Lab 12: Iron Content Analysis
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Transcript Lab 12: Iron Content Analysis
Due Today:
1 . Iron Content
Analysis PreLab
IRON CONTENT
ANALYSIS
2. Neutralizing
Power of
Antacids Formal
Lab Report
Homework:
1. Iron Content
Analysis Short
Report
2. Prepare for
Laboratory Final
OBJECTIVE
Introduction to ultraviolet-visible
(UV-Vis) spectroscopy
Introduction to analytical chemistry
Determine the iron content in vitamin
tablets
KEY TERMS
Visible Range: 700-400 nm
UV Range: 10-400 nm
KEY TERMS
Spectroscopy – measuring the interaction
of radiation with matter
Unique wavelength for each substance
Scanning – determine wavelength with maximum
absorption
Chemists are most interested in the
electromagnetic spectrum between 190-900 nm
KEY TERMS
Beer-Lambert Law - Absorbance of a solution
is linearly related to concentration and
identity of the chemical in solution
𝐴 = 𝑏𝑐
A: absorbance
b: extinction coefficient
c: concentration
PROCEDURE NOTES
Use Volumetric Glassware
Volumetric flask
Graduated pipets
Burets
Use stock solutions dispensed from burets
PROCEDURE NOTES
Wipe off the cuvette with a Kim-Wipe before
inserting into the Spectrophotometer
Record the absorbances!
Record the advertised Iron content from
both vitamin bottles!
WASTE
Solutions can be disposed of down the
drain
RISK ASSESSMENT
Hydrochloric Acid
Danger
Inhalation Hazard
Corrosive
RISK ASSESSMENT
Hydroquinone
Danger
Harmful if Swallowed
Skin Irritant
RISK ASSESSMENT
o-phenanthroline
Danger
Toxic if swallowed
CALCULATIONS
𝑀1 𝑉1 = 𝑀2 𝑉2
Molarity units: mg of Fe/100 mL
[Stock solution]= 40 mg/L=4 mg/100mL
V 1= volume of stock iron solution in each trial
V 2=100 mL (total volume)
CALCULATIONS
Graphing in Excel
Force the trendline through (0,0)
Include the equation of the tendline and R 2 value
Y = mx
A = bc