Grade 12 Physical Sciences Study Guide: Paper 2 H

Grade 12 Physical Sciences Cheat Sheet: Paper 2 H

Introduction

• Author: Miss Angler, S. Burger
• Published: 2024
• Proof Reader: N. Holm

Contents Page

• Tips for Success - Page 4
• Organic Chemistry: Nomenclature - Page 18
• Organic Chemistry: Intermolecular Forces - Page 68
• Organic Reactions - Page 83
• Rate and Extent of Reaction - Page 101
• Chemical Equilibrium - Page 124
• Acids and Bases - Page 155
• Electrochemistry - Page 181

Tips for Success (100%)

• Periodic Table of Elements
  • Lists all known elements: 118 elements to date.
  • Arranged by increasing atomic number (number of protons).
  • Groups: 18 vertical columns (similar chemical properties).
  • Periods: 7 horizontal rows.

Charge and Groups

Diatomic Molecules

• Certain elements exist as diatomic molecules:
  1. H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂
• 'di' = two.

Naming Compounds

Monoatomic Ions

• Metal and non-metal: Metal first, non-metal suffix -ide.
• Example: NaBr = Sodium bromide.

Polyatomic Ions

• Common names and charges of essential polyatomic ions:
  • Hydroxide: OH^-
  • Sulphate: SO₄^2-
  • Phosphate: PO₄^3-
  • Ammonium: NH₄⁺

Chemical Formula Writing

1. Neutral compound: Total charge = 0.
2. Use the Crossover Rule to write formulas of ionic compounds by crossing over the charges.

Elements with Varying Valencies

• Transition metals display various charges indicated using Roman numerals.
  • Example: Iron (II) = Fe²⁺, Iron (III) = Fe³⁺.

Organic Chemistry

Definitions and Key Points

• Organic Molecules: Contain carbon.
• Molecular Formula: (C₃H₈) indicates atomic composition.
• Functional Groups: Affect chemical and physical properties (e.g., -OH in alcohols).
• Isomers: Same molecular formula, different structures (Structural Isomers, Chain Isomers, Positional Isomers).

Common Organic Reactions

• Combustion: Rapid reaction with oxygen.
• Esterification: Formation of esters from an alcohol and carboxylic acid.
• Substitution Reactions: Replacement of functional groups in organic compounds.
• Addition Reactions: Unsaturated compounds react to become saturated.

Rate and Extent of Reaction

Factors Affecting Reaction Rate

• Concentration: Higher concentration=more particles=greater chance of collisions.
• Temperature: Increased temperature=more energy=more effective collisions.
• Surface Area: Greater surface area=more exposure to reactants and collisions.
• Catalyst: Lowers activation energy, increasing reaction rate.

Chemical Equilibrium

Key Concepts

1. Dynamic Equilibrium: Rate of the forward reaction equals the rate of the reverse reaction.
2. Le Chatelier's Principle: If a system at equilibrium is disturbed, it shifts to counteract the disturbance.
3. Equilibrium Constant (K_c): Ratio of concentrations of products to reactants at equilibrium.
   • $K_c = \frac{[C]^{c}[D]^{d}}{[A]^{a}[B]^{b}}$
   • Only gases and aqueous solutions included in $K_c$ expression.

Acids and Bases

Properties

• Strong Acids (HCl, H₂SO₄): Completely ionize in water.
  - Weak Acids (CH₃COOH): Incompletely ionize in water.
  - Indicators: Change color in response to pH changes (e.g., phenolphthalein, bromothymol blue).
  

Reactions

• Neutralization: Reaction between an acid and a base forms salt and water.

Electrochemistry

Key Concepts

1. Galvanic Cells: Convert chemical energy to electrical energy via spontaneous REDOX reactions.
   • Anode: Oxidation occurs, negatively charged.
   • Cathode: Reduction occurs, positively charged.
2. Electrolytic Cells: Convert electrical energy to chemical energy; non-spontaneous reactions.
   • Anode is positive, cathode is negative.

Conclusion

• Review: Master definitions, molecular structures, and formula writing are core to understanding scientific principles in organic chemistry and require an emphasis on thorough practice and understanding.