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Chemistry 103/113 Laboratory |
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This Week |
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Expt 8:
Stoichiometry by Spectrophotometry o NOT EXPT 4 o Quiz 2: Expt 2, Study Assignment C |
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Next Time (After Fall Break) |
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o Preliminary Assignment due o
Quiz
3: Expt 3, Study Assignment E |
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Notes for Today |
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Problem: What is the stoichiometry for rxn of
Fe2+ with a ligand molecule (L)? Fe2+(aq)
+ xL(aq)
-> Fe(L)x2+(aq) ·
Strategy o
Vary Fe2+: L mole ratio o
Measure absorbance
of reaction mixture to monitor reaction progress A ·
Questions to
consider oHow does the amount of
Fe(L)x2+ produced depend on moles of reactants used? oHow will you know which reactant is limiting? In excess? oHow will you know if the reaction is incomplete? ·
Tasks for today o
Prepare rxn mixture
with precisely known Fe2+, L
concentrations o
Measure absorbance
of rxn mixture o
Plot class
stoichiometry data using Excel ·
New equipment in
this experiment o
Pipet and pipet pump
for volume measurements to +/-0.01 mL
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Volumetric flask
for preparing solution of precisely known volume o
Spectrophotometer
to measure light absorbance
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Safety
Issues o
Goggles required
when preparing solutions. o
Exercise caution
with glass pipets §
Gently insert end
of pipet into pump. Never use force. §
Hold pipet
securely, never by the pump. |
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