2 Introductory Activity What do you think are the benefits of drinking a sports drink while exercising rather than plain water?How are your ideas influenced by the marketing strategies of the companies that sell these drinks?
3 Sports DrinksThis chapter will introduce the chemistry needed to understand how Sports Drinks workSection 6.1: Solutions & electrolytesSection 6.2: Concentrations of solutionsSection 6.3: Acidity & pHSection 6.4: Solubility & precipitatesSection 6.5: StoichiometrySection 6.7: Limiting ReactantsSection 6.6: Properties of solutions
4 Sports Drinks Properties Solution Concentrations Electrolytes pH Is aPropertiesDiffer from pure liquids inSolutionHow much solute is in it?WithConcentrationsElectrolytesSome affectCan be determined bythat need to all dissolve when mixed togetherpHSolubilityTitrations
5 Section 6.1—Solutions & Electrolytes What are those “electrolytes” they say you’re replacing by drinking sports drinks?
6 Dissolving substances Substances are dissolved by a process called hydrationThe solvent and solute need to break intermolecular forces within themselvesNew intermolecular forces are formed between the solvent and soluteThe solvent “carries off” the solute particles
7 Dissolving Ionic Compounds +-OH-+Ionic compoundwaterWater molecules are polar and they are attracted to the charges of the ions in an ionic compound.-+-When the intermolecular forces are stronger between the water and the ion than the intramolecular between the ions, the water carries away the ion.+-+-+-
8 Dissolving Ionic Compounds +-OH-+Ionic compoundwater-As more ions are “exposed” to the water after the outer ions were “carried off”, more ions can be “carried off” as well.+-+-+-+-
9 Dissolving Ionic Compounds +-OH-+Ionic compoundwater+-These free-floating ions in the solution allow electricity to be conducted-+-+-+-
10 ElectrolytesWhen there are free-floating charges in a solution then it can conduct electricity.Things that produce free-floating charges when dissolved in water are called electrolytes.
11 Dissolving Covalent Compounds Solvent, water (polar)+-- +Solute, sugar (polar)Polar covalent molecules are formed in the same way—water forms intermolecular forces with the solute and “carries” the solute particles away.- +- +- +
12 Dissolving Covalent Compounds Solvent, water (polar)+-- +Solute, sugar (polar)- +However, the polar covalent molecules themselves do not split into charged ions—the solute molecule stays together and just separates from other solute molecules.
13 Non-electrolytesWhen molecules separate from other molecules (breaking intermolecular forces), but free-floating charges are not produced from breaking intramolecular forces, the solution cannot conduct electricity.These are called non-electrolytes
14 Types of Electrolytes Strong Electrolytes Weak Electrolytes Non-ElectrolytesIonic compoundsIonic CompoundsCovalent CompoundsAlmost all ions are separated when dissolved in water.Only a few ions are separated when dissolved in waterNo molecules separate—ions are not formedEasily conducts electricity when dissolved in waterConducts electricity slightly when dissolved in waterDoes not conduct electricity at all when dissolved in water
15 Breaking up Electrolytes Leave polyatomic ions in-tact (including the subscript within the polyatomic ion)All subscripts not within a polyatomic ion become coefficientsBe sure to include charges on the dissociated ions!Example:Break up the following ionic compounds into their ionsKNO3Ca(NO3)2Na2CO3
16 Breaking up Electrolytes Leave polyatomic ions in-tact (including the subscript within the polyatomic ion)All subscripts not within a polyatomic ion become coefficientsBe sure to include charges on the dissociated ions!Example:Break up the following ionic compounds into their ionsKNO3Ca(NO3)2Na2CO3 K+1 + NO3-1 Ca NO3-1 2 Na+1 + CO3-2
17 Misconceptions about dissolving People often describe something that dissolves as having “disappeared”Before the solute dissolves, it’s in such a large group of particles that we can see it.After dissolving, the solute particles are still there—they’re just spread out throughout the solution and are in groupings so small that our eyes can’t see them
18 Types of Solutions Unsaturated Saturated Super-Saturated More solute can be dissolvedNo more solute can be dissolved—it’s “full”Has more solute than would make a saturated solution dissolvedIn general, the higher the temperature of a solution, more solid can be dissolved.