Solutions Ch.12 & 13

Liquids

Condensed States Liquids and Solids Liquids and Solids Higher densities Higher densities Slightly compressible Slightly compressible Slow diffusion(mixing) Slow diffusion(mixing) Physical state depends on strength of attraction between particles Physical state depends on strength of attraction between particles

Gases: weak forces of attraction Gases: weak forces of attraction Liquids: stronger forces Liquids: stronger forces Solids: really strong forces Solids: really strong forces Forces of attraction  intermolecular forces Forces of attraction  intermolecular forces

Properties of Liquids Viscosity Viscosity Friction, resistance to motion Friction, resistance to motion syrup vs. water syrup vs. water Stronger intermolecular forces = Stronger intermolecular forces = greater viscosity greater viscosity Low temperatures Low temperatures greater viscosity greater viscosity

Properties of Liquids Surface Tension Surface Tension Tight film on surface of water Tight film on surface of water Uneven forces at surface Uneven forces at surface Causes rain to fall in drops! Causes rain to fall in drops! Video - 30 Video - 30

Solutions

Properties of Solutions Homogenous mixtures Homogenous mixtures 1. Particles are very small 2. Particles mixed evenly 3. Particles will not separate Made of solute (gets dissolved) and solvent (does the dissolving) Made of solute (gets dissolved) and solvent (does the dissolving)

Properties of Solutions Soluble - substance dissolves in another substance Soluble - substance dissolves in another substance Insoluble – substance does NOT dissolve Insoluble – substance does NOT dissolve

Types of Solutions Solid Solutions Solid Solutions Alloys: mixture of 2 or more metals Alloys: mixture of 2 or more metals Melting the metals, mixing and cooling Melting the metals, mixing and cooling Sterling silver: silver and copper Sterling silver: silver and copper Gaseous Solutions: Gaseous Solutions: Mixture of gases (air) Mixture of gases (air)

Types of Solutions Liquid Solutions: Liquid Solutions: Solvent and Solution are liquids Solvent and Solution are liquids Solute: solid, liq. or gas Solute: solid, liq. or gas Mixing liquids: Mixing liquids: Miscible: liquids that mix thoroughly Miscible: liquids that mix thoroughly Immiscible: liquids that cannot mix Immiscible: liquids that cannot mix

Types of Solutions Aqueous Solutions: Aqueous Solutions: Water is “universal solvent” Water is “universal solvent” Ionic compounds dissolve to give ions Ionic compounds dissolve to give ions Solution conducts electricity - electrolyte Solution conducts electricity - electrolyte Solutions that do not - nonelectrolyte Solutions that do not - nonelectrolyte

Solubility Ch.12 Section 2

Solubility Def: amount of solute that will dissolve in a specific solvent Def: amount of solute that will dissolve in a specific solvent Temp. and Pressure(gas) given with solubility Temp. and Pressure(gas) given with solubility Solubility can be altered by: Solubility can be altered by: Type of Solvent (Polar/Nonpolar) Type of Solvent (Polar/Nonpolar) Surface area of solute particles Surface area of solute particles Molar Mass of solute or solvent Molar Mass of solute or solvent Pressure Pressure Temperature of solvent Temperature of solvent

Type of Solvent “Like dissolves like” “Like dissolves like” Water is polar  will only dissolve polar solutes Water is polar  will only dissolve polar solutes Paint thinner and gasoline are nonpolar Paint thinner and gasoline are nonpolar SOAP – universal polar and nonpolar ends SOAP – universal polar and nonpolar ends

Surface Area Solvents can only dissolve the surface of the solute particles Solvents can only dissolve the surface of the solute particles Smaller particles dissolve faster Smaller particles dissolve faster Stirring also increases # of collisions Stirring also increases # of collisions

Mass of Solute or Solvent A large molar mass SOLUTE will need more energy to break up particles A large molar mass SOLUTE will need more energy to break up particles A large molar mass SOLVENT has more energy to break up solute A large molar mass SOLVENT has more energy to break up solute

Pressure Mainly affects solubility of gas solutes Mainly affects solubility of gas solutes Henry’s Law: solubility of gas is directly proportional to partial pressure of the gas on the liquid. Henry’s Law: solubility of gas is directly proportional to partial pressure of the gas on the liquid. Video - 48 Video - 48

Temperature Higher temp. = faster particles = harder collisions = smaller particles Higher temp. = faster particles = harder collisions = smaller particles Allows solute to mix in with solvent faster Allows solute to mix in with solvent faster

Heats of Solution Energy is involved in forming solutions Energy is involved in forming solutions Endothermic rxn: a rxn that absorbs heat (feels cold) Endothermic rxn: a rxn that absorbs heat (feels cold) Exothermic rxn: a rxn that gives off heat (feels warm) Exothermic rxn: a rxn that gives off heat (feels warm)

Saturation Limit to amount of solute that can be dissolved in solvent Limit to amount of solute that can be dissolved in solvent A solution is saturated when no more solute can be dissolved - reached equilibrium A solution is saturated when no more solute can be dissolved - reached equilibrium Add more solute and doesn’t dissolve Add more solute and doesn’t dissolve

Saturation Unsaturated solution has less than the max amount of solute that can be dissolved Unsaturated solution has less than the max amount of solute that can be dissolved Supersaturated solution has a greater amount of solute than needed to get a saturated solution Supersaturated solution has a greater amount of solute than needed to get a saturated solution

Concentration Ch.12 Section 3

Concentration of Solutions Concentration: amount of solute in a given amount of solvent or solution Concentration: amount of solute in a given amount of solvent or solution Concentrated: a lot of solute in solvent Concentrated: a lot of solute in solvent Dilute: small amt of solute in solvent Dilute: small amt of solute in solvent

Concentration of Solutions Most common unit is Molarity (M) Most common unit is Molarity (M) M = moles of solute M = moles of solute liters of solution liters of solution

Molarity Examples What is the molarity of a.100 L solution of NaOH if 10.0 g of NaOH were dissolved? What is the molarity of a.100 L solution of NaOH if 10.0 g of NaOH were dissolved? How many grams of CaCl 2 are needed to make a 1.00 M solution? How many grams of CaCl 2 are needed to make a 1.00 M solution? What volume is required to make a 3.0 M with 5.50 mol NaCl? What volume is required to make a 3.0 M with 5.50 mol NaCl?

Making Solutions How would you make 250 mL of 6.00 M NaOH solution? How would you make 250 mL of 6.00 M NaOH solution?

Concentration of Solutions Molality (m) Molality (m) m = moles of solute m = moles of solute kilograms of solvent What is the molality of a solution if 18.0 g C 6 H 12 O 6 (180. g/mol) is dissolved in 3.0 x 10 3 g of water? What is the molality of a solution if 18.0 g C 6 H 12 O 6 (180. g/mol) is dissolved in 3.0 x 10 3 g of water?

Solution Stoichiometry Limiting Reactant is Back!

Solution Stoichiometry Mix 2 aqueous sol’ns a rxn could occur Mix 2 aqueous sol’ns a rxn could occur If rxn occurs, get precipitate If rxn occurs, get precipitate Limiting Reactant controls amt of product Limiting Reactant controls amt of product BUT NOW… BUT NOW… Our reactants are not solids, we have AQUEOUS SOLUTIONS Our reactants are not solids, we have AQUEOUS SOLUTIONS How do we get moles of our reactants? How do we get moles of our reactants?

Getting Moles of Reactants Aqueous solutions are given in MOLARITY. Aqueous solutions are given in MOLARITY. Ex: 6 M = 6 moles of solute Ex: 6 M = 6 moles of solute 1 L of sol’n 1 L of sol’n Get Moles from Molarity!! Get Moles from Molarity!!

Example Zn(NO 3 ) 2 (aq) + Na 2 CO 3 (aq)  ZnCO 3 (s) + NaNO 3 (aq) Zn(NO 3 ) 2 (aq) + Na 2 CO 3 (aq)  ZnCO 3 (s) + NaNO 3 (aq) What mass of ppt can be formed when 50.0 mL of 2.0 M Zn(NO 3 ) 2 reacts with 35.0 mL of 2.0 M Na 2 CO 3 ? What mass of ppt can be formed when 50.0 mL of 2.0 M Zn(NO 3 ) 2 reacts with 35.0 mL of 2.0 M Na 2 CO 3 ? Write balanced equation: Write balanced equation: Find moles of each reactant: Find moles of each reactant: Convert moles of reactant  moles of ppt  mass of ppt Convert moles of reactant  moles of ppt  mass of ppt

Examples 0.55 g of ppt, Cu(OH) 2 is formed when excess CuSO 4 solution is mixed with 75.0 mL of NaOH solution. What is the concentration of NaOH? 0.55 g of ppt, Cu(OH) 2 is formed when excess CuSO 4 solution is mixed with 75.0 mL of NaOH solution. What is the concentration of NaOH? Write balanced equation: Write balanced equation: Find moles of NaOH: Find moles of NaOH: Calculate Molarity: Calculate Molarity:

Examples What volume of M HBr is required to react with 250 mL of 1.00 M NaOH? What volume of M HBr is required to react with 250 mL of 1.00 M NaOH? Balanced Equation Balanced Equation Find Moles NaOH  moles HBr Find Moles NaOH  moles HBr Use moles HBr  L of HBr Use moles HBr  L of HBr

Changing Concentration

1. Add more solvent Diluting the solution Diluting the solution Less concentrated solution Less concentrated solution 2. Decrease solvent/ Add solute Evaporation of solvent Evaporation of solvent Adding more solute Adding more solute More concentrated solution More concentrated solution

DILUTION Only use dilution when need concentration LESS THAN what you start with Only use dilution when need concentration LESS THAN what you start with M o V o = M n V n M o V o = M n V n M = molarity of total solution M = molarity of total solution V = volume of total solution V = volume of total solution Concentration has to be in molarity Concentration has to be in molarity Volume units just have to be the same! Volume units just have to be the same!

M o V o = M n V n You have 25.0 mL of a 10.0 M solution of NaCl. You only need it to be 2.50 M. What must your volume be to make this solution? You have 25.0 mL of a 10.0 M solution of NaCl. You only need it to be 2.50 M. What must your volume be to make this solution? How much water do you need to add? How much water do you need to add?

Ionic Reactions in Solutions Ch. 13

Ionic Solutions When water dissolves the solute, the ions of solute are hydrated When water dissolves the solute, the ions of solute are hydrated Ionic crystals that “trap” water with in themselves are hydrates Ionic crystals that “trap” water with in themselves are hydrates Ex: CuSO 4 5H 2 O Ex: CuSO 4 5H 2 O Copper(II) sulfate pentahydrate Copper(II) sulfate pentahydrate

Ionic Solutions Dissociation = when ions separate Dissociation = when ions separate NaCl(s)  Na +1 (aq) + Cl - (aq) NaCl(s)  Na +1 (aq) + Cl - (aq) If 1 mole of NaCl dissolves then 1 mole of each ion produced If 1 mole of NaCl dissolves then 1 mole of each ion produced Remember Molar Ratios!!! Remember Molar Ratios!!! CaCl 2 (s)  Ca +2 (aq) + 2Cl - (aq) CaCl 2 (s)  Ca +2 (aq) + 2Cl - (aq) 1 mol1 mol 2 mol 1 mol1 mol 2 mol H2OH2O H2OH2O

Ionic Solutions Not all ionic compounds are soluble in water Not all ionic compounds are soluble in water Table of Solubility Rules! Table of Solubility Rules! Can determine whether a compound will dissolve Can determine whether a compound will dissolve Soluble or Insoluble in water? Soluble or Insoluble in water? Copper(II) carbonate Copper(II) carbonate Sodium hydroxide Sodium hydroxide Silver chloride Silver chloride Potassium sulfate Potassium sulfate

Double-Replacement Rxns AX + BY  AY + BX AX + BY  AY + BX Mix two aqueous ionic solutions Mix two aqueous ionic solutions NaI (aq) + Pb(NO 3 ) 2(aq)  NaI (aq) + Pb(NO 3 ) 2(aq)  Products and their phases? Products and their phases? The solid formed during a reaction is the precipitate The solid formed during a reaction is the precipitate

Net Ionic Equations Def: An equation that shows only those compounds and ions that undergo a chemical change. Def: An equation that shows only those compounds and ions that undergo a chemical change. Ions that do not take part in the chemical reaction and are found in the solution before and after the reaction are spectator ions. Ions that do not take part in the chemical reaction and are found in the solution before and after the reaction are spectator ions.

Net Ionic Equations Rubidium phosphate + Titanium(IV) nitrate Rubidium phosphate + Titanium(IV) nitrate Ammonium sulfate + magnesium chloride Ammonium sulfate + magnesium chloride Calcium hydroxide + Cobalt(II) acetate Calcium hydroxide + Cobalt(II) acetate

Write the Complete ionic equation, the Net Ionic Equation and list the spectator ions for the following aqueous solutions: Write the Complete ionic equation, the Net Ionic Equation and list the spectator ions for the following aqueous solutions: Rubidium hydroxide + hydrochloric acid Rubidium hydroxide + hydrochloric acid Ammonium nitrate + Cesium phosphate Ammonium nitrate + Cesium phosphate Boron sulfate + Potassium hydroxide Boron sulfate + Potassium hydroxide Strontium chloride + Lead(II) nitrate Strontium chloride + Lead(II) nitrate