Chapter 8 test

Terms you must know Decomposition reaction Activity series Spectator ions Balanced equation Double-replacement Catalyst Combustion reaction Net ionic reaction Single replacement Combination reaction

Be familiar with the parts of a chemical equation Reactants Products Yield symbol Catalyst Heat (energy)

Know the rules for balancing equations Determine the correct formulas for all reactants and products Write the reactants on the left side of the yield sign and the products on the right Count the number of atoms of each element on each side of the yield sign Balance the elements (or polyatomic ions) one at a time using coefficients (never change formulas) Make sure coefficients are in lowest ratios

Balancing strategy CaCl2(aq) + H3PO4(aq) Ca3(PO4)2(s) + HCl(aq) Here’s an unbalanced equation Let’s start by listing all the atoms and polyatomic ions in a center column

Balancing strategy CaCl2(aq) + H3PO4(aq) Ca3(PO4)2(s) + HCl(aq) PO4 Ca Now, let’s count up all the atoms of each element on each side of the yield sign

Balancing strategy CaCl2(aq) + H3PO4(aq) Ca3(PO4)2(s) + HCl(aq) Now, let’s start changing the amounts of each element by changing the coefficients

Balancing strategy 3CaCl2(aq) + 2H3PO4(aq) Ca3(PO4)2(s) + 6HCl(aq) red, blue, green … in that order!

Let’s try these… ___ V2O5 + ___ CaS  ___ CaO + ___ V2S5 ___ Mn(NO2)2 + ___ BeCl2  ___ Be(NO2)2 + ___ MnCl2 ___ AgBr + ___ GaPO4  ___ Ag3PO4 + ___ GaBr3 ___ H2SO4 + ___ B(OH)3  __ B2(SO4)3 + ___ H2O ___ S8 + ___ O2  ___ SO2 10) ___ Fe + ___ AgNO3  ___ Fe(NO3)2 + ___ Ag

___ AgBr + ___ GaPO4  ___ Ag3PO4 + ___ GaBr3

___ H2SO4 + ___ B(OH)3  __ B2(SO4)3 + ___ H2O

___ Fe + ___ AgNO3  ___ Fe(NO3)2 + ___ Ag

Balancing equations We do it because of the law of conservation of mass Atoms are not created in chemical reactions but new compounds are

Be familiar with the reactivity series of metals – will some single replacement reactions proceed?

Will these reactions proceed? ____ Ca + ____ Na2SO4  ____ Pb + ____ Fe(NO3)3 

Will these reactions proceed? ____ Ca + ____ Na2SO4  ____ Pb + ____ Fe(NO3)3  These reactions will only occur if the pure element on the reactant side of the equation is higher on the activity series than the element it replaces. These reactions will not proceed!

Be familiar with the characteristics of all types of reactions: Combination Decomposition Single replacement may or may not proceed Double replacement Either an aqueous solution OR a chemical reaction will occur Combustion Hydrocarbons + O2 yields CO2 + H2O

____ NaBr + ____ H3PO4  ____ Na3PO4 + ____ HBr Type of reaction: ____________________ ____ Ca(OH)2 + ____ Al2(SO4)3  ____ CaSO4 + ____ Al(OH)3 ____ Mg + ____ Fe2O3  ____ Fe + ____ MgO ____ C2H4 + ____ O2  ____ CO2 + ____ H2O ____ PbSO4  ____ PbSO3 + ____ O2

____ NaBr + ____ H3PO4  ____ Na3PO4 + ____ HBr Type of reaction: ____________________ ____ Ca(OH)2 + ____ Al2(SO4)3  ____ CaSO4 + ____ Al(OH)3 ____ Mg + ____ Fe2O3  ____ Fe + ____ MgO

____ Ca(OH)2 + ____ Al2(SO4)3  ____ CaSO4 + ____ Al(OH)3

Be familiar with diatomic atoms H2, O2, Cl2, N2, etc. These are not ionic; they are molecular There is no charge They can be reactants or products They can be the products in net ionic reactions

Understand the solubility rules These will tell you whether you have a precipitate or not This is essential in writing net ionic reactions

Understand net ionic equations There is no net ionic reaction unless you have a solid, liquid or gas formed Otherwise, all you have is a bunch of ions in an aqueous solution These are characteristic of single and double replacement reactions

Understand combustion reactions O2 is a reactant CO2 and H2O are products Know how to balance these…sometimes the coefficients are quite large