VWT 272 Class 5. Quiz 4. Number of quizzes taken 24 Min 8 Max 30 Mean 26.4 Median 29 Mode 30

Transcription

1 VWT 272 Class 5 Quiz 4 Number of quizzes taken 24 Min 8 Max 30 Mean 26.4 Median 29 Mode 30

2 Week 5 More Bonds, Acids, and Bases Let me embrace thee, sour adversity, for wise men say it is the wisest course. William Shakespeare ( )

3 Plan of Study Review Bonding Ionic Bonds Covalent Bonds Molecular Polarity Resonance Structures Two Ways to Model Acids Bases

4 Methanol - 6 Ways

5 Opposites Attract Ionic Bonding Na + Cl Na + + Cl - NaCl

6 Opposites Attract Ionic Bonding Na + Cl Na + + Cl - NaCl

7 Opposites Attract Ionic Bonding Is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. (Wikipedia)

8 Sharing is Caring Covalent Bonding Cl + Cl ClCl Cl 2

9 Sharing is Caring Covalent Bonding Cl + Cl ClCl Cl 2

10 Sharing is Caring Covalent Bonding H + Cl HCl

11 Sharing is Caring Covalent Bonding 2H + O H 2 O

12 Polar Covalent Bonds Middle ground between Ionic and Covalent Bonds

13 Electronegativity If the difference is between 0.0 and 0.4 non-polar covalent bond If the difference is between 0.4 and 1.7 polar covalent bond If the difference is > 1.7 ionic bond

14 Polar Bonds and Polar Molecules Cl 2 Cl has an electronegativity of 3.0 Cl has an electronegativity of 3.0 So bond is Non-Polar Covalent Electrons and charge are equally distributed around the molecule Molecule is Nonpolar

15 Polar Bonds and Polar Molecules Carbon Tetrachloride CCl 4 Cl has an electronegativity of 3.0 C has an electronegativity of 2.5 So bonds are Polar Covalent Partial charge is equally distributed around the molecule Molecule is Nonpolar

16 Polar Bonds and Polar Molecules Chloroform CHCl 3 Cl has an electronegativity of 3.0 C has an electronegativity of 2.5 H has an electronegativity of 2.1 So all bonds are Polar Covalent Partial charge is NOT equally distributed around the molecule Molecule is Polar

17 Polar Bonds and Polar Molecules Carbon Tetrachloride vs. Chloroform δ+ δ-

18 Water a Polar Covalent Molecule

19 Resonance Structures When more than 1 valid Lewis dot structure can be drawn. NO 2- (Nitrite) N has 5 valence electrons = 5 O has 6 valence electrons = 2 x 6 = 12 Negative ion (cation) = 1 18 valence electrons

20 Resonance Structures NO 3- (Nitrate) N has 5 valence electrons = 5 O has 6 valence electrons = 18 Negative ion (cation) = 1 24 valence electrons

21 Resonance Structures O 3 (Ozone) O has 6 valence electrons = 18 SO 3 2- (Sulfite ion) CO 3 2- (Carbonate ion) C 3 H 5 1- (Allyl ion) SCN 1- (Thiocyanate ion) Fewest multiple bonds Most favored form - charge on the most electronegative atom

22 A Brief Taste of Nomenclature Solids Au (s), NaCl (s) Liquids Br (l), C 2 H 5 OH(l) Gas He (g), C 2 H 2 (g)

23 Hydrogen Atoms, Ions, & Protons H H + + e -

24 Hydrogen Ions & Hydronium Ions The Shame of Lazy Chemists

25 Acids & Bases Two ways to look at acids and bases Arrhenius Bronsted-Lowry Acids Sting in cuts Turns blue litmus paper red Turns phenolphthalein colorless Bases Feel slippery Turns red litmus paper blue Turns phenolphthalein pink

26 Arrhenius Acids & Bases Svante Arrhenius ( ) Sweden Theory of Ionic Disassociation solid crystalline salts disassociate into paired charged particles (ions) when dissolved in water Acids produce hydrogen ions (H + ) when dissolved in water Bases produce hydroxide ions (OH - ) when dissolved in water Developed the concept of Greenhouse Effect due to CO 2 in the Atmosphere Won Nobel Prize for Chemistry in 1903

27 Arrhenius Acids & Bases Arrhenius Acid is a compound that increases the concentration of H + ions when added to water. Arrhenius Base is a compound that increases the concentration of OH - ions when added to water. Salt is a compound that produces ions other than H + and OH - when dissolved in water

28 Arrhenius Acids & Bases Arrhenius Acid is a compound that increases the concentration of H + ions when added to water. H + = proton = H 3 O + = hydronium ion

29 Arrhenius Acids & Bases Arrhenius Acid is a compound that increases the concentration of H + ions when added to water. HCl dissolved in water HCl (aq) + H 2 O (l) H 3 O + (aq) + Cl - (aq) HCl (aq) H + (aq) + Cl - (aq) HCl (aq) H + + Cl -

30 Arrhenius Acids & Bases Arrhenius Base is a compound that increases the concentration of OH - ions when added to water. NaOH dissolved in water NaOH (s) + H 2 O (l) Na + (aq) + OH - (aq) NaOH (aq) Na + (aq) + OH - (aq) NaOH (aq) Na + + OH -

31 Brønsted-Lowry Acids & Bases Brønsted-Lowry Acid is a Proton Donor Brønsted-Lowry Base is a Proton Acceptor HCl + NH 3 NH 4+ + Cl - B/L Base B/L Acid

32 Brønsted-Lowry Acids & Bases Brønsted-Lowry Acid is a Proton Donor Brønsted-Lowry Base is a Proton Acceptor HCl + H 2 O H 3 O + + Cl - B/L Acid B/L Base

33 Brønsted-Lowry Acids & Bases Bronsted-Lowry Acid is a Proton Donor Bronsted-Lowry Base is a Proton Acceptor HCl + H 2 O H 3 O + + Cl -

34 Water is AMAZING! Water can be either a Bronsted-Lowry Acid or a Bronsted-Lowry Base! Amphoteric Water can be BOTH a Bronsted-Lowry Acid or a Bronsted-Lowry Base at the same time!

35 Next Week The Mole Molariety Concentration Density Brix Baume Plato