Unit 7 Chemical Reactions Types of Reactions

Type of Reactions Chemical reactions are classified into five general types

Synthesis (Combination) Two or more elements or simple compounds combine to form (synthesize) one product A + B AB 2Mg + O 2 2MgO 2Na + Cl 2 2NaCl When two elements combine in synthesis, the product is a compound made of their respective ions.

Synthesis YouTube - Reaction of aluminium with bromine

Synthesis (practice) Predict the products. Write and balance the following synthesis reaction equations. Sodium metal reacts with chlorine gas Na (s) + Cl 2(g)  Solid Magnesium reacts with fluorine gas Mg (s) + F 2(g)  Aluminum metal reacts with fluorine gas Al (s) + F 2(g) 

Decomposition One substance is broken down (split) into two or more simpler substances. ABA + B 2HgO2Hg + O 2 2KClO 3 2KCl + 3 O 2 a compound made of two elements, decomposes into those elements.

Decomposition

Decomposition Practice Predict the products. Then, write and balance the following decomposition reaction equations: Solid Lead (IV) oxide decomposes PbO 2(s)  Aluminum nitride decomposes AlN (s) 

Learning Check 1 Classify the following reactions as 1) synthesis or 2) decomposition: ___A. H 2 + Br 2 2HBr ___B. Al 2 (CO 3 ) 3 Al 2 O 3 + 3CO 2 ___C. 4 Al + 3C Al 4 C 3

Combustion A reaction in which a hydrocarbon (compound made up of H and C) reacts with oxygen and the products are carbon dioxide and water CH 4 + 2O 2 CO 2 + 2H 2 O C 3 H 8 + 5O 2 3CO 2 + 4H 2 O

Combustion Practice Complete and Balance the combustion equation ___C 5 H 12 + ___O 2

Single Replacement (Displacement) One element takes the place of an element in a reacting compound. A + BC AC + B Zn + 2HCl ZnCl 2 + H 2 Fe + CuSO 4 FeSO 4 +Cu  A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-).  Depends on the relative reactivity's of the two metals.

Single Replacement (Displacement) Practice YouTube - Thermite reaction

Single Replacement Displacement) The activity series of metals lists metals in order of decreasing reactivity. A metal will replace any metal listed below. Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Iron Lead Hydrogen Copper Mercury silver

Single Replacement (Displacement) Practice Sodium chloride solid reacts with fluorine gas NaCl (s) + F 2(g)  Aluminum metal reacts with aqueous copper (II) nitrate Al (s) + Cu(NO 3 ) 2(aq) 

Double Replacement (Displacement) Two elements in reactants take the place of each other AB + CD AD + CB AgNO 3 + NaClAgCl + NaNO 3 ZnS + 2HCl ZnCl 2 +H 2 S

Double Replacement (Displacement) YouTube - Double Replacement Reactions

Think about it like “foil”ing in algebra, first and last ions go together ; inside ions go together Example: AgNO 3(aq) + NaCl (s)  AgCl (s) + NaNO 3(aq) Another example: K 2 SO 4(aq) + Ba(NO 3 ) 2(aq)  KNO 3(aq) + BaSO 4(s)

Classify the following reactions as 1) single replacement 2) double replacement __A. 2Al + 3H 2 SO 4 Al 2 (SO 4 ) 3 + 3H 2 __B. Na 2 SO 4 + 2AgNO 3 Ag 2 SO 4 + 2NaNO 3 __C. 3C + Fe 2 O 3 2Fe + 3CO

Double Replacement Practice Predict the products. Balance the equation 1. HCl (aq) + AgNO 3(aq)  2. CaCl 2(aq) + Na 3 PO 4(aq) 

Unit 8 Chemical Reactions Types of Reactions