Honors Chemistry Chapter 11 Note Packet (student’s edition) Chapter 11 problems: Chapter 11 figures: 11.1 36, 40, 52, 54, 57, 67, 71, 72 All of the figures are important and Table 1 Describing Chemical Reactions reactants chemical equations describe example – creation of hydrogen chloride: H2 + Cl2 Say: other example - creation of sodium chloride: Na + Cl2 Say: Showing Phases in Chemical Reactions: gas = liquid = solid = aqueous Ex1: NaCl(s) = Ex2: NaCl(aq) = Ex3: H2O(l) = other symbols: (not aqueous - redundant) (one arrow) = reactions (2 arrows) = reaction H = Change in cat = (a substance that speeds up a reaction without being in the reaction) ppt = (solid - only found on side) Balancing Chemical Equations: truly a trial and error process if there ever was one Helpful hints: 1. 1 atom at a time 2. Balance atoms that appear only 1X per side first 3. Balance as whole units 4. Balance diatomic elements last 5. Save H + O for last if this doesn’t succeed, try everything (particularly with combustion) Showing Energy Changes in Equations: endothermic C H is C + heat H is A + B + heat exothermic A + B Interpreting Chemical Equation - what do chemical equations really mean anyway? H2O 11.2 H2 + O2 (not balanced) H2O H2 + atoms atoms + atoms (equal) g g + g (equal) moles + mole moles O2 (equal) (not equal - doesn’t have to) Types of Chemical Reactions 5 types - synthesis, decomposition, combustion, single replacement, double replacement remember - first you’ve got to find the right products, then you gotta balance 1. Synthesis ( direct combination ) - needs to happen general formula (element + element): Ba + S Ex2 Mg + Cl2 Ex3: Ex4: Al + 3Cl2 Na + O2 Ex1: 2. Decomposition (analysis) - needs Ex7: + B AB to happen (usually general formula (molecule + element): Ex5: Ex6: A AB FeCl3 + HgO + MgSO4. 7 H2O ) A + B + (hydrate) 3. Combustion - the reaction of hydrocarbons and oxygen to yield . general formula (“CHO”): Ex8: combustion of CH4 Ex9: combustion of C3H8 CxHy + Ex10: combustion of C4H10 Ex11: combustion of C2H5OH O2 and CO2 + H2O 4. Single Replacement - take place in a) Type 1: solutions and need energy ions switch general formula (molecule + element): AB + M Ex12: HI Ex13: AlCl3 Ex14: Ca b) Type 2: + Mg MB + A + Ca + + HOH + + ions switch general formula (molecule + element): AB + X AX + F2 Ex15: NaCl + Ex16: BaS + O2 B + + 5. Double Replacement - again - aqueous solution - little energy - usually forms one soluble ionic product (aka - aqueous) and either a ppt, water, or a gas that bubbles out of water general formula (molecule + molecule): AB + CD CB + AD Ex17: FeCl3 + NaOH NaOH + Ex18: H2SO4 + NH4Cl + + Ex19: NaOH NH3(g) + H2O(l) + NaCl(aq) Hey, some reactions happen and some don’t. For synthesis, combustion, and decomposition, we will assume they all sufficient activation energy (Ea). For single replacement, use the Ex20: Ex21: Ex23: ! Ca + Ca + Al + H2O Al + H(OH) + HI Ex22: Al Cu + given H2O H(OH) + + HI Rules for the single replacement activity series: 1. 2. 3. 4. Any single element above an element in a compound will it. The top 5 elements react with . Metals above H react with (molecules that start with H – not water). The nonmetal reactivity series is ... For double replacement reactions, use a solubility table and the following rules: 1. If one of the products formed is water, the reaction . 2. If a gas is formed, the reaction . 3. If an insoluble product forms ( ), the reaction (actually a reaction may happen when two soluble products form, but it doesn’t go to completion and is not directly observable). Ex24: Na2CrO4 + Ex25: FeCl3 + KCl KOH Note: precipitate symbols include + 11.3 Reactions in Aqueous Solution Ions in solutions for aqueous solutions. Ionic compounds are . When you put them in water, they Ex1: NaBr(s) + Ex2: MgCl2(s) H2O(l) + H2O(l) : Also happens with some molecular substances - particularly Ex3: HCl(g) + Ex4: H2CrO4(s) H2O(l) : H2O(l) + Writing Ionic Equations so far we’ve looked at molecular equations now it’s time for ionic equations - show what happens to the ions in a reaction Ex1: (“molecular” equation) Fe(s) + HF(aq) (total ionic) (net ionic) spectator ion = Spectator ions are ions that undergo in a chemical reaction. Ex2: (“molecular” equation) H2SO4(aq) + NaOH(aq) (total ionic) (net ionic) spectator ions = Conservation of Charge - charges must NIB in a chemical reaction. Solubility Trends Cations - very soluble very insoluble- Anions - very soluble for monotomics very insoluble sulfides general trend: As size decreases, solubility .