Presentation on theme: "Chemical Reactions reactants products"— Presentation transcript:
1 Chemical Reactions reactants products Balancing chemical equationsTypes of chemical reactions
2 How reactants are transformed into products? Reactants are transformed during chemical reactionsEnergy is required (absorbed) to break a chemical bondEnergy is released when a chemical bond forms
3 Balancing equations Obey law of conservation of matter Chemical equations have two parts: reactants and products
4 How to balance?The total number of atoms of each element should be the same on both sides of equationUse coefficients to balance equationsExample:2H2 + O2 2 H2O
5 Types of chemical reactions Single replacementDouble replacementDecompositionCombinationCombustion
6 Synthesis (Combination) Reactions Two or more substances combine to form anew compound.A + X AXReaction of elements with oxygen and sulfurReactions of metals with HalogensSynthesis Reactions with OxidesThere are others not covered here!
7 Decomposition Reactions A single compound undergoes a reaction thatproduces two or more simpler substancesAX A + XDecomposition of: Binary compounds 2H2O(l ) 2H2(g) + O2(g) Metal carbonates CaCO3(s) CaO(s) + CO2(g) Metal hydroxides Ca(OH)2(s) CaO(s) + H2O(g) Metal chlorates 2KClO3(s) 2KCl(s) + 3O2(g) Oxyacids H2CO3(aq) CO2(g) + H2O(l )
8 Decomposition Reactions SulfatesWith the exception of alkali metals and alkaline sulfates, all other metals are decomposed by heat to form a metal oxideNitratesAlkali metals decompose on heating to yield the nitrites and oxygen. All other metal nitrates are decomposed to nitrogen dioxide, oxygen, and the metal oxide on heating.
9 Single Replacement Reactions A + BX AX + BBX + Y BY + XReplacement of:Metals by another metalHydrogen in water by a metalHydrogen in an acid by a metalHalogens by more active halogens
10 The Activity Series of the Metals Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Chromium Iron Nickel Lead Hydrogen Bismuth Copper Mercury Silver Platinum GoldMetals can replace other metalsprovided that they are above themetal that they are trying toreplace.Metals above hydrogen canreplace hydrogen in acids.Metals from sodium upward canreplace hydrogen in water
11 Predict if these reactions will occur 3Mg AlCl322Al MgCl23Can magnesium replace aluminum?YES, magnesium is more reactive than aluminum.Activity SeriesAl MgCl2No reactionCan aluminum replace magnesium?NO, aluminum is less reactive than magnesium.Therefore, no reaction will occur.Activity SeriesOrder of reactantsDOES NOTdetermine howthey react.MgCl AlNo reactionThe question we must ask is can the single element replace its counterpart?metal replaces metal or nonmetal replaces nonmetal.
12 The Activity Series of the Halogens Fluorine Chlorine Bromine IodineHalogens can replace otherhalogens in compounds, providedthat they are above the halogenthat they are trying to replace.2NaCl(s) + F2(g) 2NaF(s) + Cl2(g)???MgCl2(s) + Br2(g) ???No Reaction
13 Single Replacement Reactions Single Replacement ReactionsSodium chloride solid reacts with fluorine gasNaCl(s) + F2(g) NaF(s) + Cl2(g)Note that fluorine replaces chlorine in the compoundAluminum metal reacts with aqueous copper (II) nitrateAl(s)+ Cu(NO3)2(aq) Cu(s) + Al(NO3)3(aq)222332
14 Double Replacement Reactions The ions of two compounds exchange places in anaqueous solution to form two new compounds.AX + BY AY + BXOne of the compounds formed is usually aprecipitate, an insoluble gas that bubbles out ofsolution, or a molecular compound, usually water.
15 Double Replacement Reactions Double Replacement ReactionsThink about it like “foil”ing in algebra, first and last ions go together + inside ions go togetherExample:AgNO3(aq) + NaCl(s) AgCl(s) + NaNO3(aq)Another example:K2SO4(aq) + Ba(NO3)2(aq) KNO3(aq) + BaSO4(s)2
16 Combustion ReactionsA substance combines with oxygen, releasing a largeamount of energy in the form of light and heat. Reactive elements combine with oxygenP4(s) + 5O2(g) P4O10(s)(This is also a synthesis reaction) The burning of natural gas, wood, gasolineC3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g)
17 Write a balanced chemical equation for the following combustion reactions: A. C5H12O2 CO H2O856B. C22H462O2 CO H2O674446C. C15H28O2 CO H2O221514
19 Predict if a reaction will occur when you combine aqueous solutions of iron (II) chloride with aqueous sodium carbonate solution.If the reaction does occur, write a balanced chemical equation showing it.(be sure to include phase notation)iron (II) chloride sodium carbonatesodium chloride+iron (II) carbonateFe2+Cl1-Na1+CO32-Fe2+Cl1-Na1+CO32-Cl2FeCO3Na2NaClFeCO3(aq)(ppt)Using a SOLUBILITY TABLE:sodium chloride is solubleiron (II) carbonate is insolubleBalanced chemical equationFeCl2Na2CO3NaClFeCO3(aq)(ppt)+2(aq)(aq)Complete Ionic EquationFe2+(aq) + 2Cl1-(aq) + 2Na1+(aq) + CO32-(aq) Na1+(aq) + 2Cl1-(aq) + FeCO3(s)
20 Solubility rules Soluble in water: sodium, potassium, and ammonium salts; acetates and nitratesHalides with the exception of halides of lead (II), silver(I), and mercury(I).Sulfates with the exception of sulfates of calcium, barium, lead (II) and strontium
21 Insoluble in waterPhosphates, carbonates and sulfides except sodium, potassium, ammonium salts, and calcium sulfideHydroxides except sodium, potassium, calcium, and barium hydroxides
22 Acid-Base reactions (neutralization reactions) Acid: any compound that produces hydrogen ions (H+), when added to water.Base: any substance that produces hydroxide ions (OH-), when added to water.HCl(aq) + Na(OH)(aq) NaCl(aq) + H2O(l)