development ofdevelopment of microscale …spec/microscalechemmeeting.pdfdepartment of applied...

The 92th Chemical Society of Japan Spring Meeting, Mar. 25, 2012, Tokyo

大学教育に適用可能な物理化学実験のマイクロスケル化の取り組み（１）マイクロスケール化への取り組み（１）

Development of microscale experimentsDevelopment of microscale experiments in physical chemistry for chemical education

for ndergrad ates part Ifor undergraduates - part I

Shota Kuwahara, Akira Takeda, Tomorou Miyahara, Naomi Tsuchiya, Kenji Katayama

Department of Applied Chemistry, Chuo University

Outline

1. Introduction

1 1 Mi l i t f i it1-1. Microscale experiment for university

1-2. Typical curriculum of Physical Chemistry

1-3. Theme of microscale experiments

2. Development of microscale experiment

2-1. The gas lawg

2-2. Liquid-liquid equilibria of binary systems

3. Conclusion

2010/ 6/14 @ Chuo Univ.

IntroductionMicroscale experiment

→ Experiment using a few reagent or small instrument

Advantage

・Less experimental risksp

・Reduce waste

・Lower costs for chemicals d i

・Save time for preparation

・Shorter experimental times

and equipment


・More time for evaluation

・Smaller working space

o e e o e a ua oand discussion about result

IntroductionMicroscale experiment

→ Experiment using a few reagent or small instrument

Advantage

・Less experimental risks For universityp

・Reduce waste

・Lower costs for chemicals d i

・Budget: 10 times larger than high school

・Mechanical equipments can be used.

・Save time for preparation


and equipment Ex. Pipette, Magnetic Stirrer, Heater…

・Analytical equipments can be used.Ex. UV/Vis, IR, Chromatography…・Shorter experimental times

・More time for evaluation

・Smaller working space ・Mathematical calculations can be made by a computer.

, , g p y

St d t h i t t i h i to e e o e a ua oand discussion about result

I thi k h d l d i l i t i

・Students have interests in chemistry.

In this work, we have developed microscale experiments in physical chemistry for chemical education of undergraduates.

Scheme of development of microscale experiments

Pl iSelection of theme

Planning&

Development

Check Trial experimentVerification Trial experimentVerification

Typical curriculum of Physical Chemistry

1. Property of gas

2. Enthalpy

3 Entropy3. Entropy

4. Mixture of chemicals

5. Phase diagram

6. Equilibriumq

7. Electrochemistry


1. Property of gas The work of gas

2. Enthalpy

3 Entropy

Calorimetry

3. Entropy


5. Phase diagram

6. Equilibrium

Liquid-liquid equilibria of binary systemsq

7. Electrochemistry Electromotive force of electrochemical cellselectrochemical cells

Z. Szafran, R. M. Pike, J. C. Foster, “Microscale General Chemistry Laboratory”, Wiley.東海林恵子、荻野和子, 化学と教育 49 712 (2001) .

Microscale experiment 1 - The work of gasPoint

1. Experience the Boyle’s law.

2. Understand the difference between reversible and irreversible compression.irreversible compression.

Physical Chemistry Atkins sixth editionPhysical Chemistry, Atkins, sixth edition

Microscale experiment 1 - The work of gasPoint

1. Experience the Boyle’s law.Microscale experiment

2. Understand the difference between reversible and irreversible compression.

Force gaugeirreversible compression.

AdAdvantage

1. Simple experimental setup

2. Easy handling

3. Directly and easily i h

Syringe

measuring the pressureZ stage

Definition of the work of gas – the Boyle’s law

F

Pdz

P

CompressedVV

PdVAdzPdzFdwin =×=×=

∫=2

1

V

Vin PdVw

Experimental – reversible vs irreversible compression

Reversible ⇒ Press the syringeReversible ⇒ Press the syringe slowly

Irreversible ⇒ Press the syringe quickly

Analysis of obtained results by using PC and software

Making & analysis of pressure (p) – volume (V) curve

Work Theoretical Reversible Irreversible

W[J] 422 486 537W[J] 422 486 537

Microscale experiment 2 – Binary phase diagramPoint

1. Understand how to make d bi h diand use binary phase diagram.

2. Understand the phase rule and liquid liquid equilibriaand liquid-liquid equilibria.

Microscale experiment 2 – Binary phase diagramPoint

1. Understand how to make d bi h di

Microscale experiment

Thermometerand use binary phase diagram.

2. Understand the phase rule and liquid liquid equilibria Screw bottle x 6and liquid-liquid equilibria.

Ad

Screw bottle x 6(1 mL)

Advantage

1. Smaller working space

2. Enough time to do further experiments (Ex. Lever rule)

3 E t

Hot magnetic stirrer

3. Easy to compare mass fraction with liquid mutual solubility

Liquid-liquid binary phase diagram Methanol/Cyclohexane system– Methanol/Cyclohexane system –

Heating

Cooling

P = 2 P = 1Two phase system Single phase

Record the temperature of cloud points

Liquid-liquid binary phase diagram Methanol/Cyclohexane system– Methanol/Cyclohexane system –

The error of the temperature is within 1 OCThe error of the temperature is within 1 C.

H. Matsuda et al., J. Chem. Eng. Data 43 184 (2003).

Further experiment – the lever rule

a

bb

The lever rule

（nA, nB：the mass of each phase）bBaA lnln ×=×


a

bb

Mass fraction [-] Methanol mass fraction [-]

Phase a Phase bThe lever rule 0.23 0.77

The lever rule 0.64Experimental

Experimental


aMass fraction of methanol (a) = ρ(a) x V(a)

V(a)

b

ρ(a) x V(a)

Mass fraction of methanol (b) (b) V(b)

V(b) b= ρ(b) x V(b)



The lever rule 0.64Experimental

Experimental 0.26 0.74

Further experiment – the lever ruleRefractrometer

a0.84

0.86Refractrometer

b0.8

0.82

ve in

dex

b

0.76

0.78

Ref

lact

iv

0.741.34 1.345 1.35 1.355

Mass fraction of methanol [-]



The lever rule 0.64Experimental 0.65

Experimental 0.26 0.74

Rating and comments – from undergraduates –

1 Th l1. The gas laws1. Easy to operate

2 Easy to understand2. Easy to understand

3. The experimental error depends on operators.depends on operators.

2. Binary phase diagram

1. Easy to operate

2. Well understand the phase diagram through the microscaleexperiments

3 Long time (~ 1 h) is required3. Long time (~ 1 h) is required to observe the phase change.

Conclusion

1. We have succeeded in developing the microscaleexperiments in physical chemistry for chemical d ti f d d t t d teducation of undergraduate students.

2. Reversible and irreversible compression of the gas p glaw was confirmed through microscale experiments.

3 Liquid liquid binary phase diagram of3. Liquid-liquid binary phase diagram of methanol/cyclohexane system was successfully made by microscale experiments.by microscale experiments.

4. It was confirmed that the developed microscalei t h d d t di f bj t iexperiments enhanced understanding of subjects in

physical chemistry for undergraduate students.

Web of microscale experimenthttp://www.chem.chuo-u.ac.jp/~spec/microscale_pre.html

1H21H2--09 09 2012/3/252012/3/25

Development of microscale experiments Development of microscale experiments i h i l h i t f h i l d tii h i l h i t f h i l d tiin physical chemistry for chemical educationin physical chemistry for chemical education

for undergraduatesfor undergraduates--partpartⅡⅡ大学教育に適用可能な物理化学実験の大学教育に適用可能な物理化学実験のマイクロスケル化への取り組みマイクロスケル化への取り組み(2)(2)マイクロスケール化への取り組みマイクロスケール化への取り組み(2)(2)

Naomi TsuchiyaNaomi Tsuchiya, Taeko Yabe, Shota Kuwahara,, Taeko Yabe, Shota Kuwahara,Kenji KatayamaKenji Katayama

Department of Applied Chemistry, Chuo UniversityDepartment of Applied Chemistry, Chuo University


1. Property of gas

2. Enthalpy

3 Entropy3. Entropy


5. Phase diagram

6. Equilibriumq

7. Electrochemistry

2


1. Property of gas Work of gas

2. Enthalpy

3 Entropy

Calorimetry

3. Entropy

4. Mixture of chemicalsPh di5. Phase diagram

6. Equilibrium

Phase diagram for binary liquid system

q


3


1. Property of gas Work of gas

2. Enthalpy

3 Entropy

Calorimetry

3. Entropy

4. Mixture of chemicalsPh di5. Phase diagram

6. Equilibrium

Phase diagram for binary liquid system

q


4

Calorimetry

To measure neutralization heat by i i id d b d

Conventional

mixing acid and base and dissolution heat by dissolving alkali metal salt to water

SHIMADZU

5

Calorimetry


Conventional

mixing acid and base and dissolution heat by dissolving alkali metal salt to water

100 mL

6

Calorimetry


Microscale

mixing acid and base and dissolution heat by dissolving alkali metal salt to water 10 mL

12 cm

bottle

Advantage

5 cm15 cm

12 cmAdvantage

A few reagentSmall heat capacity of container A few reagentSmaller working space

Point

To calculate ⊿H by measuring ⊿TZ S f R M Pik J C F t

7

To discuss the correlation between⊿HHyd and ion radius of alkali metal

Z. Szafran, R.M.Pike, J.C.Foster, MICROSCALE GENERAL CHEMISRY LABORATORY, Wiley (1993)

Neutralization of HCl and NaOH

26

28

℃]

24

26

erat

ure[℃

⊿TReaction heat is consumed

for the temperature

22Tem

pe

⊿T for the temperature increase of not only solvent but also container

200 60 120 180 240

Time[s]Time[s]

TCTmCH containerp Δ+Δ=Δ− molkJH /4.66=⊿

lkJH /556⊿8

p molkJH ltheoretica /5.56⊿

Dissolution of alkali metal salt totwater

M+(g)+X-(g)

ΔHHydΔHLTheoretical22

26

℃]

NaI

N Cl

M+(aq)+X-(aq)18

mpe

ratu

re[℃

KI

NaCl

MX(s)

( q) ( q)ΔHSol

Experimental10

14Tem

KCl

0 100 200 300Time[s]

⊿H ⊿H KI KCl NaI NaCl

Hydration enthalpy

⊿Hexperimental18.9kJ/mol17.9kJ/mol7 1kJ/ l

⊿Htheoretical20.3kJ/mol17.2kJ/mol7 5kJ/ l

KIKClN I

KI KCl NaI NaCl

‐630 ‐699 ‐712 ‐785

9

-7.1kJ/mol1.79kJ/mol

-7.5kJ/mol3.9kJ/mol

NaINaCl

Ion radiusBigger Smaller

Electromotive force of electrochemical llcell

To measure electromotive forces of a Daniel cell

Conventional

[ Zn|Zn(NO3)2||Cu(NO3)2|Cu ], changing temperature and concentrations of solutions

10

Electromotive force of electrochemical llcell

To measure electromotive forces of a Daniel cell

Microscale

[ Zn|Zn(NO3)2||Cu(NO3)2|Cu ], changing temperature and concentrations of solutions

Diameter2.2 cmAdvantage

8 cmEasy to compare A few reagent

12.5 cmTo calculate ⊿G,⊿S,⊿H by

Point

ymeasurement of electromotive force of Daniel cellTo confirm the Nernst’s equation

11

To confirm the Nernst s equation by changing the concentration of electrolyte solutions

東海林恵子, 荻野和子, 化学と教育, 49, 712, (2001)

Electromotive force of Daniel cell

G ⎞⎛⊿

Nernst’s equationThermodynamic function of state

nFEG −=⊿ STG

p

−=⎟⎠

⎞⎜⎝

⎛⊿

⊿

STGH ⊿⊿⊿][][ln 2

2

+

+

−=CuZn

nFRTEE ο

y = -0.0142x + 1.34341

e [V

]

y = -0.0098x + 0.9496

1.1

e[V

]

STGH ⊿⊿⊿ += ][CunF

0.9

mot

ive

forc

e

1

mot

ive

forc

e0.7

0.8

Ele

ctro

m

0 8

0.9

Ele

ctro

m0.7

25 30 35 40 45 50Temperature[℃]

0.8-8 -6 -4 -2 0 2 4 6 8

ln[Zn2+]/[Cu2+][-]

molKJS ・⊿ /62740VE 11⊿ lkJG /3212⊿12molkJG /8.190−=⊿

molKJS ・⊿ /6.2740−=molkJH /5.1007−=⊿VE 99.0=⊿

VE ltheoretica 1.1=⊿ molkJG ltheoretica /3.212−=⊿

Rating and commentsf d d tfrom undergraduates

Ease ofoperation

Daniel cell

Easy to understandEasy to operate

2345

operation

ReagentSafety y

Not care for the dangerous reagents because of small

12 volumeSafety

Difficult matters can be d t d i ll

quantityUnderstandingTime required

Calorimetry understood visually Think over because of doing experiments4

5

Ease ofoperation

Calorimetry

doing experiments aloneSusceptible to errors1

234

ReagentvolumeSafety

Susceptible to errors because of small quantity

UnderstandingTime required 13

Conclusion

We could develop microscale experiments according to th i l f h i l h i t f h i lthe curriculum of physical chemistry for chemical education for undergraduatesーThe gas lawsThe gas lawsーCalorimetryーLiquid-liquid equilibria of binary systemsq q q y y－Electromotive force of electrochemical cells

Microscale experiments can be easily introduced toMicroscale experiments can be easily introduced to students and would help understanding theories

14Web of microscale experimenthttp://www.chem.chuo-u.ac.jp/~spec/microscale_pre.html

development ofdevelopment of microscale …spec/microscalechemmeeting.pdfdepartment of applied...

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