Notes and Preparation for Chem 124 Labs Spring 2009
01 Vapor Pressure as a Function of Temperature
02 Freezing Point Depression
03 Rate Law of a Chemical Reaction
04 Activation Energy of a Chemical Reaction
05 Equilibrium of the Iron Thiocyanante Reaction
06 Ksp of CaSO4 (Ca(OH)2 could be substituted for this experiment)
07 Salt Hydrolysis
08 Buffer Solutions
09 Titration of an Unknown Organic Acid
10 Thermodynamics of Borax Solubility
11 Measuring Electrochemical Cells
Vapor Pressure as a Function of Temperature
Reagents:
1.
2.
3.
Equipment:
1.
2.
3.
4.
4 x 250 mL Acetone
4 x Boiling chips
Ice
Vacuum distillation set-up
Hot Plate
1000 mL beaker
Small thermometer
Student set-up:
In the hood the vacuum distillation apparatus should be pre assembled.
The arrangement can be designed that groups of three students collect a set
of boiling point vs vapor pressure data for an organic liquid. Data
collection take about 1 hr. Student groups can rotate through once and
hour.
Preparation:
Waste:
Vapor traps should be collected and the used organic liquid can be
redistilled for reuse. Otherwise all liquids should be considered nonhalogenated organic waste.
Freezing Point Depression
Reagents:
1. 3 x 500 mL t-butylalcohol
2. 12 x 2 g. Mandelic acid (label small vial as unknown solid)
3. Ice
Equipment:
1.
2.
3.
4.
12 Football stir bars
12 Stir motors
12 Digital thermometers
12 Ring stands and clamps for thermometers
Student set-up:
Students work in pairs and measure the freezing point of TBA with
varying amounts of unknown solid in the TBA solvent.
Preparation:
Waste:
All TBA waste should be disposed will have approximately 5% mandelic
acid and should be disposed of as non-halogenated organic waste.
Rate Law of a Chemical Reaction
Reagents:
1. 3 x 1000 mL of 4 M Acetone(aq)
2. 3 x 500 mL 0.005 M I2(aq)
3. 3 x 1000 mL 1.0 M HCl
Equipment:
1. 12 x stopwatches
2. 12 x 10 mL pipets
3. 12 x 5 mL pipets
4. 12 x pipet bulbs
Student set-up:
Reactions are run in Erlynmyer flasks from student drawers
Preparation:
1. 3 x 1000 mL of 4 M Acetone(aq)
(Prepare by mixing 300 mL acetone upto 1L of H2O)
2. 3 x 500 mL 0.005 M I2(aq)
(Prepare by dissolving 1.3 g I2 and 4g KI in 50 mL H2O
dissolve to 1 liter H2O. Allow to stir overnight.)
3. 3 x 1000 mL 1.0 M HCl
(Prepare by mixing 83 mL conc. HCl upto 1000 mL H2O.)
Waste:
Activation Energy of a Chemical Reaction
Reagents:
1. 3 x 1000 mL of 4 M Acetone(aq)
2. 3 x 500 mL 0.005 M I2(aq)
3. 3 x 1000 mL 1.0 M HCl
Equipment:
1. 12 x stopwatches
2. 6 x hot plates
3. 12 x1000 mL beakers
4. 12 x ring stands
5. 12 x 15 mL testtubes
6. 12 x Ethanol thermometers
Student set-up:
Reactions are run in Erlynmyer flasks from student drawers
Preparation:
1. 3 x 1000 mL of 4 M Acetone(aq)
(Prepare by mixing 300 mL acetone upto 1L of H2O)
2. 3 x 500 mL 0.005 M I2(aq)
(Prepare by dissolving 1.3 g I2 and 4g KI in 50 mL H2O
dissolve to 1 liter H2O. Allow to stir overnight.)
3. 3 x 1000 mL 1.0 M HCl
(Prepare by mixing 83 mL conc. HCl upto 1000 mL H2O.)
Waste:
Equilibrium of the Iron Thiocyanante Reaction
Reagents:
1. 3 x 250 mL 0.002 M Fe(NO3)3 in 1 M HNO3(aq)
2. 3 x 250 mL 0.002 M KSCN
Equipment:
1. 6 x spectronic 20
2. 24 x spectroscopy cuvets
3.
Student set-up:
Preparation:
1. 1L of 0.002 M Fe(NO3)3 is made by dissolving 0.81 g
Fe(NO3)39H2O in 1000 mL of 1.0 M HNO3(aq).
2. 1 M HNO3 is prepared by dissolving 66 mL of conc. HNO3
upto 1 L of H2O.
3. 1 L of 0.002 M KSCN is made by dissolving 0.194 g KSCN in
1000 mL H2O.
Waste:
Ksp of CaSO4
Reagents:
1.
2.
3.
4.
3 x 250 mL 1.0 M HCl(aq)
3 x 500 mL 0.01 M NaOH (standardized)
4 x 1000 mL saturated CaSO4(aq) solution
6 x dropper bottle of phenophthalein
Equipment:
12 x Dowex packed column
12 x Ring stand and clamp
Student set-up:
Preparation:
Waste:
Titrated solutions are of neutral pH. Excess strong acids and bases
should be collected and neutralized.
Salt Hydrolysis
Reagents:
1. 6 x dropper bottles universal indicator
2. 3 x 100 g NH4NO3 (s)
3. 3 x 100 g NaHCO3(s)
4. 1 x 50 g NaHSO4(s)
5. 1 x 50 g NaH2PO4(s)
6. 1 x 50 g Na2CO3(s)
Equipment:
1. 12 x 100 mL volumetic flask
Student set-up:
Preparation:
Waste:
Buffer Solutions
Reagents:
1. 6 x dropper bottles universal indicator
2. 3 x 50 g NaH2PO4
3. 3 x 50 g K2HPO4
4. 3 x 1000 mL 0.1 M NaOH
5. 3 x 1000 mL 0.1 M NaOH
6. 3 x 50 g NaCH3CO23H2O
Equipment:
1. 24 x burets
2. 12 x ring stand and buret clamp
Student set-up:
At the front of the room a buret containing very dilute 0.0001 M NaOH
should be available to make the pH of our water close to pH = 7. The
concentration of this dilute solution does not matter.
Preparation:
Waste:
Titration of an Unknown Organic Acid
Reagents:
1. (14 x 1.2 g vials ) Mandelic acid (labeled with an unknown #s)
2. (3 x 5 g) Oven dried potassium hydrogen phthalate (KHP) in small
reagent containers. Should be stored in a dessicator between labs
3. (6 x dropper bottle) phenolphthalein indicator
4. (3 x 50 mL) 6 M NaOH(aq) in plastic 200 ml reagent bottles
Equipment:
1. 12 500 mL plastic nalgene bottles with screw cap (these are to hold
student NaOH)
2. 12 burets (one per student group)
3. At least two pH meters at the front of the room. The meters should
have pH 7 and pH 4 standards.
Student set-up:
Students work in groups of two.
An unknown organic acid (mandelic acid) is titrated with standardized
NaOH.
At the front of the room unknown vials of 1.0 – 1.2 g of mandelic acid are
available for each student group.
Three reagent stations containing: KHP, and two dropper bottles of
phenolphthalein.
Preparation:
No solution preparation is required.
Waste:
All titrated samples are collected in a waste beaker.
Thermodynamics of Borax Solubility
Reagents:
3 x 500 g Borax (from grocery store)
3 x 1000 mL 0.2 M HCl standarized
6 x dropper bottles of methyl red indicator
Equipment:
12 x buret, buret clamps and ring stands
Student set-up:
Preparation:
Waste:
Titrated solutions are neutral and can go down the drain.
Measuring Electrochemical Cells
This is currently and unfinished lab.
Reagents:
Solutions of 0.1 M AgNO3, zinc nitrate, iron nitrate, copper
nitrate, and iodine.
Equipment:
Student set-up:
Preparation:
Waste: