Chemical Reactions – Part IIFive Types of Chemical Reactions

Unit 7: Stoichiometry - Part IVMrs. Callender

Lesson Essential Question

What are the five general types of chemical reactions?

Five Basic Reaction Types

Combination or Synthesis

Two or more substances combine to form a new compound.

A + X AX

Iron Wool added to Sulfur with heat yields Iron (II) Sulfide.

Fe(s) + S(s)

FeS(s)

Iron + Sulfur

Singing Test Tube

Examples of Synthesis Reactions

1. Reactions of metals with oxygen.Magnesium(s) + Oxygen(g)2 Mg(s) + O2(g) 2 MgO(S)

Magnesium Oxide 2. Reactions of metals with halogens.

Aluminum(s) + Bromine(l) 2 Al(s) + 3 Br2(l) 2 AlBr3(S)

Aluminum Bromide

3. Reactions of metals with sulfur.Silver(s) + Sulfur(s) Ag(s) + S(s) Ag2S(S)

Silver Sulfide

Decomposition

A single compound undergoes a reaction a produces two or more substances.

A X A + X

Potassium Chlorate is decomposed by heating forming potassium chloride and oxygen gas.

KClO3(s) KCl(s) + O2(g)

Decomposition of Sugar

Exploding Gummy Bear

Examples of Decomposition Reactions

1. Decomposition of Binary Compounds.

2. Decomposition of Metal Carbonates.

3. Decomposition of Metal Hydroxides (Bases)

2 MgO(s) 2 Mg(s) + O2(g)

Magnesium + Oxygen

Magnesium Oxide(s)

Aluminum Carbonate(s)Al2(CO3)3(S) Al2O3(s) + 3 CO2(g)

Aluminum Oxide + Carbon

Dioxide

Magnesium Hydroxide(s) Mg(OH)2(s) MgO(S) +

H2O(g)

Magnesium Oxide(s)

+Water Vapor(g)

Decomposes into two separate elements.

Decomposes into metal oxide and CO2(g)

Decomposes into metal oxide (basic anhydride) and H2O

Examples of Decomposition Reactions

4. Decomposition of Metal Chlorates.

5. Decomposition of Ternary Acids.

Sodium Chlorate(s)

Sulfuric Acid(l)

2 NaClO3(s) 2 NaCl(s) + 3 O2(g)

sodium chloride + OxygenH2SO4(l) SO3(g) + H2O(l)

Sulfur Trioxide + Water

Decomposes to produce metal chloride and oxygen gas.

Decomposes to produce Nonmetal Oxide (Acidic Anhydride) and water.Since the nonmetals in the ternary acid usually have multiple charges you must work backwards to find its charge.

H2SO4

4(-2)-82(+1)+2+ X

+= +6

Use this charge to form the acidic anhydride (nonmetal oxide) formula.

SO+6 -2SO3

3(-2)

Lets try some examples…

1. Na(s) + O2(g) SYNTHESISNa2O(s)

4 2

2. MgCO3(S) DecompositionMgO(s) + CO2(g)

3. Fe(III)(s) + Br2(l) SYNTHESIS

FeBr3(s)2 3 2

What’s wrong with the equation below?2H3PO4(l) 2PO2(g) + 3 H2O(l)

2H3PO4(l) 2P2O5(g) + 3 H2O(l)

Part II of Reactions

Single Replacement or Single Displacement

One element displaces another element when higher on the activity chart. A + BX B + AX

Copper penny added to silver nitrate produces silver metal and blue aqueous copper (II) nitrate.

Cu(s) + AgNO3(aq) Ag(s) + Cu(NO3)2(aq)

BX + Y B + YX

How to Make Silver

Examples of Single Displacement Reactions

1. Replacement of metal by another metal.

2. Replacement of hydrogen in water by a metal.

Copper(s) + Silver Nitrate(aq)

Zinc(s) + Water(l)Zn(s) + 2 HOH(l) Zn(OH)2(aq) + H2(g)

Zinc Hydroxide + Hydrogen

gas

Cu(II)(s) + 2AgNO3(aq) 2Ag(s) + Cu(NO3)2(aq)

Silver + Copper (II) Nitrate

3. Replacement of hydrogen in an acid by a metal.

Magnesium(s) + Hydrochloric Acid(l)Mg(s) + 2 HCl(l) MgCl2(aq) + H2(g)

Examples of Single Displacement Reactions

4. Replacement of halogens by another halogen.Chlorine(g) + Sodium Bromide(s)Cl2(g) + 2 NaBr(s) Br2(l) + 2 NaCl(s)

Bromine + Sodium Chloride

Activity SeriesLithiumPotassium CalciumSodiumMagnesium AluminumZincChromiumIronNickelLead HydrogenBismuthCopperMercurySilverPlatinumGold

1. Metals can displace other metals provided that they are above the metal they are trying to displace.

2. Metals above hydrogen can displace hydrogen from an acid.

3. Metals from sodium upward can replace hydrogen from water.

Activity SeriesFluorineChlorineBromineIodine

1. Halogens can replace other halogens provided they are higher than the halogen they are trying to replace.

2 NaCl(s) + F2(g) 2 NaF(s) + Cl2(g)

NaF(s) + Cl2(g) No Reaction

Double Replacement or Double Displacement

The ions of two compounds switch places in an aqueous solution to form two new compounds. AY + BX BY + AX

Lead (II) Nitrate added to Potassium Iodide produces a Lead (II) Iodide ppt. and aqueous Potassium Nitrate solution.

Pb(NO3)2(aq) + KI(aq) PbI2(s) + KNO3(aq)

One of the products is usually an insoluble gas that bubbles out of the solution, a precipitate, or a molecular compound, usually water.

Double Displacement Reaction

Golden Rain

Examples of Double Displacement Reactions

1. Copper (II)Sulfate(aq) + Lead (II) Nitrate(aq)

2. Zinc Hydroxide(aq) + Sodium Bromide(aq)2. Zn(OH)2(aq) +2 NaBr(aq) ZnBr2(aq) + 2NaOH(aq)

Zinc Bromide +

Sodium Hydroxide

1. CuSO4( (II)aq) + Pb(NO3)2(aq) PbSO4(s) + Cu(NO3)2(aq)

Lead (II) Sulfate + Copper (II) Nitrate

Precipitate

Combustion ReactionsA substance combines with oxygen producing a large amount of energy in the form of heat or light.

P4(s) + 5 O2(g) P4O10(s)

The burning of organic materials in general. C3H8(g) + 5 O2(g) 3 CO2(g) + 4 H2O(l) + Energy

This is also a synthesis reaction.

Reactive elements combine with oxygen.

Combustion of Ethanol