Unit 6: TOXINS Solutions & Kinetics!

What do you think the word “solution” means in chemistry (not “solution” as in “answer”)? Discuss your ideas with the people at your group and then write your answer down.

Vocabulary Aqueous solution: solution where water is the solvent Solute Solvent substance which is dissolved The minority substance in the mixture dissolving substance The majority substance in the mixture Aqueous solution: solution where water is the solvent

Example: You have a beaker of 1000 mL of propanol and decide to dissolve some calcium chloride in it. Which is the solute? _______________ Which is the solvent? ______________ CaCl2 Propanol

Solvents Most of the time WATER is our solvent However, there are many important non-water solvents! Paint Thinner (Turpentine, C10H16) Nail Polish remover (Acetone, C3H6O) Dry cleaning (perchloroethylene,C2Cl4) *a carcinogen

MIXTURES! Mixture: Two or more substances mixed together that retain their original properties (in other words, no chemical bonds form between the two or more molecules)

Types of Mixtures “different” throughout the same throughout HOMOGENEOUS HETEROGENEOUS “different” throughout the same throughout SOLUTIONS are always homogeneous!

Shampoo? Homogeneous

Chunky Picante Salsa? Heterogeneous

Chex Mix? Heterogeneous

Salt water? Homogeneous

Summary Soluble Insoluble It dissolves. homogeneous- transparent solution Insoluble It doesn’t dissolve. heterogeneous- can have different “parts”

Remember . . . Like dissolves like. Polar Non-polar Polar substances will dissolve in _________ substances. Non-polar substances will dissolve in _____________ substances. Polar Non-polar New: Ionic substances will dissolve in POLAR substances.

No, iodine is non-polar and water is polar Would iodine crystals dissolve in water? No, iodine is non-polar and water is polar

Yes, iodine is non-polar and paint thinner is non-polar Would iodine crystals dissolve in paint thinner? Yes, iodine is non-polar and paint thinner is non-polar

Concentration: The amount of solute for a specified amount of solution. (A common measure of concentration is moles of solute per liter of solution (m/L).)

MOLARITY! Moles of solute Liters of solution

You have 8 moles of HCl and you pour it into 2 liters of water You have 8 moles of HCl and you pour it into 2 liters of water. What concentration of HCl did you produce? 8 moles HCl 4 mol/L OR 4 M = 2 liters solution

Which acid would you rather have spill on your arm?

1 mole/L would be less concentrated than 12 moles/L!

LABEL EACH MOLECULE AS POLAR COVALENT, NON-POLAR COVALENT or IONIC LABEL EACH MOLECULE AS POLAR COVALENT, NON-POLAR COVALENT or IONIC. Covalent: 2 or more non-metals Ionic: metal and a non-metal

Oil, C20H42 Ethanol, C2H6O NON-POLAR Covalent POLAR Covalent

Copper (II) Chloride, CuCl2 Calcium carbonate, CaCO3 IONIC IONIC

Molecular Structures Citric Acid, C6H8O6 POLAR Covalent

WARNING: ACTS NON-POLAR TODAY Molecular Structures Styrofoam Acetone, C3H6O NON-POLAR, Covalent POLAR, Covalent WARNING: ACTS NON-POLAR TODAY

Intermolecular Forces Review Intermolecular Forces: the attraction holding 2 or more molecules together Types: Dispersion, Dipole-Dipole, Hydrogen bonding Bonds: the force holding 2 or more atoms together within a molecule

Types of Inter-Molecular Forces (IMF) (see posters for review!) Dispersion: (weakest) found in non-polar molecules Dipole: (stronger) attracts polar molecules together Hydrogen bond: (strongest) molecules with O-H, N-H, or F-H bonds

Which substances dissolved in water? Non-polar molecules? vegetable oil, styrofoam Polar molecules? ethanol, citric acid Ionic compounds? copper chloride, calcium carbonate

Like dissolves Like Water is polar This means that a water molecule has both a positive and a negative side (these are the two “poles”) Water dissolves ionic and polar molecules best Ionic molecules contain positive and negative ions Polar molecules have positive and negative “sides”

Like dissolves Like Polar dissolves polar. Ethanol and water Nonpolar dissolves nonpolar. Hexane and oil Nonpolar will NOT dissolve with polar oil (nonpolar) and water (polar) will NOT mix

Dissolving an ionic solid in H2O NaCl (aq)  Na+ (aq) + Cl- (aq) The ions will break apart, each ion is attracted to the polar water molecules

When molecules dissolve… When molecules dissolve…. Intermolecular forces attract molecules to water http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/bio%20101/Bio%20101%20Lectures/chemistry/sodium%20ions,%20chloride%20ions,%20water%20molecules.gif

Note: when covalent molecules dissolve… Note: when covalent molecules dissolve…. The molecules do NOT break apart into individual atoms or ions http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/bio%20101/Bio%20101%20Lectures/chemistry/sodium%20ions,%20chloride%20ions,%20water%20molecules.gif

Nonpolar Compounds DO NOT dissolve in water Dipole attractions (between water molecules) http://www.iun.edu/~cpanhd/C101webnotes/aqueoussolns/images/genc3.jpg Non-polar substance (ex: oil)

How does soap work? Soap has both a POLAR/CHARGED part (attracts to water) NONPOLAR part (attracts to oil) So, soap allows us to “dissolve” oil in water and clean our hands! http://pathfinderscience.net/stain/img/Soapz.JPG http://www.chemistryland.com/CHM107/Water/Soap02.jpg