150 likes | 292 Views
Topic: Reactions in Aqueous Solution Do Now: Pick up 2 tests. Add correct answers to your test. Formation of a precipitate. 2 aqueous solutions mixing to produce a solid. Reactions in aqueous solution. Many reactions, esp. many double replacement reactions, occur in water.
E N D
Topic: Reactions in Aqueous SolutionDo Now: Pick up 2 tests. Add correct answers to your test
Formation of a precipitate 2 aqueous solutions mixing to produce a solid
Reactions in aqueous solution • Many reactions, esp. many double replacement reactions, occur in water. • What happens when substances dissolve in water? • Depends on if they are ionic or covalent.
Dissolving an Ionic Substance in a WaterIonc Dissolution (IONS) • Example: • NaCl(s) Na+(aq) + Cl-(aq) • CaCl2(s) Ca2+(aq) + 2Cl-(aq) • AlCl3(s) Al3+(aq) + 3Cl-(aq) • The ions are spread out among the water molecules.
Dissolving a Covalent Substance in waterMolecular Dissolution (molecules) • Ex: glucose • C6H12O6(s) C6H12O6(aq) • The sugar molecules are spread out among the water molecules.
Not everything dissolves in water • Soluble = dissolves in water • Insoluble = doesn’t dissolve in water • Miscible = 2 liquids that dissolve • Immiscible = 2 liquids that don’t dissolve
How can you tell….?!!!?? • Like Dissolve Like • Water is polar, so most polar compounds will dissolve in water • All ionic compounds are polar • Use table F to see if it will dissolve in water • Covalent compound • Polar will dissolve in water • Nonpolar will not dissolve in water • NP (LOOK AT MOLECULAR SHAPE!) • Diatomic • Nobel gas • Pure hydrocarbon • Small symmetrical
Double Replacement Reactions • Often occur when you mix 2 solutions of ionic compounds. • 1 product may be water or • 1 product may be a gas or • 1 product may be a solid • We say these reactions “go to completion.”
Reactions producing Solids • Precipitation: the opposite of dissolving! • What do you see in the following clips: -TIGER VIDEOS
Reactions producing Solids p. 1 in your packet
Complete Ionic Equations 2K+1(aq) + CrO4-2(aq) + Ba2+(aq) + 2NO3-1(aq)2K+(aq)+ 2NO3-1(aq)+ BaCrO4(s) Ionic substances that dissolve are written as ions in solution!
Net Ionic Equations 2K+1(aq) + CrO4-2(aq) + Ba2+(aq) + 2NO3-1(aq)2K+(aq)+ 2NO3-1(aq)+ BaCrO4(s) Notice that some ions do not participate in the reaction. They are spectator ions. Cross out all the spectator ions & you get the net ionic equation. CrO4+2(aq)+ Ba2+(aq) BaCrO4(s)
Reactions that form Water HBr(aq) + NaOH(aq) H2O(l) + NaBr(aq) H+(aq) + Br-(aq) + Na+(aq) + OH-(aq) H2O(l) + Na+(aq) + Br-(aq) H+(aq) + OH-(aq) H2O(l)
Reactions that form Gases HCl(aq) + NaHCO3(aq) H2O(l) + CO2(g) + NaCl(aq) H+(aq) + Cl-(aq) + Na+(aq) + HCO3-(aq) H2O(l) + CO2(g) + Na+(aq) + Cl-(aq) H+(aq) + HCO3-(aq) H2O(l) + CO2(g)
Conservation of Charge • Total charge on reactant side must equal total charge on product side. • Mass of reactants = mass of products • Total # Atoms of reactants = Total # Atoms of products Conservation of Mass