Daniel Rutherford
studied the reaction
CaCO3 CaO + CO2
They were looking at how the mass was changing in the reaction. They realized there the relation in the changing mass was actually in moles of substance.
Proportional Proportional RelationshipsRelationshipsProportional Proportional RelationshipsRelationships
StoichiometryStoichiometry• mass relationships between
substances in a chemical reaction• based on the mole ratio
Mole RatioMole Ratio• indicated by coefficients in a
balanced equation
2 Mg + O2 Mg + O22 2 MgO 2 MgO
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas?
9 mol O2 2 mol KClO3
3 mol O2
= 6 mol KClO3
2KClO3 2KCl + 3O2 ? mol 9 mol
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
How many moles of KCl are produced when 3.6 mol of KCLO3 are decomposed?
3.6 mol KClO3
2 mol KCl2 mol KClO3
= 7.2 mol KCl
2KClO3 2KCl + 3O2 ? mol3.6 mol
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
Do Mole to Mole WS
Stoichiometry StepsStoichiometry Steps Stoichiometry StepsStoichiometry Steps
1. Write a balanced equation.2. Identify known & unknown.3. Line up conversion factors.
• Mole ratio - moles moles• Molar mass - moles grams• Molarity - moles liters soln• Molar volume - moles liters gas
Core step in all stoichiometry problems!!
• Mole ratio - moles moles
4. Check answer.
1 mol of a gas=22.4 Lat STP
Molar Volume at STPMolar Volume at STP Molar Volume at STPMolar Volume at STP
Standard Temperature & Pressure0°C and 1 atm
““Stoich – nid”Stoich – nid”““Stoich – nid”Stoich – nid”
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
How many grams of silver will be formed when 12.0 g copper react with excess
aqueous silver nitrate?
12.0g Cu
1 molCu
63.55g Cu
= 40.7 g Ag
Cu + 2AgNO3 2Ag + Cu(NO3)2
2 molAg
1 molCu
107.87g Ag
1 molAg
12.0 g ? g
63.55g Cu
1 molCu
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
How many grams of Copper atoms are required to react completely with 1.5 x 1023 formula units of AgNO3?
1.5 x 1023
Form units AgNO3
1molAgNO3
6.022 x 1023
Form units AgNO3
= 7.9 g Cu
Cu + 2AgNO3 2Ag + Cu(NO3)2
1 mol Cu
2 molAgNO3
? g 1.5 x 1023
form units
How many grams of KClO3 are req’d to
produce 9.00 L of O2 at STP?
9.00 LO2
1 molO2
22.4 L O2
= 32.8 g KClO3
2 molKClO3
3 molO2
122.55g KClO3
1 molKClO3
? g 9.00 L
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
2KClO3 2KCl + 3O2
Stoichiometry ProblemsStoichiometry ProblemsStoichiometry ProblemsStoichiometry Problems
Do Stoich WS 1