„ Instant Chemistry“ Viktor Obendrauf (Graz, Austria) [email protected] TEACHING CHEMISTRY...
-
Upload
reynard-mosley -
Category
Documents
-
view
225 -
download
2
Transcript of „ Instant Chemistry“ Viktor Obendrauf (Graz, Austria) [email protected] TEACHING CHEMISTRY...
„„Instant Chemistry“Instant Chemistry“
Viktor Obendrauf (Graz, Austria)Viktor Obendrauf (Graz, Austria)
[email protected]@obendrauf.com
TEACHING CHEMISTRY WITH TEACHING CHEMISTRY WITH SMALL SCALE AND MICROSCALE SMALL SCALE AND MICROSCALE
GAS REACTIONS INCLUDING GAS REACTIONS INCLUDING EXPLOSIONSEXPLOSIONS
International Christian University, TokyoAugust 16 -18 2007
Chemical Society of Japan, TokyoJapan ICU Foundation (JICUF)
V.O.
• are as safe as possible for are as safe as possible for the teacher and the the teacher and the studentsstudents
• are are time-savingtime-saving (preparation, (preparation, performing, clean up) performing, clean up)
• are non-polluting to the are non-polluting to the environment (reduction environment (reduction of waste)of waste)
• are as safe as possible for are as safe as possible for the teacher and the the teacher and the studentsstudents
• are are time-savingtime-saving (preparation, (preparation, performing, clean up) performing, clean up)
• are non-polluting to the are non-polluting to the environment (reduction environment (reduction of waste)of waste)
V.O.
• are are cost-savingcost-saving (materials, (materials, chemicals)chemicals)
• can be referred to the every can be referred to the every day life day life
• can be used to illustrate can be used to illustrate chemical theory chemical theory
• are are cost-savingcost-saving (materials, (materials, chemicals)chemicals)
• can be referred to the every can be referred to the every day life day life
• can be used to illustrate can be used to illustrate chemical theory chemical theory
V.O.
• Is it really necessary to have a fume Is it really necessary to have a fume hood for hazardous gases even hood for hazardous gases even involving very small amounts of involving very small amounts of substances?substances?
• Is it really necessary to have a fume Is it really necessary to have a fume hood for hazardous gases even hood for hazardous gases even involving very small amounts of involving very small amounts of substances?substances?
Oh, so many fixing stands!But what‘s about the reaction?
V.O.
• Is it really necessary that chemical Is it really necessary that chemical demonstrations must be performed demonstrations must be performed at the teacher‘s table exclusively?at the teacher‘s table exclusively?
• Is it really necessary that chemical Is it really necessary that chemical demonstrations must be performed demonstrations must be performed at the teacher‘s table exclusively?at the teacher‘s table exclusively?
What‘s about the safety shield?
V.O.
• Is it possible to use the same material Is it possible to use the same material with the same size for chemical with the same size for chemical demonstrations and for student‘s demonstrations and for student‘s activities?activities?
• Do we have hands-on experiments Do we have hands-on experiments only for physics teaching? only for physics teaching?
• Is it possible to use the same material Is it possible to use the same material with the same size for chemical with the same size for chemical demonstrations and for student‘s demonstrations and for student‘s activities?activities?
• Do we have hands-on experiments Do we have hands-on experiments only for physics teaching? only for physics teaching?
What‘s about the safety shield?
V.O.
Would it be convenient to change Would it be convenient to change demonstrations to microscale to demonstrations to microscale to perform gas experiments closer perform gas experiments closer to the students?to the students?
Would it be convenient to change Would it be convenient to change demonstrations to microscale to demonstrations to microscale to perform gas experiments closer perform gas experiments closer to the students?to the students?
Oh, so many fixing stands!But what‘s about the reaction?
V.O.
• Is it possible to use a portable Is it possible to use a portable apparatus which apparatus which needs no fixing stands?needs no fixing stands?
• Is it possible to use a portable Is it possible to use a portable apparatus which apparatus which needs no fixing stands?needs no fixing stands?
Oh, so many fixing stands!But what‘s about the reaction?
Select your 2 mostSelect your 2 mostfavourite wishesfavourite wishes
in this list ofin this list of5 wishes5 wishes
What do Chemistry teachers really want?What do Chemistry teachers really want?((Results of anResults of an inquiry among 2000 Chemistry teachers)inquiry among 2000 Chemistry teachers)
Percent (response from 632 colleagues in autumn 1999)
54,6
43,2
37,4
36,3
22,3
0 20 40 60
More time fordiscussing newtopicsMore money topurchasematerialMore textbookstesteddidacticallyMore time forrepeating thecontextsMore recipes fortime-savingHands-on
V.O.
V.O.
Chemical experiments are an
Chemical experiments are an
essential part of chemical education.
essential part of chemical education.
Could it be, that a very
Could it be, that a very time-consumingtime-consuming
experiment is mainly food for the playing
experiment is mainly food for the playing
instinct of the teacher
instinct of the teacher ??
Could a Could a time-consuming
time-consuming experiment be rather
experiment be rather
boring and useless for improving the
boring and useless for improving the
knowledge of the students
knowledge of the students ??
Is there enough Is there enough timetime to teach, to discuss and to
to teach, to discuss and to
repeat the chemical background and contexts
repeat the chemical background and contexts ??
INSTANT CHEMISTRYINSTANT CHEMISTRYTwo Criteria for Chemical Hands-on:Two Criteria for Chemical Hands-on:
•Time-savingTime-saving: The experiment should : The experiment should be done within a couple of minutes be done within a couple of minutes including clean up.including clean up.
•Cost-savingCost-saving: The experiment should : The experiment should involve familiar and cheap every day involve familiar and cheap every day common material.common material.
INSTANT CHEMISTRYINSTANT CHEMISTRY
Examples involvingExamples involving
Chlorine Hydrogen, Chlorine Hydrogen, Acetylene, Oxygen, AmmoniaAcetylene, Oxygen, Ammonia
Well known problems with Well known problems with
classical generation of gasesclassical generation of gases
0 0 +1 -10 0 +1 -1 Na + ½ ClNa + ½ Cl22 NaCl NaCl
Large Scale ?Large Scale ?
Complicated arrangements Complicated arrangements too far away from the too far away from the
studentsstudents
Time-consumingTime-consuming (preparation, clean up) (preparation, clean up)
Expensive materialExpensive material
Great demand of chemicals because Great demand of chemicals because of big flasks containing airof big flasks containing air
Noisy and bad positioned fume hoodsNoisy and bad positioned fume hoodsGeneration of wasteGeneration of waste
0 0 +1 -10 0 +1 -1 Chlorine: ½ ClChlorine: ½ Cl22 + Na + Na NaCl NaCl
What about going Smallscale
What about going Smallscale
or Microscale without
or Microscale without
changing the system?
changing the system?
SmallscaleSmallscale
or Microscale ?or Microscale ?
0 0 +1 -10 0 +1 -1 Chlorine: ½ ClChlorine: ½ Cl22 + Na + Na NaCl NaCl
Danger and Disadvantages:Danger and Disadvantages:
Complicated arrangementsComplicated arrangements
Fixed at the teacher‘s tableFixed at the teacher‘s table
Rather time-consuming Rather time-consuming (preparation, clean up) (preparation, clean up)
Expensive materialExpensive material
• Test tube (Fiolax 16/160mm)
• Rubber stopper Verneret (soft material, 18D)
• 2 Needles in the stopper (1,2/40 mm; tips cut)
• 1 Syringe Normject 2mL (prepared for hard to move)
• 1 Syringe ONCE 20 ml (plunger rubber greased with special silicon oil)
• 1 Syringe 10 ml filled with activated charcoal in grains v.o.
Low Cost Generator Low Cost Generator for various Gases for various Gases
V.O. ©
Rubber stopper Rubber stopper Verneret 18DVerneret 18D
Test tube Test tube Fiolax 16/160 mmFiolax 16/160 mm
2 Needles 1,2/40 mm2 Needles 1,2/40 mm
2ml syringe 2ml syringe (plunger hard to move)(plunger hard to move)
20ml syringe ONCE 20ml syringe ONCE (plunger greased with (plunger greased with special silicon oil)special silicon oil)
Cut tips
V.O. ©
Gas kit I V.O. © Gas kit II V.O. ©
Low-cost – Generation of Cl2
KMnOKMnO44 (s) (s)
HCl HCl conc.conc.HCl HCl conc.conc.
Mn Mn 2+ 2+ (aq)(aq)
ClCl22-storage-storage++
ClCl2 2 (g)(g)
V.O.
V.O.
0 0 +1 -10 0 +1 -1 Sodium chloride ½ ClSodium chloride ½ Cl22 + Na + Na NaCl NaCl
Reaction productReaction product+ 1 drop of water+ 1 drop of wateron a microscope slideon a microscope slidewater evaporated,water evaporated,stereo microscope stereo microscope 40 times +FLEXCAM40 times +FLEXCAM
Low-cost – Generation of H2
Zn (s)Zn (s)
HCl HCl conc.conc.HCl HCl conc.conc.
Zn Zn 2+ 2+ (aq)(aq) + 2 Cl+ 2 Cl- - (aq)(aq)
HH22-storage-storage++
HH2 2 (g)(g)
• Test tube Fiolax 16/160Test tube Fiolax 16/160• 15 ml Hydrogen15 ml Hydrogen• Procedure:Procedure:
15 ml Hydrogen are 15 ml Hydrogen are
injected into the test tubeinjected into the test tube
and lightedand lighted
• f = c . f = c .
f = 340 m.sf = 340 m.s-1 -1 .64.10.64.10-2 -2 mm-1-1==
531 Hz531 Hz f = 340 m.sf = 340 m.s-1 -1 .0,5.10.0,5.10-2 -2 mm-1 -1 ==
68.000 Hz68.000 Hz
Test tube as a Kundt‘s Test tube as a Kundt‘s TubeTube
J. W. Döbereiner (1780-1849)J. W. Döbereiner (1780-1849)Döbereiner‘s Lighter Jena 1823
Ignition by finely divided platinum powder and a stream of hydrogen directed at it
Modelling experimentModelling experiment
©V.O.
Low Cost Electrolysis of WaterLow Cost Electrolysis of Water
Low Cost Electrolysis of WaterLow Cost Electrolysis of Water
Plus: Plus: 2 OH2 OH-- (aq) (aq) →→ H H22O + ½OO + ½O2 2 +2e+2e--
Minus:Minus:2 H2 H22O (l) + 2 eO (l) + 2 e-- →→ H H22 (g) + 2 OH (g) + 2 OH--
Redox: HRedox: H22O (l) O (l) →→ H H22 (g) + ½O (g) + ½O2 2
CO32- + H2O →
HCO3- + OH-
©V.O.
Detection of O2
Detection of H2
Collection of O2
Electrolysis
Hydrogen-chlorine reaction: HHydrogen-chlorine reaction: H22 + Cl + Cl22 2 HCl 2 HCl
10 mL chlorine
+ 10 ml pure hydrogen
Flash (LZ 20)
KMnOKMnO44 Zn (Grains)Zn (Grains)
HClHCl HClHCl
Low-cost – Generation of C2H2
CaCCaC22 (s) (s)
HH22OOHH22OO
CaCa2+ 2+ (aq)(aq) + 2 OH+ 2 OH- - (aq)(aq)
CC22HH22
storagestorage
++
CC22HH2 2 (g)(g)
20 ml Chlorine20 ml Chlorine 20 ml Acetylene20 ml Acetylene Insulation Insulation
(Electricity (Electricity wires removed)wires removed)
200 ml 200 ml ErlenmeyerErlenmeyer
-1 +1 0 0 +1 -1-1 +1 0 0 +1 -1
CC22HH22 + Cl + Cl22 2 C + 2 HCl 2 C + 2 HCl
CC22HH22 + Cl + Cl22 C C22HH22ClCl22
Low-cost – Generation of O2
MnOMnO22--
TabsTabs
HH22OO22HH22OO22
OO22
storagestorage
++
OO2 2 (g)(g)
0 -1 +1 +4 -2 +1 -20 -1 +1 +4 -2 +1 -2 Oxygen: 2½ OOxygen: 2½ O22 + C + C22HH2 2 2 CO 2 CO22 + H + H22OO
OO22 Mixture of
10 ml Oxygen
4 ml Acetylene
G. Arcimboldo: Ignis (1566)Kunsthistor. Museum Wien
CHCH33-CH-CH22-CH-CH22-CH-CH22-CH-CH22-CH-CH22-CH-CH22-CH-CH3 3 CHCH33-CH-CH22-CH-CH22-CH-CH22-CH-CH22-CH-CH22-CH-CH22-CH-CH22• + H•• + H•
4 H• + •O-O• 4 H• + •O-O• 2 H 2 H22OO
Candle vapour ignition
H2
Oxygen generation
Hydrogen generation
O2
Inverse flames – Small scale versionInverse flames – Small scale version
V.O.
Microscale Microscale Ammonia Ammonia FountainFountain
NHNH33(g) + H(g) + H22O O →→ NHNH44++ + OH + OH――
INSTANT CHEMISTRYINSTANT CHEMISTRY
Some more examples involvingSome more examples involving
Sulphur dioxide Sulphur dioxide Hydrogen sulphide Hydrogen sulphide
Carbon monoxide Carbon monoxide
HH 22SOSO 44
NaNa 22SOSO 33
SOSO22
+4 -2 +1 -2 +1 -2 0+4 -2 +1 -2 +1 -2 0
Sulphur dioxide: SOSulphur dioxide: SO22 + 2H + 2H22S S 2H 2H22O + 3 SO + 3 S
HH22SSHCl HCl
FeSFeS
+4 -2 +1 -2 +1 -2 0+4 -2 +1 -2 +1 -2 0
Sulphur dioxide: SOSulphur dioxide: SO22 + 2H + 2H22S S 2H 2H22O + 3 SO + 3 S
(20 ml)(20 ml)(10 ml)(10 ml)
Carbon Carbon monoxide as a monoxide as a reducing agentreducing agent
HCOOH → CO + H2OH2SO4
Desulphurisation plant:Desulphurisation plant:
+4 -2 +2 +4 -2 +0 +2 +6 -2 +4 -2+4 -2 +2 +4 -2 +0 +2 +6 -2 +4 -2
SOSO22 + CaCO + CaCO33 + ½O + ½O22 CaSO CaSO4 4 + CO+ CO22
INSTANT CHEMISTRYINSTANT CHEMISTRY
Some more examples involvingSome more examples involving
Nitrous Oxide Nitrous Oxide Carbon dioxide Carbon dioxide
Lighter Gas Lighter Gas Lighter FuelLighter Fuel
With the help of a With the help of a wine bottle opener...wine bottle opener...
Gases and Vapour in the Market place: A great source for N2O and CO2
Gases and Vapour in the Market place: A great source for N2O and CO2
Critical point of Nitrous oxideCritical point of Nitrous oxide
36,5°C
72,6bar
TT
72,6bar
PP
Nitrous
Oxide
Cotton soakedin LiquidNitrogen
Easy Whip 0,5 l 29 Euro Whipped cream charger: 0,26 Euro
Fire extiguishing and similar to gun cotton….
Easy Whip 0,5 l 29 Euro Soda bottle charger: 0,15 Euro
Gourmet Whip 0,5 l 65 Euro Sahnekapsel: 0,26 Euro
Funktioniert nicht mit Aufsatz der Sodawasser- Bottle !
Funktioniert nicht mit Aufsatz der Sodawasser- Bottle !
Gourmet Whip 0,5 l 65 Euro Sahnekapsel: 0,26 Euro
Bürkle Snowpack: 175 Euro exkl.
30 g/ dry ice per minute
10 l Carbon dioxide bottle with with a special valve: 331 Euro
Easy Whip 0,5 l 29 Euro Whipped cream charger: 0,26 Euro
3/2004
LOW COST CANNON for stoichiometric mixtures
©V.O.
1
CC44HH1010 + 13 N + 13 N22O O → → 4 CO4 CO2 2 ++ 5 H5 H22O + 13 NO + 13 N22
((HHRR = - 3723 kJ) = - 3723 kJ)
HH22 + ½ O + ½ O22 →→ H H22O (O (HHRR = - 242 kJ) = - 242 kJ)
Butane, Nitrous oxide and piezo ignition…
Reactants Product Reactants Product HHRR (kJ) (kJ)
HH22 + 0,5 O + 0,5 O22 →→ HH22OO - 242- 242
HH2 2 + Cl+ Cl22 →→ HCl HCl - 185- 185
HH2 2 + N+ N22O O →→ HH22O + NO + N22 - 324- 324
NHNH33+ 0,75 O+ 0,75 O22 →→ 1,5 H1,5 H22O + 0,5 NO + 0,5 N22 - 317- 317
NHNH33+ 1,5 N+ 1,5 N22O O →→ 1,5 H1,5 H22O + 2 NO + 2 N22 - 440- 440
CO + 0,5 OCO + 0,5 O22 →→ COCO22 - 283- 283
CO + NCO + N22OO →→ COCO2 2 + N+ N22 - 365- 365
Stoichiometric Mixtures
Reactants Reactants Product Product HHRR (kJ) (kJ)
CHCH44 + 2 O + 2 O22 →→ COCO22 ++ 2 H2 H22OO - 802 - 802
CHCH4 4 + 4 N+ 4 N22O O →→ COCO2 2 ++ 2 H2 H22O + 4 NO + 4 N22 -1130 -1130
CC22HH2 2 + 2,5 O+ 2,5 O22 →→ COCO2 2 + H+ H22O O -1255 -1255
CC22HH2 2 + 5 N+ 5 N22O O →→ 2 CO2 CO2 2 + H+ H22O + 5 NO + 5 N22 -1666-1666
CC44HH10 10 + 6,5 O+ 6,5 O22 →→ 4 CO4 CO2 2 + 5 H+ 5 H22O O -2657-2657
CC44HH10 10 + 13 N+ 13 N22O O →→ 4 CO4 CO2 2 + 5 H+ 5 H22O + 13 NO + 13 N22 -3723 -3723
Stoichiometric Mixtures
ZIPPO boiling range: 113-133 °C (mainly octane)
octane: LEL: 0,8 %vol, HEL: 6,5 %vol
Vapour pressure of octane: 0,0147 bar
11 C C88HH1818 + 12,5 O + 12,5 O22
→ → 8 CO8 CO2 2 + 9 H + 9 H22OO
v.o.
Lighter fuel in a Fuji film can
Japanese devices…
PbZrxTiyO3
lead-titanate-zirconateceramics
ZIPPO-Explosion limit in a Fuji-film can
v.o.
Volume of the film can = 33 cmVolume of the film can = 33 cm33
Air pressure = 1 barAir pressure = 1 bar
78 % N78 % N22
(partial pressure = 0,78 bar)(partial pressure = 0,78 bar)Partial volume = 33cmPartial volume = 33cm33 x 0,78 x 0,78
21 % O21 % O22
(partial pressure = 0,21 bar)(partial pressure = 0,21 bar)partial volume = 33cmpartial volume = 33cm33 x 0,21 = x 0,21 =
6,9 cm6,9 cm33
OCTANE Explosion Limit in a Film Can
v.o.
pp(OCTAN)(OCTAN) = 0,0147 bar = 0,0147 barPP(AIR)(AIR) = 1,00 bar = 1,00 barpp(TOTAL)(TOTAL) = 1,0047 bar = 1,0047 bar
x: 0,0147 = 33 : 1,0147 x: 0,0147 = 33 : 1,0147 x =x = 0,5 cm0,5 cm33 0,5 cm0,5 cm33 CC88HH1818 : 6,9 cm: 6,9 cm3 3 OO22 = 1 : 14 = 1 : 14
33 : 100 = 0,5 : x 33 : 100 = 0,5 : x x = 1,5 Vol%x = 1,5 Vol%
Vol O2 = 6,9 cm3
Vol C8H18 = x cm3
V.O.
MANY THANKS TOMANY THANKS TO KAZUKO AND HIROSHI OGINOKAZUKO AND HIROSHI OGINO
FOR THE VERY FRIENDLY HOSPITALITY AND FOR THE VERY FRIENDLY HOSPITALITY AND HELPHELP
ACKNOWLEDGEMENTSACKNOWLEDGEMENTS
Many thanks Many thanks for your for your
interestinterest