Chapter 6 Notes: Solutions, Acids and Bases Chapters 22: Solutions Section 1: How Solutions Form Mrs. Chilton

A. Solutions and Other Mixtures All matter is either a pure substance or a mixture Types of mixtures Homogeneous = solution; same composition throughout Heterogeneous = not the same composition throughout Pure substances Elements Compounds

B. Solutions Solution is a homogeneous mixture Made up of solute and solvent Solute = what is dissolved Solvent = substance doing the dissolving Most common solvent? Water! Why?

B. Solution Examples KoolAid Unsweet tea Sweetened tea Saltwater

C. Dissolving Molecules are constantly in motion according to… Kinetic Theory of Motion When particles collide, energy is transferred When ionic compounds dissolve in water, ions separate in solution Example: NaCl in water becomes Na+ and Cl-

D. Solvents Water is universal solvent b/c of its polarity If something can dissolve in something else, it is said to be soluble If it cannot dissolve, it is said to be insoluble “Like dissolves like”

D. Solvents “Like Dissolves Like” NONPOLAR POLAR

E. Solvation First... Then... Solvation – the process of dissolving solute particles are surrounded by solvent particles First... solute particles are separated and pulled into solution Then...

NaCl(s)  Na+(aq) + Cl–(aq) E. Solvation Dissociation separation of an ionic solid into aqueous ions NaCl(s)  Na+(aq) + Cl–(aq)

E. Solvation Non- Electrolyte Weak Electrolyte Strong Electrolyte + sugar - + acetic acid - + salt Non- Electrolyte Weak Electrolyte Strong Electrolyte solute exists as molecules only solute exists as ions and molecules solute exists as ions only

F. Factors Affecting Solubility Solubility = amount of a substance that will dissolve in a liquid Smaller pieces of a substance dissolve faster b/c of larger surface area Stirring or shaking speeds dissolving b/c particles are moving faster and colliding more Heating speeds dissolving (see above) Not all substances dissolve

F. Solubility Solids are more soluble at... high temperatures. Gases are more soluble at... low temperatures & high pressures (Henry’s Law). EX: nitrogen narcosis, the “bends,” soda

G. Solubility Solubility Curves maximum grams of solute that will dissolve in 100 g of solvent at a given temperature varies with temp based on a saturated soln

G. Solubility Solubility Curve shows the dependence of solubility on temperature

HNO3(aq) + H2O(l)  H3O+(aq) + NO3–(aq) B. Solvation Ionization breaking apart of some polar molecules into aqueous ions HNO3(aq) + H2O(l)  H3O+(aq) + NO3–(aq)

B. Solvation C6H12O6(s)  C6H12O6(aq) Molecular Solvation molecules stay intact C6H12O6(s)  C6H12O6(aq)

B. Solvation Soap/Detergent polar “head” with long nonpolar “tail” dissolves nonpolar grease in polar water

H. Concentration The more solute or less solvent in a solution, the more concentrated the solution becomes The less solute or more solvent in a solution, the more dilute the solution becomes A saturated solution is one in which no more solute can dissolve A supersaturated solution is one in which the solvent is heated and can dissolve more solute

H. Concentration UNSATURATED SOLUTION more solute dissolves no more solute dissolves SUPERSATURATED SOLUTION becomes unstable, crystals form concentration

Chapter 23 Acids, Bases & Salts

Review – Acid Names HCl H2SO4 HNO3 H2SO3 HC2H3O2 Hydrochloric acid Sulfuric acid Nitric acid Sulfurous acid Acetic acid

What are acids? Compounds that donate H+ ions in water Taste sour Concentrated acids can burn skin and eyes On pH scale, found below 7 Stronger acids closer to 1 Examples: citric acid, stomach acid, soda, coffee

What are bases? Compounds that donate OH- ions in water Taste bitter, are slippery Can be dangerous as well Often cleaning products pH above 7 Stronger bases closer to 14 Examples: bleach, baking soda, antacids

Neutral All neutral solutions have a pH of 7 Water is a neutral solution

pH Scale

HCl + NaOH  H2O + NaCl Neutralization Example: Reaction between an acid and a base to produce water and a salt H+ + OH-  H2O Example: HCl + NaOH  H2O + NaCl Do not always produce a neutral solution

Indicators Chemical dyes whose color are affected by acidic and basic solutions are called acid-base indicators

Summary BASES ACIDS electrolytes  electrolytes sour taste bitter taste turn litmus red turn litmus blue Donate H+ (HCl) Donate OH- (NaOH) vinegar, milk, soda, apples, citrus fruits ammonia, lye, antacid, baking soda