Exp. B Bomb Calorimetry - People 210 Lab Manual Extra Pages.pdf · Exp. B Bomb Calorimetry . ......

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Bomb Calorimetry:6 © P.S.Phillips August 2, 2009

Exp. B Bomb Calorimetry

PRELAB: The prelab. must completed prior to the beginning of the lab period and handed in before any lab work may be started.

Make sure you read the safety instructions. See the start of the lab. manual for further details.

Name: Purpose of experiment (briefly).

Please answers the questions overleaf:

1) What is the recommended mass of analyte to be placed in combustion cup? What may happen if this value is exceeded significantly?

2) Before firing the bomb, the temperature is read a number of times. What is the interval and number of readings suggested for this process?

3) The calorie and the joule are both units of energy. What is the conversion factor to convert calories into joules? The Calorie unit (capital “C”) is often used to measure nutritional energy equivalents. How many calories (lower case “c”) are there in one Calorie?

Name: Experiment: B

Chemistry 210

Lab. Report Title Page.

BOMB CALORIMETRY: THE ENERGY OF COMBUSTION Date Experiment Performed: Partners Name:

Complete and staple one of these sheets (or a copy) to the front of each lab. Do not submit lab. reports in binders or books unless otherwise instructed.

Lab. Profs. Name:

For lab. profs. use only:

Your Mark _____/ Comments:

Part A. Calibration Mass of benzoic acid pellet __________ g

Starting Temperature (obtained graphically) __________ C

Final Temperature (obtained graphically) __________ C

Length of wire consumed __________ cm

Wire correction __________ J

Energy equivalent for the calorimeter __________ kJ/C

Calibration. Time Temperature Time Temperature

Part B. Heat of Combustion

Mass of ____________________ pellet __________ g

Starting temperature (from graph) __________ C

Final temperature (from graph) __________ C

Length of wire consumed __________ cm

Wire correction __________ J

Energy of combustion of sample __________ kJ

Energy of combustion per gram of sample __________ kJ/g

Energy of combustion per mole of sample, ΔE __________ kJ/mol

Sample Run. Time Temperature Time Temperature

1) ) Calculate the enthalpy of combustion, ΔHcomb., of the cereal, in kJ/mole, from your experimental data. (Note the kJ/mole, that implies the molecular weight, assume the cereal is pure carbohydrate, write a balanced equation, and go from there). Strictly you should correct ΔEcomb. to ΔHcomb., but they turn out to be nearly identical for cereal (why?). Compare your experimental value with a “literature” value and explain any difference. Quote the reference source. (The latter will be the box in the supermarket if your sample was a cereal). Also, compare the value with glucose. Explain any significant differences from the latter.

2) List the possible sources of error and their effects in bomb calorimetry. Where applicable, state how the equipment design of the instrument minimizes those errors.

Exp. C c.m.c.

Micelles:2 © P.S.Phillips August 2, 2009

1) What important property is possessed by micelle-forming materials? Give the name of the property and describe the structural characteristics.

2) What is the diameter of a typical micelle? How many surfactant molecules will it contain ?

3) What is equivalent conductance.

Name: Experiment: C

Chemistry 210

MICELLES Date Experiment Performed: Partners Name:

Complete and staple one of these sheets (or a copy) to the front of each lab.

Do not submit lab. reports in binders or books unless otherwise instructed.

Lab. Profs. Name: For lab. profs. use only:

Micelles:2 © P.S.Phillips August 2, 2009

Exp. E Partitioning

Purpose of experiment (briefly).

1) In this experiment, the acid-base indicator is highly soluble in water at high pH but at low pH it is more soluble in octanol. Why ?

2) What species are we measuring by monitoring the absorbance at 508 nm?

3) Why do you need to work in the fume hood for this experiment ?

Name: Experiment: E

Chemistry 211.

PARTITION COEFFICIENT FORMAL LAB.: PLEASE ATTACH THIS TO THE FRONT OF THE REPORT

Date Experiment Performed: Partners Name:

Lab. Profs. Name:

Your Mark _____/ 10 Comments:

Exp. H Solution Calorimetry

1) The chart recorder is zeroed on the left side for the glycine part of the experiment and on the right side for the TRIS part of the experiment. Why are the two parts zeroed differently ?

2) The temperature change is measured from the plot of temperature vs. time. What point is best to measure ∆Tc? Would ∆Tc be different at some other point?

Name: Experiment: H

Chemistry 210

HEAT OF SOLUTION

FORMAL LAB REPORT. ATTACH THIS COVER PAGE. Date Experiment Performed: Partners Name:

Marker’s Name: For lab. profs. use only:

June 6, 2008 EXPERIMENT K:1

Exp. K Kinetics

Make sure you read the safety instructions. See the start of the lab. Manual for further details.

EXPERIMENT K:2 June 6, 2008

1) Why is the enzyme catalase used as the catalyst in one of the runs rather than iodide ?

2) Why does the water level in the two burettes need to be equal when reading the volume change ?

3) The rate of production of oxygen gas depends primarily on the decomposition reaction but also on a mechanical aspect of the experimental apparatus. What is this mechanical aspect and why does it influence the rate of gas production ?

Name: Experiment: K

Chemistry 201.

RATE OF DECOMPOSITION OF H2O2 Date Experiment Performed: Partners Name:

Marker’s Name:

For marker’s use only:

Your Mark _____/ 10 Comments:

Run 1.

Time Volume Time Volume Time Volume Time Volume

Run 2.

Time Volume Time Volume Time Volume Time Volume

Room Temperature: ___________ C Room Pressure: ___________ mmHg

Vi(trial 1):___________ mL Vi(trial 2):____________ mL

1. Using the data from Run 1 obtain the order of the reaction with respect to H2O2. You will need the value of PoH2O

at 25C. C should be in mole.L-1 and time in seconds. (You’ll need to add a few sheets of graph paper to these data sheets).

2. From the first few data points in Runs 1 and 2, obtain the values for dC/dt (or d[O2]/dt) and determine an integer value for the order of the reaction with respect to I-.

3. Determine the average rate constant for the reaction at 25C

4. Is the half-life of this reaction independent of the [H2O2] for a particular concentration of catalyst? Explain.

Exp. O Osmosis

Permeability:6 © P.S.Phillips August 2, 2009

1) In this experiment, a plot of ln(Vi°-mi(t)) vs. t produces a straight line. What quantity can we obtain from the slope of this line? Give the appropriate equations.

2) What is the most important step that should be performed before weighing the dialysis bag ?

3) How does Gortex work ? (Just for fun).

Name: Experiment: O

Chemistry 210

OSMOSIS & PERMEABILITY

FORMAL LAB.: PLEASE ATTACH THIS TO THE FRONT OF THE REPORT Date Experiment Performed: Partners Name:

Lab. Profs. Name: For lab. profs. use only:

Permeability:8 © P.S.Phillips August 2, 2009

Phase Diagram:1 August 2, 2009

Exp. P Phase Diagram

August 2, 2009 Phase Diagram:2

1) What masses of biphenyl and naphthalene are required to make exactly 10.0 g of 0.75 mole fraction (X) of naphthalene ?

2) The heat of fusion is found from the slope of the line obtained by plotting a portion of the cooling curve data. For this graph, what is plotted on the y and x axes ?

3) What are the units of the slope from the plot? How do you convert this value into ∆Hfus ?

Name: Experiment: P

Chemistry 210

A SIMPLE PHASE DIAGRAM Date Experiment Performed: Partners Name:

Lab. Profs. Name:

Run 1.

Time Temperature Time Temperature

Run 2.

Time Temperature Time Temperature

Your data. Weight of diphenyl _______________ g Weight of napthalene _______________ g Mole fraction(assigned) _______________ Mole fraction(actual) _______________ Break _______________ C _______________C Arrest _______________ C _______________C QUESTIONS. 1) From your data determine ΔHfus for both naphthalene and diphenyl and compare with the literature values.

2) Discuss your cooling curve in terms of the phase rule (just annotate one of your graphs). Use these pages or attach your own graphs.

August 2, 2009 Phase Diagram:10 August 2, 2009 Phase Diagram:10

02/08/2009 Spectrophotometry:1

Exp. S Spectrophotometry

Spectrophotometry:2 02/08/2009

1) When making a dilution series, what 3 rules should be followed? What may occur if these rules are not followed ?

2) What safely precautions are followed when handling and then boiling the solution containing concentrated sulphuric acid in Procedure 1 ?

3) What function do the persulphate and periodate ions serve in this experiment ?

Name: Experiment: S

Chemistry 210

SPECTROPHOTOMETRIC ANALYSIS Date Experiment Performed: Partners Name:

Lab. Profs. Name:

Unknown No. __________ Please attach your own copy of the spectra to the back.

Solution Conc. mol/L Abs. at ________nm Abs. at ________nm

Chromium standard

Manganese standard

Conc. chromium in unknown

Conc. manganese in unknown.

1) Calculate the ε values at each wavelength for the two standards.

2) Calculate the concentration of chromium and manganese in the unknown.

3) Briefly outline your dilution procedure. Mass of potassium dichromate __________________ g Conc. of stock 1 ________________ mM Conc. of stock 2 ________________ mM 4) It might have been more convenient to use 1, 2, 3, 4, 5 mL pipettes to prepare the calibration standards. Why don’t we use them?

5) Are your results consistent with what you know about the composition of steels ?

6) Compare the results of procedures I and II and comment. (Compare extinction coeefs.). Attach calibration graph.

Exp. T Titrimetry

1) What is the pH of a solution of 0.100M HCl?

2) Why does glycine have two pK values? Give the structure and show the two protonation steps that give rise to the two pK values.

Name: Experiment: T

Chemistry 210

ACID-BASE TITRATION

Lab. Profs. Name:

Exp. W Wine

1) Define buffer capacity ?

2) What is the Henderson-Hasselbach equation? Based on the equation, when will pH = pK? How is this related to Ve, the equivalence point?

Name: Experiment: W

Chemistry 210

BUFFER CAPACITY OF A WINE

Lab. Profs. Name:

Exp. B Bomb Calorimetry - People 210 Lab Manual Extra Pages.pdf · Exp. B Bomb Calorimetry . ......

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