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Chapter 6: Sports Drink. 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?. Sports Drinks.
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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?
Sports Drinks • This chapter will introduce the chemistry needed to understand how Sports Drinks work • Section 6.1: Solutions & electrolytes • Section 6.2: Concentrations of solutions • Section 6.3: Acidity & pH • Section 6.4: Solubility & precipitates • Section 6.5: Stoichiometry • Section 6.7: Limiting Reactants • Section 6.6: Properties of solutions
Is a With How much solute is in it? Some affect that need to all dissolve when mixed together Can be determined by Sports Drinks Properties Differ from pure liquids in Solution Concentrations Electrolytes pH Titrations Solubility
Section 6.1—Solutions & Electrolytes What are those “electrolytes” they say you’re replacing by drinking sports drinks?
Dissolving substances • Substances are dissolved by a process called hydration • The solvent and solute need to break intermolecular forces within themselves • New intermolecular forces are formed between the solvent and solute • The solvent “carries off” the solute particles
- - O H H + Dissolving Ionic Compounds - + Ionic compound water Water 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. + - + - + -
- - + O + H H + Dissolving Ionic Compounds - + Ionic compound water As more ions are “exposed” to the water after the outer ions were “carried off”, more ions can be “carried off” as well. - - + - + -
- O H H + Dissolving Ionic Compounds - + Ionic compound water + - These free-floating ions in the solution allow electricity to be conducted - + - + - + -
Electrolytes • When 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.
+ - + Solute, sugar (polar) Solvent, water (polar) - - + - + - + - + - + Dissolving Covalent Compounds Polar covalent molecules are formed in the same way—water forms intermolecular forces with the solute and “carries” the solute particles away.
+ - + Solute, sugar (polar) Solvent, water (polar) - - + - + - + - + - + Dissolving Covalent Compounds However, the polar covalent molecules themselves do not split into charged ions—the solute molecule stays together and just separates from other solute molecules.
Non-electrolytes • When 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
Types of Electrolytes Non-Electrolytes Strong Electrolytes Weak Electrolytes Covalent Compounds Ionic compounds Ionic Compounds No molecules separate—ions are not formed Almost all ions are separated when dissolved in water. Only a few ions are separated when dissolved in water Does not conduct electricity at all when dissolved in water Easily conducts electricity when dissolved in water Conducts electricity slightly when dissolved in water
Breaking up Electrolytes • Leave polyatomic ions in-tact (including the subscript within the polyatomic ion) • All subscripts not within a polyatomic ion become coefficients • Be sure to include charges on the dissociated ions! Example: Break up the following ionic compounds into their ions KNO3 Ca(NO3)2 Na2CO3
Breaking up Electrolytes • Leave polyatomic ions in-tact (including the subscript within the polyatomic ion) • All subscripts not within a polyatomic ion become coefficients • Be sure to include charges on the dissociated ions! Example: Break up the following ionic compounds into their ions K+1 + NO3-1 Ca+2 + 2 NO3-1 2 Na+1 + CO3-2 KNO3 Ca(NO3)2 Na2CO3
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
Types of Solutions Super-Saturated Unsaturated Saturated Has more solute than would make a saturated solution dissolved More solute can be dissolved No more solute can be dissolved—it’s “full” In general, the higher the temperature of a solution, more solid can be dissolved.