Chemistry Review: Nomenclature, Molar Mass, and Chemical Reactions

Course Logistics and Preparation for Test 1

• Homework Assignments: Students should utilize Homework 1 and Homework 2 as primary study materials to prepare for Test 1.

• Test 1 Schedule:

  • Opening Date: Friday, the 4th.

  • Closing Date: Sunday.

  • Timeframe: The test remains open for the duration of that weekend.

• Future Course Schedule:

  • Wednesday: Discussion on stoichiometry, percent yield, types of reactions, and oxidation-reduction.

  • Friday: Wrap up General Chemistry and begin Organic Chemistry.

  • Following Monday: Continue Organic Chemistry.

  • Following Wednesday: Complete Organic Chemistry and conduct a Test 1 review.

  • Following Friday: Test 1 occurs. Regular classes will continue with Unit 2 material, which will be recorded and posted for later viewing.

• Primary Rule: Identify if the compound is ionic or covalent.

• Ionic Indicators:

  • Presence of a metal or a polyatomic ion.

• Covalent Indicators:

  • No metal or polyatomic ion; consists of nonmetals.

• Naming Differences:

  • Ionic names lack prefixes and may use Roman numerals for transition metals.

  • Covalent names use prefixes to denote the number of atoms.

Ionic Nomenclature: Names and Formulas

• Roman Numerals:

  • Required for transition metals (Group B), Tin ($Sn$), and Lead ($Pb$ ).

  • Not for Group 1A, 2A, or Aluminum ($Al^{3+}$).

• Roman Numeral Determination Example: For $CrO$, Oxygen has a $-2$ charge; thus, Chromium must be $+2$, resulting in "Chromium (II) oxide."

• Charge Patterns:

  • Group 1A: $+1$, 2A: $+2$, Aluminum: $+3$, 5A: $-3$, 6A: $-2$, 7A: $-1$, Noble Gases: Neutral.

• Writing Formulas Example: Iron (III) sulfide as $Fe_2S_3$ (swap charges).

Polyatomic Ions and Subscripts

• Key Polyatomic Ions: Phosphate ($PO_4^{3-}$), Ammonium ($NH_4^{+}$), Carbonate ($CO_3^{2-}$), Nitrate ($NO_3^{-}$), Sulfate ($SO_4^{2-}$).

• Naming: $Mg_3(PO_4)_2$ is "Magnesium phosphate."

• Example Formula: Ammonium carbonate as $(NH_4)_2CO_3$.

Covalent Bond Definitions and Nomenclature

• Ionic Bond: Transfer of electrons, creating charged ions.

• Covalent Bond: Sharing of electrons between nonmetals.

• Subscripts in Covalents: Based on prefixes used in naming.

Greek Prefixes and Naming Rules

• Prefixes (1-10):

  • 1: Mono, 2: Di, 3: Tri, 4: Tetra, 5: Penta, 6: Hexa, 7: Hepta, 8: Octa, 9: Nona, 10: Deca.

• Covalent Naming Rules: "Mono-" is omitted for the first element.

Acid Chemistry and Nomenclature

• Acid Characteristics: Start with Hydrogen ($H$) and release hydrogen ions in water.

• Naming Rules:

  • Without Oxygen: Use "hydro-" and change to "-ic" (e.g., $HCl$: Hydrochloric acid).

  • With Polyatomic Ion: Change the suffix (e.g., $HNO_3$: Nitric acid).

• Writing Formulas: Example: Phosphoric acid as $H_3PO_4$.

The Mole Concept and Avogadro's Number

• Mole Concept: A counting unit for atoms/molecules, analogous to a dozen.

• Avogadro’s Number: $6.02 \times 10^{23}$ particles in one mole.

Molar Mass Calculations

• Definition: The mass of one mole of a substance (grams or AMU).

• Total Molar Mass Calculation Example: For Glucose ($C_6H_{12}O_6$), it totals $180.12 \text{ g/mol}$.

Questions & Discussion

• Visualizing a Mole: The speaker describes an anecdote about a cat bringing a biological mole into the house, but clarifies the chemical mole is a mathematical concept.

• Career/Lab Application: The speaker shares personal experience working in medicinal chemistry at Auburn, synthesizing compounds as potential drugs for Glaucoma. These products of chemical reactions were then sent to other labs for testing.

• Cooking Analogy: Chemistry is compared to cooking. Reactants are ingredients (measured in moles instead of cups/teaspoons), and the product is the meal. If ingredients are not measured correctly (stoichiometry), the reaction/recipe fails.