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Chapter 24 Molecular Mixing. What is a molecule? Groups of atoms tightly bonded by covalent bonds Groups of atoms tightly bonded by covalent bonds Examples.

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Presentation on theme: "Chapter 24 Molecular Mixing. What is a molecule? Groups of atoms tightly bonded by covalent bonds Groups of atoms tightly bonded by covalent bonds Examples."— Presentation transcript:

1 Chapter 24 Molecular Mixing

2 What is a molecule? Groups of atoms tightly bonded by covalent bonds Groups of atoms tightly bonded by covalent bonds Examples water, oxygen, carbon dioxide Examples water, oxygen, carbon dioxide

3 Rule of Charges Opposites always attract Opposites always attract Like always repel Like always repel Atoms arrange themselves based on these two rules Atoms arrange themselves based on these two rules e.g. Na+ will tend to attract to Cl-, but Na+ tends to push away other Na+ ions

4 Ionic Bonds Charges are easily determined in ionic bonds…youve already done it…. Charges are easily determined in ionic bonds…youve already done it…. -atoms with 3 or more valence electrons want to lose, therefore they are + -atoms with 5 or more valence electrons want to gain, therefore they are – Na+Cl-

5 Covalent Bonds More difficult to determine charge More difficult to determine charge Many do not have a charge Many do not have a charge These are called NONPOLAR molecules These are called NONPOLAR molecules They share valence electrons equally They share valence electrons equally e.g. all the diatomic elements

6 Polar Molecules Comes from the word pole like on a magnet Comes from the word pole like on a magnet -opposite ends of a molecule have opposite charges. *Some atoms pull shared electrons harder than other…this property is called electronegativity *Fluorine pulls the hardest, then chlorine and oxygen.

7 Polar Molecules Atoms that pull the hardest on the electrons have more of a negative charge Atoms that pull the hardest on the electrons have more of a negative charge Atoms that pull the least on the shared electrons have more of a positive charge Atoms that pull the least on the shared electrons have more of a positive charge

8 The ability of Polar Molecules Polar molecules have the ability to dissolve ionic bonds because of the charges of the ends of the covalent molecules. Polar molecules have the ability to dissolve ionic bonds because of the charges of the ends of the covalent molecules. Water = red & white, Chlorine = green, Sodium = orange Water = red & white, Chlorine = green, Sodium = orange

9 Solubility A measure of how well a substance dissolves in another substance A measure of how well a substance dissolves in another substance Solvent- substance in the larger amount; does the dissolving Solvent- substance in the larger amount; does the dissolving Solute- substance in smaller amount; is dissolved Solute- substance in smaller amount; is dissolved In salt waterSalt is the solute, water is the solvent. In salt waterSalt is the solute, water is the solvent.

10 What makes something soluble? Salt mixes with water, oil does not. Salt mixes with water, oil does not. What is the difference? What is the difference? Remember our rule of charges: Remember our rule of charges: Opposites will _________________ Opposites will _________________ Like will _______________ Like will _______________

11 Solute/Solvent Relationships The rule of whether or not something will dissolve is simple: The rule of whether or not something will dissolve is simple: Like Dissolves Like Like Dissolves Like A Polar molecule will dissolve another polar molecule (salt and water) A Polar molecule will dissolve another polar molecule (salt and water) A nonpolar molecule will dissolve another nonpolar molecule (Nail polish and nail polish remover) A nonpolar molecule will dissolve another nonpolar molecule (Nail polish and nail polish remover)

12 Insoluble Substances that do not dissolve (like oil and water) are considered insoluble Substances that do not dissolve (like oil and water) are considered insoluble Oil is nonpolar(has no charge at all) Oil is nonpolar(has no charge at all) Water is polar(has a positive and negative end) Water is polar(has a positive and negative end) The water is attracted to itself more than to the oil so they will not mix. The water is attracted to itself more than to the oil so they will not mix.

13 What thing affect solubility? Polarity/Nonpolarity is the main one Polarity/Nonpolarity is the main one Temperature Increase Temperature Increase As things warm molecule movement increases As things warm molecule movement increases Makes things more likely to mix Makes things more likely to mix Pressure Increase Pressure Increase As things get pushed together As things get pushed together Makes things more likely to mix Makes things more likely to mix

14 Saturated vs. Unsaturated All substances can only mix so much. All substances can only mix so much. Once you put so much salt in water, that solution will not accept any more salt. Once you put so much salt in water, that solution will not accept any more salt. -It is said to be SATURATED Before it reaches that point, those water particles can still accept more salt, so it is said to be UNSATURATED Before it reaches that point, those water particles can still accept more salt, so it is said to be UNSATURATED

15 Soaps and Detergents How do soaps and detergents work on everything or do they? How do soaps and detergents work on everything or do they? There seems to be a cleaning agent for everything. There seems to be a cleaning agent for everything. Soaps and detergents have both polar and nonpolar parts, so they are able to dissolve either kind of dirt and grime. Soaps and detergents have both polar and nonpolar parts, so they are able to dissolve either kind of dirt and grime.


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