Types of Reactions Chemistry Types of Reactions Chemistry.

63
Types of Types of Reactions Reactions Chemistry Chemistry

Transcript of Types of Reactions Chemistry Types of Reactions Chemistry.

Page 1: Types of Reactions Chemistry Types of Reactions Chemistry.

Types of ReactionsTypes of ReactionsChemistryChemistry

Page 2: Types of Reactions Chemistry Types of Reactions Chemistry.

Learning Objective

TLW identify and quantify changes that occur during chemical reactions (TEKS 8)

Page 3: Types of Reactions Chemistry Types of Reactions Chemistry.

Agenda

Review of Basics Define Types of Chemical Reactions and

Real-World Examples Examples of the Types of Chemical

Reactions Group Practice Individual Practice Labs

Page 4: Types of Reactions Chemistry Types of Reactions Chemistry.

Chemical Reactions –General Stuff

Reactants are added together to make products

Reactants are found on left side of chemical equation and products are on the right side

Compounds are formed – substances made up of two or more elements that chemically combined (not easily separated or impossible to return to original element)

Page 5: Types of Reactions Chemistry Types of Reactions Chemistry.

Chemical Reactions –General Stuff

Valence electrons and periodic trends determine how various atoms of elements react (or don’t react)

Catalysts are “outside agents” that may be added to speed up reactions or cause reactions to perform differently under different conditions (such as varying temperatures).– They are not used up in the reaction

Page 6: Types of Reactions Chemistry Types of Reactions Chemistry.

Chemical Reactions –General Stuff

Don’t forget about the laws of conservation of mass and energy… neither can be created nor destroyed– Reactants are transformed– Products are formed– Chemical energy converts to heat, light,

electricity, sound

Page 7: Types of Reactions Chemistry Types of Reactions Chemistry.

Chemical Reactions –General Stuff

Also – Law of Definite Proportions, which states in any sample of a chemical compound the elements are always combined in the same proportion by mass

H2O

H = 1 g x 2 = 2 g

O = 16 g

Total 18 g

H = 2 g / 18 g = 11% O = 16 g / 18 g = 89%

Page 8: Types of Reactions Chemistry Types of Reactions Chemistry.

Chemical Reactions –General Stuff

From Dalton’s Laws (remember him?) Law of Multiple Proportions states

whenever two elements form more than one compound different masses of one element that combine with the same mass of the other element are in the ratio of small whole number

H2O H2O2

Page 9: Types of Reactions Chemistry Types of Reactions Chemistry.

Chemical Reactions –General Stuff

Law of Definite Proportions – describes composition of one compound

Law of Multiple Proportions – compares composition of two different compounds containing same elements

Page 10: Types of Reactions Chemistry Types of Reactions Chemistry.

Types of Reactions Combination Combination (a.k.a. Synthesis, Addition)(a.k.a. Synthesis, Addition) DecompositionDecomposition Single Replacement Single Replacement (a.k.a. Single Displacement)(a.k.a. Single Displacement) Double Replacement Double Replacement (a.k.a. Double (a.k.a. Double

Displacement)Displacement) CombustionCombustion NeutralizationNeutralization PrecipitationPrecipitation Reduction/Oxidation Reactions (Reduction/Oxidation Reactions (RedoxRedox)) Energy Producing – Exothermic, Endothermic, Energy Producing – Exothermic, Endothermic,

LightLight

Page 11: Types of Reactions Chemistry Types of Reactions Chemistry.

CombinationCombination(aka Synthesis, Addition)(aka Synthesis, Addition)

Two or more elements or substances combine Two or more elements or substances combine to form a new compound. to form a new compound.

A + B A + B AB AB Examples –Examples –

– Formation of rustFormation of rust– Air pollutant sulfur dioxideAir pollutant sulfur dioxide– Polymerization (plastics)Polymerization (plastics)– PhotoPhotosynthesissynthesis (plants) (plants)

Page 12: Types of Reactions Chemistry Types of Reactions Chemistry.

CombinationCombination A + B A + B AB AB Where A and B are elements Where A and B are elements

and AB is a compound and AB is a compound Note that only one compound Note that only one compound

exists on the exists on the RIGHTRIGHT SIDE… SIDE…

Page 13: Types of Reactions Chemistry Types of Reactions Chemistry.

CombinationCombination

4Fe(s) + 3O4Fe(s) + 3O22(g) (g) 2Fe 2Fe22OO33(s)(s) S(s) + OS(s) + O22(g) (g) SO SOxx(g)(g) 2Na + Cl2Na + Cl22 2NaCl 2NaCl

ExamplesExamples

Page 14: Types of Reactions Chemistry Types of Reactions Chemistry.

Teacher Demo – need a better one…..

Page 15: Types of Reactions Chemistry Types of Reactions Chemistry.

DecompositionDecomposition

A single compound is broken down A single compound is broken down to produce two or more smaller to produce two or more smaller compounds and/or elements.compounds and/or elements.

AB AB A + B A + B Example – Example –

– Water with electricity into Water with electricity into hydrogen and oxygen (electrolysis)hydrogen and oxygen (electrolysis)

– Baking soda with heatBaking soda with heat

Page 16: Types of Reactions Chemistry Types of Reactions Chemistry.

DecompositionDecomposition

AB AB A + B A + B Where AB is a compound and Where AB is a compound and

A & B are elements or other A & B are elements or other compoundscompounds

Note that only one compound Note that only one compound exists on the exists on the LEFTLEFT SIDE… SIDE…

Page 17: Types of Reactions Chemistry Types of Reactions Chemistry.

DecompositionDecomposition

Examples:Examples:

2H2H22OO(l)(l) 2H 2H2(g)2(g) + O + O2(g) 2(g)

NaHCONaHCO3(s)3(s) 2H 2H2(g)2(g) + NaCO + NaCO33heat

Page 18: Types of Reactions Chemistry Types of Reactions Chemistry.

Teacher demo – baking soda and heat

Page 19: Types of Reactions Chemistry Types of Reactions Chemistry.

Single ReplacementSingle Replacement(Single Displacement)(Single Displacement)

One element replaces (displaces) a similar One element replaces (displaces) a similar element in a compoundelement in a compound

Produces heat (is exothermic)Produces heat (is exothermic) A + BC A + BC AC + B AC + B Example – Example –

– If you place an iron nail into a beaker of If you place an iron nail into a beaker of copper (II) chloride you will begin to see copper (II) chloride you will begin to see reddish copper forming on the iron.reddish copper forming on the iron.

– Iron Iron replacesreplaces ( (displacesdisplaces)) copper in the copper in the solution and the copper falls out of solution solution and the copper falls out of solution as a metalas a metal

Page 20: Types of Reactions Chemistry Types of Reactions Chemistry.

Single ReplacementSingle Replacement A + BC A + BC AC + B AC + B Where A and B are elements and BC Where A and B are elements and BC

and AC are compoundsand AC are compounds Can have more than 2 reactants and/or Can have more than 2 reactants and/or

productsproducts

Example: Example: 2HCl2HCl(l)(l) + Zn + Zn(s)(s) ZnCl ZnCl2(l)2(l) + H + H2(g)2(g)

FeFe(s) (s) + CuCl + CuCl2(l)2(l) Cu Cu(s)(s) + FeCl + FeCl2(l)2(l)

Page 21: Types of Reactions Chemistry Types of Reactions Chemistry.

Single ReplacementSingle Replacement All single replacement reactions are All single replacement reactions are

exothermicexothermic They give off heat and occur rapidlyThey give off heat and occur rapidly

Page 22: Types of Reactions Chemistry Types of Reactions Chemistry.

Teacher demo – Zinc plus hydrochloric acid or iron nail in copper(II)chloride

Page 23: Types of Reactions Chemistry Types of Reactions Chemistry.

Double ReplacementDouble Replacement(Double Displacement)(Double Displacement)

Ions from two compounds in solution exchange Ions from two compounds in solution exchange to produce two new compoundsto produce two new compounds

AB + CD AB + CD AD + CB AD + CB One compound usually forms a precipitate that One compound usually forms a precipitate that

settles out of the solution, a gas that bubbles settles out of the solution, a gas that bubbles out, or a molecular compound like waterout, or a molecular compound like water

The other compound formed often remains The other compound formed often remains dissolved in the solutiondissolved in the solution

Examples – Examples – – Baking soda and vinegarBaking soda and vinegar– Dried fruitDried fruit

Page 24: Types of Reactions Chemistry Types of Reactions Chemistry.

Double ReplacementDouble Replacement AB + CD AB + CD AD + CB AD + CB Where AB, CD, AD, & CB are all Where AB, CD, AD, & CB are all

compoundscompounds Can have more than 2 reactants and/or Can have more than 2 reactants and/or

productsproducts Examples:Examples: 2HCl + 2NaOH 2HCl + 2NaOH 2NaCl + 2H2NaCl + 2H22OO

NaNa22SOSO3(aq)3(aq) + 2HCl + 2HCl(aq)(aq)

2NaCl2NaCl(aq)(aq) + H + H22OO(l)(l) + SO + SO2(g)2(g)

Page 25: Types of Reactions Chemistry Types of Reactions Chemistry.

Teacher demo – the ever popular baking soda and vinegar or cleaning pennies with vinegar using salt as a catalyst

Page 26: Types of Reactions Chemistry Types of Reactions Chemistry.

CombustionCombustionCarbon substances combine with oxygen, Carbon substances combine with oxygen, releasing large amounts of energy, in releasing large amounts of energy, in the form of heat, light, etc. Carbon the form of heat, light, etc. Carbon dioxide and water are also typical dioxide and water are also typical productsproducts

CCxxHHyy + O + O22 CO CO22 + H + H22OO

Examples –Examples –– Natural gas to heat a houseNatural gas to heat a house– Hydrogen powered carsHydrogen powered cars

Page 27: Types of Reactions Chemistry Types of Reactions Chemistry.

General FormulaGeneral Formula

CCxxHHyy + O + O22 CO CO22 + H + H22OOhydrocarbon oxygen carbon waterhydrocarbon oxygen carbon water

dioxidedioxide

Examples -Examples -

CHCH4 4 + 2O+ 2O22 COCO22 + 2H + 2H22OO

2H2H22(g) + O(g) + O22(g) (g) 2H 2H22O(l)O(l)

Page 28: Types of Reactions Chemistry Types of Reactions Chemistry.
Page 29: Types of Reactions Chemistry Types of Reactions Chemistry.

Teacher demo – lighting a match

Page 30: Types of Reactions Chemistry Types of Reactions Chemistry.

NeutralizationNeutralization Double Replacement Reaction where wn acid

and a base react to form water and a salt General formula

HA + BOH H2O + BA acid base water salt

Examples –

HCl(aq) + NaOH(s) H2O(l) + NaCl(s)

H2SO4(aq) + Ca(OH)2(aq) H2O(l) + CaSO4(s)

Page 31: Types of Reactions Chemistry Types of Reactions Chemistry.

PrecipitationPrecipitation When solutions are saturated, adding

additional ions will cause a precipitate to form Solid – usually sinks to bottom, but can float Solubility product (Ksp) can be used to predict

formation of precipitates– If ion-product concentration > Ksp then a precipitate

will form

– If ion-product concentration < Ksp then a precipitate will not form

Page 32: Types of Reactions Chemistry Types of Reactions Chemistry.

Teacher demo – baking soda and vinegar… again (how boring)

Page 33: Types of Reactions Chemistry Types of Reactions Chemistry.

Practice Worksheet – Identify 5 basic reactions

Page 34: Types of Reactions Chemistry Types of Reactions Chemistry.

Discovery Video - ElectrochemistryReduction/Oxidation Reactions

A. Reaction in which electrons are transferredB. Commonly called the redox reactionC. One element is reduced – it gains electrons

One element is oxidized – it loses electrons

Reduction/OxidationReduction/Oxidation

Page 35: Types of Reactions Chemistry Types of Reactions Chemistry.

Redox reactions have radicals fragments of molecules with at least one electron for bonding

Ex. of radicals = Styrofoam

Page 36: Types of Reactions Chemistry Types of Reactions Chemistry.

Example of redox reactionRust = iron reacts with oxygen

Fe2O3

Fe loses 3 electronsO gains 2 electrons

Page 37: Types of Reactions Chemistry Types of Reactions Chemistry.

Rules for Assigning Oxidation Numbers

Page 38: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 1

The oxidation number of any uncombined element is 0

Page 39: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of Na (s) is 0.

Page 40: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 2

The oxidation number of a monatomic ion equals the charge on the ion.

Page 41: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of Cl- is -1.

Page 42: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 3

The more electronegative element in a binary compound is assigned the number equal to the charge it would have if it were an ion.

Page 43: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of O in NO is -2.

Page 44: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 4

The oxidation number of fluorine in a compound is always -1.

Page 45: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of F in LiF is -1.

Page 46: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 5

Oxygen has an oxidation number of -2 unless it is combined with F, when it is +2, or it is in a peroxide, such as H2O2, when it is -1.

Page 47: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of O in NO2 is -2.

Page 48: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 6

The oxidation state of hydrogen in most of its compounds is +1 unless it is combined with a metal, in which case it is -1.

Page 49: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of H in LiH is -1.

Page 50: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 7

In compounds, Group 1 and 2 elements and aluminum have oxidation numbers of +1, +2, and +3, respectively.

Page 51: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of Ca in CaCO3 is +2.

Page 52: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 8

The sum of the oxidation numbers of all atoms in a neutral compound is 0.

Page 53: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of

C in CCO3 is +4.

Page 54: Types of Reactions Chemistry Types of Reactions Chemistry.

Rule 9

The sum of the oxidation numbers of all atoms in a polyatomic ion equals the charge of the ion.

Page 55: Types of Reactions Chemistry Types of Reactions Chemistry.

Example:

The oxidation number of P in H2PO- 4 is +5.

Page 56: Types of Reactions Chemistry Types of Reactions Chemistry.

Exothermic Reactions

In many reactions, less energy is required to break the bonds in the reactants than is released when bonds form to make new products

In these reactions some type of heat or light is released and they are called exothermic

Exothermic reactions can be detected by a rise in temperature

Page 57: Types of Reactions Chemistry Types of Reactions Chemistry.

Exothermic Reactions

What are examples of exothermic reactions you are familiar with?

Demonstration

Page 58: Types of Reactions Chemistry Types of Reactions Chemistry.

Endothermic Reactions

Sometimes more energy is required to break bonds in the reactants than is released to form new products

The are called endothermic reactions You can detect these reactions by a

decrease in temperature

Page 59: Types of Reactions Chemistry Types of Reactions Chemistry.

Endothermic Reactions

What are examples of endothermic reactions you are familiar with?

Demonstration

Page 60: Types of Reactions Chemistry Types of Reactions Chemistry.

Group Practice ~ Name Those Reactions

Page 61: Types of Reactions Chemistry Types of Reactions Chemistry.

A Group Activity

Types of Chemical Reactions – Sorting Matslink

Page 62: Types of Reactions Chemistry Types of Reactions Chemistry.

Individual Practice

Identifying Types of Reactions Worksheet link

Crossword Puzzle

Page 63: Types of Reactions Chemistry Types of Reactions Chemistry.

Looking Ahead Labs –

– Conservation of Mass– Types of Chemical Reactions– Empirical Formula Determination– Predicting the Amount of Product in a Reaction– Identifying Relationships between Reactants and

Products in a Reaction– Predicting the Products of a Reaction– Precipitation Reactions– Energetic Reactions – exothermic and endothermic

experiments– Qualitative and Quantitative Analysis

More on calculating definite proportions and multiple proportions