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Warm Up
Watch the Demo of Copper with Nitric Acid. List several evidences for chemical reaction.
state_in_eqn.exe04m11vd4.mov
Chemical reactions are everywhere!
Chemical Reactions: the process by which the atoms of one or more substances are rearranged to form different substances.
Atoms are rearranged during the flash of lightning!
Chemical Equations
Reactants Products
Reactants: starting substances
Products: substances formed during the reaction
*Shows the direction in which the reaction progresses.
* means “yield” or “react to produce”
Chemical Equations
Symbols are used to show the physical states: solid(s), liquid(l), gas(g).
“aqueous” (aq) substance is dissolved in water
The Language of ChemistryWrite the chemical equation that corresponds to
the following reactions
Example
1. Solid calcium oxide reacts with water and yields calcium hydroxide solution.
2. Zinc metal reacts with a hydrogen sulfate solution to produce a zinc sulfate solution and hydrogen gas.
3. A potassium bromide solution reacts with chlorine gas to produce a potassium chloride solution and bromine gas.
Balancing Equations
Coefficient – the whole number out front of the formula- tells you how many of each molecule
Subscript – small number to the bottom right of an element- tells you how many atoms of that element are in the molecule.
Balancing Chemical Equations
1. Write a formula equation with correct symbols and formulas.
2. Count the number of atoms of each element on each side of the arrow.
3. Balance atoms by using coefficients.
4. Check your work by counting atoms of each element.
Balancing Chemical Equations
Practice Problems Sodium hydroxide decomposes to
produce sodium oxide and water.
Iron reacts with oxygen to produce iron(III) oxide.
Warm Up
Write a balanced chemical equation for the following demo.
Isopropyl alcohol (CH3)2CHOH when ignited (Oxygen gas) combusts to form Carbon dioxide gas and water.
Observing and Predicting ReactionsObserving and Predicting Reactions
How do we know whether a reaction occurs? What clues does nature offer? Make a list.
What clues does nature offer that a chemical reaction occurred?What clues does nature offer that a chemical reaction occurred?
ppt crystal color gas fumes smoke temperature flames magnetic
soundlightsolid decompexplosionsolid dissol.odorelect. cond.pH changedensityelectricity Go to next topic
Moving On
Precipitate FormationPrecipitate Formation
Ag+ + Cl- AgCl Cr3+ + 3OH- Cr(OH)3
Ba2+ + CrO42- BaCrO4
return
BaCrO4.mov.lnk
04m12vd1.mov.lnk
Solid Decomposition
(NH4)2Cr2O7(s) Cr2O3(s) + 4H2O(g) + N2(g)
CuSOCuSO44..5H5H22OO
CuSOCuSO44 + 5H + 5H22O(g)O(g) 03m14vd1.mov.lnk
2NI2NI33 N22 + 3I + 3I22 Vd05_005.mov.lnk
Chmvid06.mov.lnk volcano.mov.lnk
return
Gas BubblesGas Bubbles
Ca + 2H2O Ca(OH)2 + H2(g) Cr + 2H+ Cr2+ + H2(g)
Mg + 2HCl MgCl2 + H2
tums.mov.lnk
04m05vd1.mov.lnk
return
Fumes/Gas Formation
Cu + 4HNO3 Cu(NO3)2 + 2NO2 + 2H2O
2H2O2 2H2O + O2
Zn + IZn + I2 2 ZnIZnI22
04m11vd4.mov.lnk Chmvid03.mov.lnkreturn
Smoke
2Al + 3Br2 2AlBr3 2Na + Cl2 2NaCl P4 + 5O2
P4O10
04m02vd1.mov.lnk
04m04vd1.mov.lnk
Vd05_004.mov.lnk
return
Flames
2Na + Cl2 2NaCl 2CrO3 + 3C2H5OH
Cr2O3 + 3CH3CHO + 3H2O
A04-2-20.mov.lnk return
Light
2Fe + 3O2 Fe2O3
2CH3OH + O2 2CO2 + 4H2O
2H2H22 + O + O22 2H2O05m04vd1.mov.lnk
04m18vd2.mov.lnk
return
Temperature ChangeTemperature Change
Ba(OH)2.8H2O + NH4Cl
Thermite: Al + Fe2O3
Chmvid13.mov.lnk return
Color ChangeColor Change
Cl2 + 2I- 2Cl- + I2 Cu + 4HNO3
Cu(NO3)2 + 2NO2 + 2H2O
04m11vd4.mov.lnk
return
Crystal Formation/Solid DepositionCrystal Formation/Solid DepositionCrystal Formation/Solid DepositionCrystal Formation/Solid Deposition
Cu + 2Ag+ Cu2+ + 2Ag
Zn + Sn2+ Zn2+ + SnZn_sncl2.mov.lnk
04m16vd1.mov.lnk
return
Solid DissolutionMg(OH)2 + 2HCl MgCl2 + 2H2O
AgCl(s) + 2NHAgCl(s) + 2NH33(aq) (aq)
Ag(NHAg(NH33))22+ + + Cl+ Cl--
return
Sound
Oxidation of sugar
Fireworks
bang.mov.lnk
06m02vd1.mov.lnk
return
Explosion
Dynamite
Building DemolitionBuilding Demolition Whale RemovalWhale Removalreturn
Odor
Certain molecules, especially those containing sulfur or nitrogen, have distinctive odors.
return
Electrical Conductivity
Ba(OH)Ba(OH)22 + H + H22SOSO44
return
Density/Volume
Sugar + H2SO4
volcano.mov.lnk
return
pH Change
return
Magnetic PropertiesFe + S8
return
Generate Electricity Chemical
reaction in the battery
returnreturn
Lab- How do we know what gas is being produced?
Demo- Gas Collection by Water Displacement
Minimum of two trials of each reaction Work as pairs within your groups
While others are testing draw apparatus and write the general procedures
Lab- How do we know what gas is being produced?
Experiment 1Zinc metal reacts with hydrochloric acid to
produce hydrogen gas and zinc (II) chloride.
Experiment 2Dihydrogen dioxide in the presence of the
catalyst sodium iodide decomposes to produce oxygen gas and liquid water.
Lab- How do we know what gas is being produced?
Experiment 3Calcium Carbonate reacts with hydrochloric acid to produce a
gas. What gas is it? Design an experiment to identify the gas produced.
Include predictions. Get it signed off before you begin
If…and…then… If(hypothesis) and(test) then(prediction) If all chemistry students have memorized the element
names and symbols and they are asked to the name or symbol for any element then every student will answer every question correctly.
Lab- How do we know what gas is being produced?
What did you learn from Experiment 3? What gas is being produced?
Lab- How do we know what gas is being produced?
Experiment 4
Can we confirm this some other way?
Group Quiz
1. Hydrogen gas reacts with oxygen gas to produce water
2. Carbon monoxide gas reacts with oxygen gas to yield carbon dioxide gas.
3. Liquid dihydrogen dioxide decomposes to produce water and oxygen gas.
4. A calcium hydroxide solution reacts with a hydrogen sulfate solution to produce a calcium sulfate solution and water.
What do all Chemical Reactions have in Common?
All Chemical Reactions obey the Law of Conservation of Matter
Nothing can be created or destroyed.
(What goes in must come out.)
4 main types of chemical reactions
Synthesis or Combination Decomposition Single Displacement Double Displacement
Types of Chemical Reactions
Combination reaction• A + B AB• Ex. metal + oxygen metal oxide
2 Mg (s) + O2 (g) 2 MgO (s)
Decomposition ReactionAB A + BEx. salt metal + nonmetal
2 NaCl (s) 2 Na (s) + Cl2 (g)
Single-Displacement ReactionA + BC B + AC or A + BC C + BA
Ex. metal + acid hydrogen + salt• Zn (s) + 2 HCl (aq) H2 (g) + ZnCl2 (aq)
Ex. metal + salt metal + salt• Fe (s) + CuSO4 (aq) Cu (s) + FeSO4 (aq)
• Double-Displacement ReactionAB + CD AD + CB
Ex. acid + base salt + water• HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l)
Can you Classify the following picture reactions?
1
2
3
4
4 Types of ReactionsSynthesis
Decomposition
Single Displacement
DoubleDisplacement
Some Practice
Write as many chemical reactions as you can think of using the following atoms and molecules as reactants.
Practice
Word Equations and reaction types identification
Classification of Chemical reactions
Individual Classify each type of reaction
Group Quiz Work as a group to write word equations
for each of the reactions
Classification of Chemical Reactions
Examples
1. 2H2 + O2 2H2O
Hydrogen reacts with oxygen to produce water.
2. 2H2O 2H2 + O2
Water decomposes to produce hydrogen and oxygen
Round Table – Balancing Chemical Equations
1. Balance the Equation
2. Write a complete sentence for each reaction including (atom/molecule) references to the coefficients.
Team
Iron can be obtained by reacting the naturally occurring ore hematite, Fe2O3, with carbon. The carbon is converted to CO2. Write a balanced chemical equation for this reaction.
Helpful info
Sulfuric Acid- H2SO4
Ammonia- NH3
Carbonic Acid - H2CO3
Hydrofluoric Acid – HF
Phosphoric Acid – H3PO4
Law of Conservation of Mass
Balancing synthesis and Decomposition Reactions Counting atom amu– atomic mass unit
Predicting Products
Identify the type of reaction Write the products of the reaction Balance the equation
Example.
1. Cl2 + KI
2. FeCl3 + NaOH
Single Displacement: Cu + AgNO3
Vd04_012.mov.lnk
Lab – Types of Reactions
9 experiments Work at an open station Demo Copper and Silver Nitrate
Predicting Products
Being able to write a chemical equation does not necessarily mean that the reaction will take place.
There is a way to predict whether a reaction will occur and what the products will be.
The Activity Series of Metals
Predicting Products Predicting Products The Activity SeriesThe Activity SeriesPredicting Products Predicting Products The Activity SeriesThe Activity Series
Matter tends to react in such a way that more reactive substances form less reactive substances.
Activity series: a list of metals organized according to their tendency to react.
Activity Series
The higher the metal on the activity series, the more active that metal.
The more active elements tend to be more stable in a compound than in elemental form
single_displ.exe.lnk
Predict whether a reaction occurs
Pb + MgCl2 Al + Cu(NO3)2
Practice
Group Quiz
Na + H2O
Ca + Fe(NO3)2
Ag + Mg(NO3)2
Zn + Cu(NO3)2
Objectives
Students will review types of chemical reactions.
Students will investigate the law of conservation of matter and its effect on chemical equations.
Students will learn to balance chemical equations