Ch. 8.2 Types of Reactions Chemical Reactions

POINT > Describe synthesis reactions POINT > Describe decomposition reactions POINT > Describe single replacement reactions POINT > Describe double replacement reactions POINT > Describe combustion reactions

POINT > Define and describe synthesis reactions In a synthesis reaction, two or more substances react to form a single compound Ex. 4 Fe + 3 O2 2 Fe2O3 Ex. 2 Na + I2 2 NaI Ex. 2 K + Cl2 2 KCl These are also called composition or combination reactions

POINT > Define and describe decomposition reactions In a decomposition reaction a single compound breaks down into two or more products Ex. 2 H2O2 2 H2O + O2 Ex. Mg3N2 3 Mg + N2

POINT > Describe single replacement reactions In a single replacement reaction one element replaces a second element in a compound Ex. K + NaOH KOH + Na Ex. 2 Al + 3 ZnSO4 Al2(SO4)3 + 3 Zn

POINT > Describe single replacement reactions Note: An element will only replace another element if the first element is more reactive than the second element The Activity Series (p. 272) is your guide to this (and your cheat sheet) Na + LiOH NaOH + Li

POINT > Describe single replacement reactions An element higher on the list can replace an element lower on the list, but not the other way around

POINT > Describe single replacement reactions Note: A metal will only replace another metal if the first metal is more reactive than the second metal. Na + LiOH NaOH + Li X X X X X No Reaction

WB CHECK: Identify the type of reaction: 2 KClO3 2 KCl + 3 O2 U + 3F2 UF6 Will the following reactions occur? 2KCl + Ca CaCl2 + 2K 3 ZnCl2 + 2 Al 2 AlCl3 + 3 Zn Fe2(SO4)3 + 3Mg 3 MgSO4 + 2 Fe

POINT > Describe double replacement reactions In a double replacement reaction, positive ions (cations) are exchanged between two compounds Ex. Pb(NO3)2 + 2 NaI PbI2 + 2 NaNO3 Ex. Mg(OH)2 + 2 HCl MgCl2 + 2 H2O One of the products is often a precipitate (insoluble in water)

POINT > Describe combustion reactions In combustion reactions an element or compound reacts with oxygen producing heat and/or light Ex. 2 C4H10 + 13 O2 10 H2O + 8 CO2 Ex. CH4 + 2 O2 2 H2O + CO2 Ex. C6H12O6 + 6 O2 6 H2O + 6 CO2 * H2O and CO2 are the products of hydrocarbon or carbohydrate combustion

Homework: Read pages 262-273 F.A. #1-4 page 270 F.A. #1-4 page 273 Composition Reaction WS