STOICHIOMETRY OF CHEMICAL REACTION.
Objectives: after you have studied this topic, you should be able among others to:
● Use chemical formulas to solve various kinds of chemical problems
● Identity and use formulary weights and mole relationships.
● Interconvert masses, moles and formulas
● Determine formula from composition
● Perform calculations of purity of substances
● Interpret balanced chemical equations to calculate the moles of reactants and
products involved in each of the reactions.
● Determine which reactant is the limiting reactants in reactant in reactions.
● Compare the amount of substance actually formed in a reaction(actual yield) with the
predicted amount (theoretical yield) and determine the percentage yield.
● Work and follow sequential reactions
● Use the terminology of solutions -solute, solvent and concentration
● Calculate concentrations of solution when they are diluted
● Carryout calculations related to the use of solutions in Chemical Reactions
● Perform molarity calculations
● Solve acid-base stoichiometry calculations
● Describe titration and standardization
● Use the mole methods and molarity in acid-base titration reactions.
The Word “Stoichiometry is derived from the Greek word stoicheion, which means measure.
Stoichiometry describes the quantitative relationships among elements in compound
(composition Stoichiometry) and among substances as they undergo chemical changes
(reaction Stoichiometry).
THE MOLES CONCEPT
Moles is defined as the amount of substances that contains as many entities (atoms,
molecules, ion or other particles) as there are atoms in exactly 12.00g of pure carbon-12
atoms i.e 1 mole=6.02*10^23.
,The mole concept, together with Avogadro number, provides important relationships among
the extensive properties! Mass, volume, number of moles, atoms, molecules, ions of any
given substance.
Composition Stoichiometry
Moles
● How many moles of atoms does 136.9g of iron metal contain?(Fe=55.85g mol)
Solution
I mole of Fe atoms=55.85g
X mole of Fe atoms=136.9g
X=1×136.9/55.85
X=2.451mole Fe atoms.
● How many moles of oxygen (O2), Oxygen (O2) molecules, Oxygen gas(dioxygen) at
25 degree centigrade
(0=16)
solution
.The mass of one mole of Oxygen is 32.0g(molar mass of oxygen=32g/mol)
i.e 1 mole of oxygen=32.0g
X mole of Oxygen=40.0g
X= 1×40÷32= 1.25mole of Oxygen.
1mol of Oxygen contains 6.02×20^23 molecules
Objectives: after you have studied this topic, you should be able among others to:
● Use chemical formulas to solve various kinds of chemical problems
● Identity and use formulary weights and mole relationships.
● Interconvert masses, moles and formulas
● Determine formula from composition
● Perform calculations of purity of substances
● Interpret balanced chemical equations to calculate the moles of reactants and
products involved in each of the reactions.
● Determine which reactant is the limiting reactants in reactant in reactions.
● Compare the amount of substance actually formed in a reaction(actual yield) with the
predicted amount (theoretical yield) and determine the percentage yield.
● Work and follow sequential reactions
● Use the terminology of solutions -solute, solvent and concentration
● Calculate concentrations of solution when they are diluted
● Carryout calculations related to the use of solutions in Chemical Reactions
● Perform molarity calculations
● Solve acid-base stoichiometry calculations
● Describe titration and standardization
● Use the mole methods and molarity in acid-base titration reactions.
The Word “Stoichiometry is derived from the Greek word stoicheion, which means measure.
Stoichiometry describes the quantitative relationships among elements in compound
(composition Stoichiometry) and among substances as they undergo chemical changes
(reaction Stoichiometry).
THE MOLES CONCEPT
Moles is defined as the amount of substances that contains as many entities (atoms,
molecules, ion or other particles) as there are atoms in exactly 12.00g of pure carbon-12
atoms i.e 1 mole=6.02*10^23.
,The mole concept, together with Avogadro number, provides important relationships among
the extensive properties! Mass, volume, number of moles, atoms, molecules, ions of any
given substance.
Composition Stoichiometry
Moles
● How many moles of atoms does 136.9g of iron metal contain?(Fe=55.85g mol)
Solution
I mole of Fe atoms=55.85g
X mole of Fe atoms=136.9g
X=1×136.9/55.85
X=2.451mole Fe atoms.
● How many moles of oxygen (O2), Oxygen (O2) molecules, Oxygen gas(dioxygen) at
25 degree centigrade
(0=16)
solution
.The mass of one mole of Oxygen is 32.0g(molar mass of oxygen=32g/mol)
i.e 1 mole of oxygen=32.0g
X mole of Oxygen=40.0g
X= 1×40÷32= 1.25mole of Oxygen.
1mol of Oxygen contains 6.02×20^23 molecules
