Chemical Reactions Chemistry 11 – Unit VI (p.114-118) :Chemical Reactions Chemistry 11 – Unit VI (p.114-118)


Types of Reactions :Types of Reactions There are five basic types of chemical reactions we will talk about: Synthesis reactions Decomposition reactions Single replacement / displacement reactions Double replacement / displacement reactions Combustion reactions You need to be able to identify the type of reaction and predict the product(s)


Steps to Writing Reactions :Steps to Writing Reactions Some steps for doing reactions Identify the type of reaction Predict the product(s) using the type of reaction as a model Balance it Don’t forget about the diatomic elements! (BrINClHOF) For example, Oxygen is O2 as an element. In a compound, it can’t be a diatomic element because it’s not an element anymore, it’s a compound!


1. Synthesis reactions :1. Synthesis reactions Synthesis reactions occur when two substances (generally elements) combine and form a compound. (Sometimes these are called combination or addition reactions.) reactant + reactant ? 1 product Basically: A + B ? AB Example: 2H2 + O2 ? 2H2O Example: C + O2 ? CO2


Synthesis Reactions :Synthesis Reactions Here is another example of a synthesis reaction


Practice :Practice Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas Na(s) + Cl2(g) ? Solid Magnesium reacts with fluorine gas Mg(s) + F2(g) ? Aluminum metal reacts with fluorine gas Al(s) + F2(g) ?


Practice :Practice Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas 2 Na(s) + Cl2(g) ? 2 NaCl(s) Solid Magnesium reacts with fluorine gas Mg(s) + F2(g) ? MgF(s) Aluminum metal reacts with fluorine gas 2 Al(s) + 3 F2(g) ? 2 AlF3(s)


2. Decomposition Reactions :2. Decomposition Reactions Decomposition reactions occur when a compound breaks up into the elements or in a few to simpler compounds 1 Reactant ? Product + Product In general: AB ? A + B Example: 2 H2O ? 2H2 + O2 Example: 2 HgO ? 2Hg + O2


Decomposition Reactions :Decomposition Reactions Another view of a decomposition reaction:


Decomposition Exceptions :Decomposition Exceptions Carbonates and chlorates are special case decomposition reactions that do not go to the elements. Carbonates (CO32-) decompose to carbon dioxide and a metal oxide Example: CaCO3 ? CO2 + CaO Chlorates (ClO3-) decompose to oxygen gas and a metal chloride Example: 2 Al(ClO3)3 ? 2 AlCl3 + 9 O2 There are other special cases, but we will not explore those in Chemistry 11


Practice :Practice Predict the products. Then, write and balance the following decomposition reaction equations: Solid Lead (IV) oxide decomposes PbO2(s) ? Aluminum nitride decomposes AlN(s) ?


Practice :Practice Predict the products. Then, write and balance the following decomposition reaction equations: Solid Lead (IV) oxide decomposes PbO2(s) ? Pb(s) + O2(g) Aluminum nitride decomposes 2AlN(s) ? 2Al(s) + N2(g)


Practice :Practice Identify the type of reaction for each of the following synthesis or decomposition reactions, and write the balanced equation: N2(g) + O2(g) ? BaCO3(s) ? Co(s)+ S(s) ? NH3(g) + H2CO3(aq) ? NI3(s) ? (make Co be +3) Nitrogen monoxide


Practice :Practice Identify the type of reaction for each of the following synthesis or decomposition reactions, and write the balanced equation: N2(g) + O2(g) ? 2NO(g) BaCO3(s) ? BaO(s) + CO2(g) 2Co(s)+ 3S(s) ? Co2S3(s) 2NI3(s) ? N2(g) + 3I2(g)


3. Single Replacement Reactions :3. Single Replacement Reactions Single Replacement Reactions occur when one element replaces another in a compound. A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-). element + compound? product + product A + BC ? AC + B (if A is a metal) OR A + BC ? BA + C (if A is a nonmetal) (remember the cation (+) always goes first!) When H2O splits into ions, it splits into H+ and OH- (not H+ and O-2 !!)


Single Replacement Reactions :Single Replacement Reactions Another view:


Single Replacement Reactions :Single Replacement Reactions Write and balance the following single replacement reaction equation: Zinc metal reacts with aqueous hydrochloric acid Zn(s) + HCl(aq) ? ZnCl2 + H2(g) Note: Zinc replaces the hydrogen ion in the reaction 2


Single Replacement Reactions :Single Replacement Reactions Sodium chloride solid reacts with fluorine gas NaCl(s) + F2(g) ? NaF(s) + Cl2(g) Note that fluorine replaces chlorine in the compound Aluminum metal reacts with aqueous copper (II) nitrate 2Al(s)+ 3 Cu(NO3)2(aq)? 2Al (NO3)3(aq) + 3Cu(s) 2 2


4. Double Replacement Reactions :4. Double Replacement Reactions Double Replacement Reactions occur when a metal replaces a metal in a compound and a nonmetal replaces a nonmetal in a compound Compound + compound ? product + product AB + CD ? AD + CB


Double Replacement Reactions :Double Replacement Reactions Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Example: AgNO3(aq) + NaCl(s) ? AgCl(s) + NaNO3(aq) Another example: K2SO4(aq) + Ba(NO3)2(aq) ? KNO3(aq) + BaSO4(s) 2


Practice :Practice Predict the products. Balance the equation HCl(aq) + AgNO3(aq) ? CaCl2(aq) + Na3PO4(aq) ? Pb(NO3)2(aq) + BaCl2(aq) ? FeCl3(aq) + NaOH(aq) ? H2SO4(aq) + NaOH(aq) ? KOH(aq) + CuSO4(aq) ?


Practice :Practice Predict the products. Balance the equation HCl(aq) + AgNO3(aq) ? HNO3(aq) + AgCl(s) 3CaCl2(aq) + 2Na3PO4(aq) ? Ca3(PO4)2(s) + 6NaCl(aq) Pb(NO3)2(aq) + BaCl2(aq) ? Ba(NO3)2(aq) + PbCl2(s) FeCl3(aq) + 3NaOH(aq) ? Fe(OH)3 (s) + 3NaCl(aq) H2SO4(aq) + 2NaOH(aq) ? Na2SO4(aq) + 2H2O(l) 2KOH(aq) + CuSO4(aq) ? K2SO4(aq) + Cu(OH)2(s)


. Hydrocarbon Combustion Reactions :. Hydrocarbon Combustion Reactions occur when a hydrocarbon reacts with oxygen gas. This is also called burning!!! In order to burn something you need the 3 things in the “fire triangle”:1) A Fuel (hydrocarbon)2) Oxygen to burn it with3) Something to ignite the reaction (spark)


. Hydrocarbon Combustion Reactions :. Hydrocarbon Combustion Reactions In general: CxHy + O2 ? CO2 + H2O Products in combustion are ALWAYS carbon dioxide and water. (although incomplete burning does cause some by-products like carbon monoxide) Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18)


. Hydrocarbon Combustion Reactions :. Hydrocarbon Combustion Reactions Edgar Allen Poe’s drooping eyes and mouth are potential signs of CO poisoning.


. Hydrocarbon Combustion Reactions :. Hydrocarbon Combustion Reactions Example C5H12 + O2 ? CO2 + H2O Write the products and balance the following combustion reaction: C10H22 + O2 ? CO2 + H2O 5 6 8


. Hydrocarbon Combustion Reactions :. Hydrocarbon Combustion Reactions Example C5H12 + O2 ? CO2 + H2O Write the products and balance the following combustion reaction: 2 C10H22 + 31 O2 ? 20 CO2 + 22 H2O 5 6 8


Mixed Practice :Mixed Practice State the type, predict the products, and balance the following reactions: BaCl2 + H2SO4 ? C6H12 + O2 ? Zn + CuSO4 ? Cs + Br2 ? FeCO3 ?