Chemical Reactions Chapter 11

Describing chemical change word equations reactants  products law of conservation of mass EX: iron + oxygen  iron (III) oxide EX: hydrogen peroxide  water + oxygen EX: methane + oxygen  carbon dioxide + water

Describing chemical change Chemical equations Fe(s) + O2(g)  Fe2O3 (s) s – solid; l – liquid; g – gas; aq – aqueous solution catalysts listed above arrow

Describing chemical change balancing equations - advice numbers in front = coefficients CAN’T change subscripts number of element on one side = other side if polyatomic is unchanged, count it as a whole try to balance everything BUT hydrogens, oxygens 1st double check when completed make sure it’s reduced combustion reactions are harder

Practice writing and balancing EX: silver nitrate + hydrosulfuric acid yields silver sulfide + nitric acid EX: manganese (IV) oxide + hydrochloric acid yields manganese (II) chloride + water + chlorine gas EX: zinc hydroxide + phosphoric acid yields zinc phosphate + water

Practice writing and balancing EX: hydrogen gas + sulfur yields hydrogen sulfide EX: iron (III) chloride + calcium hydroxide yields iron (III) hydroxide + calcium chloride Do problems 1 – 6, 9 – 11; pp. 349-354

Types of chemical reactions Single replacement EX: Mg + ZnCl2  Zn + MgCl2 EX: Br2 + 2AgI  I2 + 2AgBr

Types of chemical reactions Double replacement EX: AgNO3 + H2SO4  HNO3 + Ag2SO4 EX: NaOH + HCl  H2O + NaCl

Types of chemical reactions Synthesis/Combination 2K + Cl2  2KCl 2S + 3O2  2SO3 N2 + 3H2  2NH3

Types of chemical reactions Decomposition 2NaHCO3  CO2 + H2O + Na2CO3 2NaBr  2Na + Br2

Types of chemical reactions Combustion – incomplete (CO) or complete (CO2) C6H12O6 completely combusts. C6H12O6 + 6O2  6H2O + 6CO2 Ethane (C2H6) incompletely combusts. 2C2H6 + 5O2  4CO + 6H2O

Predicting Solubility A) All common salts of the Group 1 elements and ammonium ion are soluble. (column 1 w/ 17) B) All common acetates and nitrates are soluble. C) All binary compounds of Group 17 elements (other than F) with metals are soluble except those of silver, mercury (I), and lead. D) All sulfates are soluble except those of barium, strontium, lead, calcium, silver, and mercury. E) Except for those in Rule A, carbonates, hydroxides, oxides, sulfides, and phosphates are insoluble.

Predicting Solubility EX: BaSO4 EX: Pb(NO3)2 EX: (NH4)2S EX: CaS EX: AgF EX: Ca(C2H3O2)2 EX: NaCl EX: MgO

Net Ionic Equations AgNO3(aq) + NaCl (aq)  AgCl (s) + NaNO3(aq) what are the ions in the aqueous state? Ag+1 (aq) + NO3 -1(aq) + Na+1 (aq) + Cl-1 (aq)  AgCl(s) + Na+1 (aq) + NO3 -1(aq) Eliminate the aqueous redundancy on both sides; spectator ions – ions not directly involved in the reaction (cancelled out) Ag+1 (aq) + Cl-1 (aq)  AgCl(s) Balance charge, then elements

Net Ionic Equations Pb (s) + AgNO3 (aq)  Ag (s) + Pb(NO3)2 (aq) ANS: Pb(s) + 2Ag+1(aq)  2Ag(s) + Pb+2(aq)