Determination of the solubilityproduct constant for a 恒为溶度积测定
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Experiment 27 March 9, 2019 Dr. Scott Buzby, Ph.D.
Determination of the solubility-product constant for a sparingly soluble salt
Objectives
Learn to experimentally determine the solubility constant ation Curve
Prepare a series of solutions of a known concentration
Plot absorbance vs. concentration for the known solutions
By measuring absorbance of an unknown sample you can determine concentration using your plot (follow red arrows on graph)
Next Class (3/23/2019)
Report Sheet – Pgs. 315-316 Questions – Pgs. 316-317 Calibration Graph – Pg. 318 or print-out Pre-Lab Experiment 28 – Pg. 323
using your calibration graph Calculate silver concentration, [Ag+], and Ksp for
you solution (see notes on page 313)
For Next Class
Next Week – Nothing Enjoy Spring Break!
The solubility of silver carbonate is expressed by the equation:
Ag2CO3(s) 2Ag(a2q) CO3(2aq)
Kc
[ Ag2 ]2[CO32 ] [ Ag2CO3]
Ksp [ Ag2 ]2[CO32 ]
spectrophotometer
Procedure on page 311
Determination of Ksp
FOLLOW ALL INSTRUCTIONS PRECISELY!!! Prepare three separate solutions according to
the procedure on page 312 Determine the chromate concentration, [CrO42-],
Beer-Lambert Law
A abc
Ac
Beer-Lambert Law
Aabc
A – Absorbance of the solution a – Molar absorption coefficient (constant) b – Path length (constant) c - Concentration
Practice operation of a spectrophotometer
Further explore the use of a calibration graph and Beer-Lambert Law
solubility constant (Ksp)
For a true equilibrium to exist between a solid and a solution, the solution must be saturated (i.e. solid material must remain at the bottom of the solution)
We will use a spectrophotometer to determine the intensity of the color of a solution
Described on pages 310 & 312 in you text Absorbance is related to concentration by the
Determination of the solubility-product constant for a sparingly soluble salt
Objectives
Learn to experimentally determine the solubility constant ation Curve
Prepare a series of solutions of a known concentration
Plot absorbance vs. concentration for the known solutions
By measuring absorbance of an unknown sample you can determine concentration using your plot (follow red arrows on graph)
Next Class (3/23/2019)
Report Sheet – Pgs. 315-316 Questions – Pgs. 316-317 Calibration Graph – Pg. 318 or print-out Pre-Lab Experiment 28 – Pg. 323
using your calibration graph Calculate silver concentration, [Ag+], and Ksp for
you solution (see notes on page 313)
For Next Class
Next Week – Nothing Enjoy Spring Break!
The solubility of silver carbonate is expressed by the equation:
Ag2CO3(s) 2Ag(a2q) CO3(2aq)
Kc
[ Ag2 ]2[CO32 ] [ Ag2CO3]
Ksp [ Ag2 ]2[CO32 ]
spectrophotometer
Procedure on page 311
Determination of Ksp
FOLLOW ALL INSTRUCTIONS PRECISELY!!! Prepare three separate solutions according to
the procedure on page 312 Determine the chromate concentration, [CrO42-],
Beer-Lambert Law
A abc
Ac
Beer-Lambert Law
Aabc
A – Absorbance of the solution a – Molar absorption coefficient (constant) b – Path length (constant) c - Concentration
Practice operation of a spectrophotometer
Further explore the use of a calibration graph and Beer-Lambert Law
solubility constant (Ksp)
For a true equilibrium to exist between a solid and a solution, the solution must be saturated (i.e. solid material must remain at the bottom of the solution)
We will use a spectrophotometer to determine the intensity of the color of a solution
Described on pages 310 & 312 in you text Absorbance is related to concentration by the