View
220
Download
3
Category
Tags:
Preview:
Citation preview
Predicting Reactions
Presented byMr. Mark LangellaSTANYS 2006PWISTA.com11/7/06
PWISTA-Innovative
Programs for teachers
Company-looking to distribute equipment
Company -looking to help local
community schools
Teaching Center-Needs program
that science teachers
are looking to
attend
Teaching Center - not enough
teachers to run program
School District-needs to supply at least 15 hours
of teacher training
School District has no teaching center
Why do the reactions occur?
Gibbs Free Energy drives the Spontaneous reactionsLower PE energyFormation of Stronger BondsGreater Entropy ( Formation of Gases)
Solubility Formation Constant Lose Yourself in Chemical Reactions - Go
ogle Video
Synthesis or Combination Reactions In synthesis or combination reactions, two
or more substances combine together to form a single product.
The general form is A + B C The products must contain only those
elements found in the reactants.
Metal + Nonmetal Salt
Magnesium ribbon is burned in oxygen
Combination or Synthesis Reactions General form
A + B C
In this demonstration 2 Mg + O2 MgO
3 Mg + N2 Mg3N2
The oxygen and nitrogen occur naturally in the
atmosphere O2 is 21% of air N2 is 78% of air
Energy Two types of energy are produced in this
demonstration heat energy Hf MgO = -601.83 kJ/mole
(kiloJoules per mole) this is said to be the ‘heat of formation’ for MgO the negative sign indicates the formation is exothermic
light energy approximately 10% of the energy of combustion occurs
as light in this demonstration more light than any other known reaction
Online Demos
Reaction of Iron and Sulfur http://www.pc.chemie.uni-siegen.de/pci/versuche/pics/anim/fes.mpg Fe + S FeS Reaction of Potassium and Oxygen http://neon.chem.ox.ac.uk/vrchemistry/FilmStudio/alkalimetals/HTML/pag
e08.htm
Reaction of Lithium and Oxygen http://neon.chem.ox.ac.uk/vrchemistry/FilmStudio/alkalimetals/HTML/pag
e02.htm Reaction of Lithium and Chlorine http://neon.chem.ox.ac.uk/vrchemistry/FilmStudio/alkalimetals/HTML/pag
e04.htm Reaction of Sodium and Oxygen http://neon.chem.ox.ac.uk/vrchemistry/FilmStudio/alkalimetals/HTML/pag
e05.htm Reaction of Zinc and Sulfur http://boyles.sdsmt.edu/znsulf/zincsul.htm
Nonmetal + Nonmetal Molecular compounds Reaction of Hydrogen
and Oxygen http://www.chem.uiuc.
edu/clcwebsite/video/Bal2.mov
Rubber tubing
Volumetric flaskcontaining
NaOH and Al
Drying tube
Water bottleclamped onto
a rinstand
Short piece ofPyrex glass tubinginserted into aone-hole stopper
Reaction of Phosphorus and Chlorine
http://boyles.sdsmt.edu/pwithcl/DirksTwo.asx
P4(s) + 10 Cl2(g) 4 PCl5(s)
Oxidation Number Changes
Nonmetal Oxide + Water Oxyacid
Oxy Acid= Contains H+ ions attached to common Polyatomic ion of Nonmetal Oxide plus one more oxygen
Formation of Carbonic Acid
Carbon dioxide and Water- Carbon Dioxide is easily produced by the reaction of sodium bicarbonate and vinegar.
http://boyles.sdsmt.edu/respira/AlexanderCo2Blue.asx
Reaction of Carbon Dioxide and Limewater
http://boyles.sdsmt.edu/respira/Alexander
Co2White.asx
CO2(g) + Ca(OH)2(l) CaCO3(s) + H2O(l)
Metal oxide + water metal hydroxide
Egg Fry
DECOMPOSITION REACTIONS
Substances break down by means of decomposition reactions
The general form of a decomposition reaction is
C A + B Decomposition reactions are the opposite
of combination or synthesis reactions
Decomposition of Metal Carbonate
Heating a metal carbonate always yields the metal oxide and carbon dioxide. MCO3 MO + CO2
Heating the carbonates Most carbonates tend to decompose on heating to give the metal oxide and
carbon dioxde. For example, a typical Group 2 carbonate like calcium carbonate
decomposes like this: In Group 1, lithium carbonate behaves in the same way - producing lithium
oxide and carbon dioxide. The rest of the Group 1 carbonates don't decompose at Bunsen
temperatures, although at higher temperatures they will. The decomposition temperatures again increase as you go down the Group.
Metal Hydrogen Carbonate Decomposition Heating a metal bicarbonate gives the
metal oxide, carbon dioxide, and water. MHCO3 MO + H2O + CO2
Solid Sodium Hydrogen Carbonate is strongly heated
Metal Chlorate Decomposition
Heating a metal chlorate gives the metal chloride plus oxygen.
MClO3 MCl + O2
Burning Gummi Bears http://www.webct.com/service/ViewContent?
contentID=1249557&communityID=858&categoryID=1249537&sIndex=0
Logger Pro Analysis
Decomposition of Ammonium Dichromate http://boyles.sdsmt.edu/dichrom/Ammoniu
mDichromate.asx
(NH4)2Cr2O7(s) Cr2O3(s) + N2(g) + 4H2O(g)
Peroxide Decomposition
Elephant’s Toothpaste Website: http://boyles.sdsmt.edu/tpaste/Cain.asx
Genie in a Bottle Demo Website: http://
boyles.sdsmt.edu/geniebot/genie.htm
Reactions Based on Reduction Potentials EMF Potential
Reduction and OxidationSingle replacement
Cation Replacement
There are two types of single replacement reactions, in one, a metal or hydrogen replaces a positive ion
M0 + A+B- M+B- + A0
Reaction of Sodium and Water
http://boyles.sdsmt.edu/sodwat/SodiumWater.asx
http://www.theodoregray.com/PeriodicTable/Stories/011.2/Videos/SodiumResearch03.html
http://www.theodoregray.com/PeriodicTable/Stories/011.2/Videos/SodiumResearch02.html
Sodium(s) + Water(l) Sodium Hydroxide(aq) + Hydrogen(g)
2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)
Reaction of Potassium and Water http://www.chem.shef.ac.uk/webelements-moov/K_H2O.mov http://www.theodoregray.com/PeriodicTable/AlkaliBangs/
019_K_doghowls.html Potassium(s) + Water(l) Potassium Hydroxide(aq) +
Hydrogen(g) 2K(s) + 2H2O 2KOH + H2(g) Group I with water video http://video.google.com/videoplay?docid=-213426665480139
2897&q=rubidium+water
Reaction of Zinc and Tin (II) Chloride
http://www.chemtopics.com/lectures/unit02/lecture1/displace.htm
Zinc(s) + Tin (II) Chloride(aq) Tin(s) + Zinc (II) Chloride(aq)
Zn(s) + SnCl2(aq) Sn(s) + ZnCl2(aq) Zinc(s) + Hydrochloric Acid(aq) Zinc (II)
Chloride(aq) + H2(g) Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g) Aluminum and Copper ( II) Chloride
Thermite Reaction 2Al(s)+Fe2O3(s) Al2O3(s)+2Fe(l)
http://boyles.sdsmt.edu/thermite/ThirstrupThermiteClose.asx
http://www2.chemie.uni-erlangen.de/education/medprak/videos/thermit_v.mpg
http://video.google.com/videoplay?docid=-7231843493488769585&q=Reactions&hl=en
Aqueous Redox ReactionsOxidation States of Manganese
Procedure Add 30 ml of a .01 M KMnO4 solution to four small flasks
labeled A , B, N ( Place Tablet 1/10 ml water) To Flask A, Add 10 ml of 3M H2SO4
MnO4- + H+ To Flask B, add 10 ml of 5 M NaOH. MnO4- + OH- To Flask N add nothing. MnO4-
Watch the color changes
To Flask A add .01M NaHSO3 ( Tablet 2) slowly till you get a colorless Mn2+ ion.
MnO4- + 5H++ HSO3
- 3H2O + 2Mn2+ + 5SO42-
To Flask N add .01M NaHSO3 ( Tablet 2)until a brown precipitate forms.
2MnO4- + 3HSO3
- 3SO42- + H++ H2O +MnO2
To Flask B slowly add .01M NaHSO3 ( Tablet 2) until a green solution forms.
2MnO4- + OH-+ HSO3
- 2MnO42- + 2H2O + SO4
2-
The Amazing Purple Drop
Oil Drop Demo I2 + H20 HOI ( aq) + HI ( aq)
Meanwhile I2 + 2e- = 2I-, Eo = 0.54 v
HCHO + 2H+ + 2e- = CH3OH, Eo = 0.19 v
Reactions Driven by
Solubility and Precipitation Formation of Gases ( Increase in entropy) Formation of Water Coordinate Covalent Bond Formation
( Lewis Acid-Base) Formation Constants
Formation of Water
Metal Oxide + an Acid Salt + Water Metal Hydroxide + an Acid Salt + Water (a special type of reaction called
neutralization) Milk of Magnesia Demo
PREDICTIONS BASED ON SOLUBILITY If one or both of the products in the double replacement
reaction is insoluble in water, the reaction will occur. Reaction #1 Lead Nitrate and Sodium Chromate Pb(NO3)2 (aq) + Na2CrO4 (aq) PbCrO4 (s) +
Na NO3(aq) Pb 2+ + CrO42- PbCrO4 (s) Reaction # 2 Silver Nitrate and Hydrochloric Acid AgNO3(aq) + HCl(aq) AgCl (s) + HNO3 (aq)
SOLUBILITY RULES FOR COMMON IONIC COMPOUNDS IN WATER
1. All nitrates, chlorates, and acetates are soluble in water. Silver acetate is sparingly soluble.
2. Most common acids are soluble in water. 3. All common IA, and ammonium compounds are soluble in water. 4. All chlorides, bromides, and iodides are soluble in water except
silver, mercury (I), and lead. HgI2 and HgBr2 are insoluble in water. 5. All sulfates are soluble in water except CaSO4, SrSO4, BaSO4,
PbSO4, Hg2SO4. Ag2SO4 is sparingly soluble in water. 6. All carbonates, phosphates, oxides, and sulfites are insoluble in
water but soluble in dilute acids except the IA and ammonium compounds. 7. The sulfides of all metals are insoluble in water except the IA, IIA,
and ammonium sulfides. 8. All hydroxides are insoluble in water except the IA, Ca(OH)2,
Sr(OH)2, and Ba(OH)2 hydroxides.
Combustion
Whoosh Bottle Rocket Explosions Dynamite Soap Mixtures Repeating Exploding Flask
Recommended