Solutions_1Explain_24.pptx

Unit 5: Potions (Solutions, Acids & Bases) House Challenge #2 Review 1) Write the complete, balanced reaction – including states – for the following reactions (5 points each) Nitric acid & calcium hydroxide Silver acetate & copper (II) sulfate 2) What (chemically)makes a substance acidic? Wh...

Unit 5: Potions (Solutions, Acids & Bases) House Challenge #2 Review 1) Write the complete, balanced reaction – including states – for the following reactions (5 points each) Nitric acid & calcium hydroxide Silver acetate & copper (II) sulfate 2) What (chemically)makes a substance acidic? What makes a substance basic? (5 points) 3) How would you test the pH of a substance? What results would you expect? (5 points) 4) What are 2 methods you could use to increase the solubility of a substance? Solutions & Reactions House Challenge #3  10 points for thoughtful, detailed answers for: C) E) F) G) *Group work & collaboration matter!  Solution Homogeneous mixture of 2+ substances Different substances cannot be mechanically separated or seen.  2 parts: −Solute −What is dissolved −Solvent −What solute is dissolved into Empirical Properties of Aqueous Solutions 1) Solubility −Does it dissolve? -Ionic -Solubility table A) Soluble (aq) B) Slightly soluble (s)-Molecular -Like dissolves like -Polar or non- polar molecule?  2) Conductivity A) Electrolyte −Conductive when dissolved in water −Ionic compounds (aq) −Acids/bases B) Non-electrolyte −Not conductive when dissolved in water −Molecular compounds −Ionic compounds (s)  3) pH A) Acid −Turns litmus red −pH 7 −OH- in solution C) Neutral −No change in litmus −pH =7 Explaining Solutions Why do some compounds create electrolytes while other compounds do not? −Arrhenius −When a substance dissolves, particles of the substance separate from each other −What separates?  I) Very Soluble Ionic Compounds (aq) −Ions separate from the crystal lattice −Dissociation  -Dissociation equations: NaCl (s)Na →+ (aq) + Cl - (aq) b e u st d ! M nce al a b 2 NH4+ (aq) + SO42- (NH4)2SO4 (s) →(aq) -Water is NOT part of the dissociation −Practice −Write the dissociation equation for the following: −Ammonium carbonate −Copper (II) chloride −Iron (III) nitrate −Calcium hydroxide −Practice −Write the dissociation equation for the following: −Ammonium carbonate −(NH4)2CO3 (s) → 2NH4+ (aq) + CO3 2- (aq) −Copper (II) chloride −CuCl2 (s) → Cu2+ (aq) + 2Cl- (aq) −Iron (III) nitrate −Fe(NO3)3 (s) → Fe3+ (aq) + 3NO3- (aq) −Calcium hydroxide −Ca(OH)2 (s) → Ca2+ (aq) + 2OH- (aq)  II) Slightly Soluble Ionic Compounds (s) −Remains as a solid ionic compound −Do NOT dissociate AgBr(s)AgBr (s) −No ions −No conductivity −Neutral pH  III) Soluble Molecular Compounds −Polar molecules with HB −Remain as compound particles C12H22O11 (s) C12H22O11 (aq) −No ions −No conductivity −Neutral pH  IV) Insoluble Molecular Compounds −Non-polar molecules −Remain as compound particles CH4 (g) CH4 (g) −No ions −No conductivity −Neutral pH  V) Bases −Bases are ionic compounds −Very soluble (aq) = dissociate −Slightly soluble (s) = do not dissociate Ba2+ (aq) + 2 OH- Ba(OH)2 (s) → (aq) Responsible for properties of base  VI) Acids −Molecular compounds −Empirical evidence shows they dissolve & form electrolytes −Must contain ions −Ionization −Process that converts neutral atoms into ions  Not sure if it is a strong acid? Check your data −Strong acids sheet! HCl (g) HCl (aq) H+(aq) + Cl-(aq) Responsible for properties of acid −Weak acids −Dissolve, but do not completely ionize HF(aq) HF(g)  Workbook – Part A  It is necessary to know the major entities (things) present in a solution −Properties of solution −Reactions Major entities −(s) or (aq)? −Ions? −Neutral molecules? p. 201  Workbook Practice – Part #3 KCl(s) Ba(OH)2(s) Zn(s) C6H5COO(s) Ca3(PO4)2(s) C25H52(s) C12H22O11(s) Workbook Practice – Part A #4 Lab Assign 1: Qualitative Analysis Energy Changes in Solutions  Endothermic −Energy is absorbed from environment −Reactant −Used to break bonds Exothermic −Energy is released into environment −Product −New bonds are formed  NET energy change is determined by which process occurs more NaCl(s) → Na+ + Cl- → Na+(aq) + Cl-(aq) Need to break ionic bondsNew bonds form between Energy is required water molecules & ions (endo) Energy is released (exo) −Dissolving CaCl2… −Exothermic −More bonds are created than are broken −Dissolving NaNO3… −Endothermic −More bonds are broken than are created