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Chemistry Lab Exam

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Light Source function
Provides radiant energy
Entrance Slit function
Provides a narrow beam of incoming light
Diffracting Grating function
allows single beam of light to be focused on one segment of visible spectrum
Exit Slit function
Focuses spectral segment on sample
Wavelength Selector
Moves the entrance slit across the colors of the spectrum provided by the Diffraction Grating
Sample Holder (Cuvette Holder)
Holds solution in Optical pathway
Photodetector
Converts radiant energy into electrical energy
Signal Processor
Modifies radiant energy to drive analog meter
Ways to calibrate a micropipette
using a balance to make sure that one ml is being delivered; 1mL=1g
Classes of water and their functions
Type 1: deionized water: results from ion exchange purification
Type 2: Double Distilled water: acceptable in most Clinical Labs; collected by boiling water and collecting the condensation
Type 3: used for washing dishes in lab
Ionic Strength
the combination of positive and negative charges of the ions in a solution
Colligative Properties
"Binding or fastening properties" examples: Vapor pressure, boiling point, freezing point, osmotic pressure
Standard
Have a single known concentration of a substance used to set up "Standard Curves"
Controls
Used to calibrate equipment and get measurements to fall in a certain range
RCF formulae
1.118 x 10^-5 x r x speed ^2

r= distance in cm from center to middle of 2nd row cuvette holder
How many Centimeters in an inch
2.54 cm
One point equation
Concentration (unknown)=[Absorbance (unknown)/Absorbance (standard)] x Concentration (standard)
Define Spectrophotometer
an instrument that measures monochromatic light
"0" adjuster knob function
used to compensate for background noise entering the cuvette well
What is measured in a spectrophotometer
Transmitted light
Beer's Law
A=abc

A=absorbance a=molar absorptivity b=distance traveled by light c=concentration
Purpose of Standards Curve
to compare the absorbance of unknowns to the absorbance of standard solutions
Safety diamond
Red= flammability Blue= Health Hazards
Yellow= Reactivity White= Specific hazards (specials)