CHE 101 Lecture Outline Chapter 4Chapter 4:Aqueous Reactions & MolarityWhat Happens to Solid Chemicals when they Dissolve? Solids exist in a crystal lattice  repeating pattern of ________ions or molecules________ Salt (NaCl) = Sugar (C12H22O11): Sucrose=_____Ions_____________ _____Molecules________ Hydration – water molecules ____ break apart______the crystal lattice of solids 2 Types of break ups:1. Break apart into individual _____molecules______________________  Occurs when the chemical is _____molecular______________2. Break apart into _____ions_______, a process called Dissociation Occurs when the chemical is __________ionic,acidic, or basic____________ Resulting in an _______electrolyte____________ solutionDissolved ___molecules__________(Ex: sucrose)Dissolved ____ions______(Ex: Na+ & Cl)1CHE 101 Lecture Outline Chapter 4Electrolytes Electrolytes – a chemical dissolved in water that conducts ______electricity__________dueto the presence of ___IONS______________ High conductance values means _____more ions_______ - Which substance will conduct more? __The one with more ions__________ Dissociation equations- determines ________which ions__________ are present- How to write: separate into ions, place charges above symbols, then balanceNaCl(aq)  Na+(aq) + Cl(aq) _2__ Total ionsCa3(PO4)2(aq)  __5_ Total ionsTypes of Electrolytes1. Strong Electrolytes – ____high________ conductance  ____Many________ ions (_____100%________ dissociation) Made up of: ___Ionic___________ compounds, _____Strong________ acids & _____Strong____________ bases2. Weak Electrolytes – ___low________ conductance  _____Few_______ ions (_______Partial___________ dissociation) • More _______molecules________ than ____ions_____ present Made up of: ____Weak________ acids & ______Weak________ bases3. Non-electrolytes – ___No_____ conductance  ___No_____ ions (_____No______ dissociation)  Made up of: ______Molecular_________ compounds2CHE 101 Lecture Outline Chapter 4Acid/Base Definitions Acids – Always produce a proton ___(H+)______ ion Usually either start w/____H+______ or end w/__COOH___________ Protons available (____active____) in an acid = # of ___FRONT____ H’s- HCl = __1___ H+- H3PO4 = __3___ H+- HC2H3O2 = __1___ H+ Bases – Always produce a hydroxide __(OH-)____ ion3CHE 101 Lecture Outline Chapter 4STRONG Acid/Bases They dissociate ____100%_______, thus _____strong_________electrolytes Use ______1 way____________ arrow (___>______) in dissociation eq. Strong acids: MEMORIZE LIST!  Strong bases: MEMORIZE LISTWEAK Acids/Bases Dissociate ______partially____________ (___<100%______), thus __weak______ electrolytes Breaks into ions, but also ___reforms__________original molecule• More _______original molecules__________present Use ________2 way___________________ arrow ( .. ) in dissociation eq. Weak acids: NOT on strong list Weak bases: many exist, but memorize:___NH3________!  Caution: _____NH4+______ is not a base!4CHE 101 Lecture Outline Chapter 4Questions:4.2: Indicate the type of Electrolyte for SrF2.A. StrongB. WeakC. Non4.3: Indicate the type of Electrolyte for NH4Br.A. StrongB. WeakC. Non4.4: Which chemical will conduct more?A. SrF2B. NH4BrC. The conduct the sameTypes of Reactions Many reactions have characteristics in common 5 Basic types:1. Combination2. Decomposition3. Combustion4. Single Replacement5. Double ReplacementHow to Write a Balanced Equation (Extended) 1. Write correct chemical formulas  If an _______________ compound or an ___________________, use IONS • Positive ion written first2. Add _____________ to all chemicals See next 3. Balance each element by adjusting coefficients  Smallest whole-numbers are preferred  NOTE: When forming products: _______________ move subscripts unless a _______________________ ion!!5CHE 101 Lecture Outline Chapter 4How to Predict Phases1. Metals = solids2. Diatomics = gases3. Acids = _________________4. Solutions = __________________5. Water = ____________________ Unless specified6. Solubility Rules: Soluble: will _______dissolve (aq)____________________________ What is the phase of:- CaBr2 = ____aq________- Al2S3 = ____s_________- PbI2 = ______s_______ MUST know ions that are ______________________ soluble6CHE 101 Lecture Outline Chapter 4SINGLE Replacement Rxns  Single Replacement – a ___free_________ element (in _____natural__________ state) substitutes for the _____cation_________ in a different compoundSample Problems Write a balanced eq:A. 2Al(s) + 6HC2H3O2(aq)  2Al(C2H3O2)3 (aq) +3H2(g)B. Ca(s) + Na3PO4(aq) Ca2+PO43- +Na3Ca(s) + 2Na3PO4(aq)  Ca3(PO4)2 (s)+6Na(s)DOUBLE Replacement Rxns (LAB 3) Double Replacement – _____cation__________ from one compound interacts with the _____anion__________ from the other compound Aka: _________Metathesis___________ rxn  There are many types of double replacement rxns1. Precipitation Rxn (double replacement) 72 Fe (s )+3 CdCl2(aq )→2 FeCl3(aq )+3 Cd( s)3MgCl2(aq )+2 K3PO4(aq )→Mg3(PO4)2(s )+6KCl( aq )CHE 101 Lecture Outline Chapter 4 Precipitation Rxn – 2 compounds react to form an insoluble ____solid______ compound (aka. _____precipitate____________________)  Looks _____cloudy___________ Cu(NO3)3(aq) +(NH4)2CO3(aq) Cu3+CO32- + NH4+NO3-2Cu(NO3)3(aq) + 3(NH4)2CO3(aq) Cu2 (CO3)3 (s) + 6NH4NO3- (aq)2. Neutralization Rxn (double replacement) Neutralization rxn: Salt – any _______ionic___________ compoundHI(aq) + Ca(OH)2(aq)  Ca2+I- + H+OH-2HI(aq) + Ca(OH)2(aq)  CaI2 (aq) +2H2O(l)3. Unstable product (double replacement) Sometimes an _______unstable_________________ compound is produced This compound immediately ______decomposes__________ into new chemicalsa) H2CO3  _____CO2 (g) +H2O(l)________________________b) H2SO3  _____SO2 (g) + H2O (l)_________________________K2CO3(aq) + HCl(aq)  K+ Cl- +H+ CO32-K2CO3(aq) + HCl(aq)  KCl(aq) + H2CO3 (aq) UNSTABLEK2CO3 (aq) + 2HCl (aq) >>>>>> 2KCl (aq) +CO2 (g) + H2O (l)8Acid (aq )+Base (aq )→H2O(l )+saltCHE 101 Lecture Outline Chapter 4Descriptive Equations (Lab 3) You’ve just learned to write & balance ______Molecular______chemical equations Ex: Since chemicals are dissolved in water, many will ________dissociate____________ Can _______re-write___________ equations to indicate what’s actually in the