Chapter 2: Chemistry Lecture Notes

Introduction to Chemistry

• Chemistry often evokes fear or apprehension.
• Goal: Reduce fear and increase understanding of chemistry.

Isotopes

• Isotopes: Variants of elements with different neutron numbers.
• **Hydrogen Isotopes: **
  • Standard Hydrogen: No neutrons.
  • Deuterium: 1 neutron.
  • Tritium: 2 neutrons.
• Some isotopes are radioactive (e.g., Carbon-14).

Solutions, Colloids, and Suspensions

• Solution: Particles are too small to see and don't settle (e.g., mineral water).
• Colloid: Particles can scatter light but don't settle (e.g., jello).
  • Jello can change form with temperature changes.
• Suspension: Large particles that scatter light and settle out (e.g., blood).
  • Blood separates when not moving.

Chemical Reactions and Reactivity

• Reactivity depends on electron configuration.
• Inert/Noble Gases: Helium and Neon are non-reactive.
• Reactivity Factors:
  • Electrical charge balance.
  • Fullness of electron shells.
• **Examples of Reactions: **
  • Salt in water: Mild reaction.
  • Vinegar and baking soda: Moderate reaction.
  • White phosphorus and water: Violent reaction.

Molecule Shapes and Covalent Bonds

• Molecule shape determined by bonds.
• Covalent Bonds:
  • Carbon Dioxide: Nonpolar double covalent bonds.
  • Water: Polar covalent bonds with distinct charges.

Types of Chemical Reactions

• Synthesis Reaction: Building larger molecules (often absorb energy).
• Decomposition Reaction: Breaking down molecules (often release energy).
• Exchange Reaction: Involves both synthesis and decomposition.

Acids, Bases, and pH

• pH Scale: 0-14; <7 is acidic, >7 is basic, 7 is neutral.
• Logarithmic scale: each unit is a 10x change.
• Acids: More hydrogen ions.
• Bases: More hydroxide ions.
• Body Buffers: Maintain stable pH by acting as either acids or bases.

Macromolecules and Dehydration Synthesis

• Carbohydrates, Proteins, Fats: Built via dehydration synthesis.
• Dehydration Synthesis: Water removal forms bonds.
• Carbohydrate Structure:
  • Monosaccharides, Disaccharides, Polysaccharides.
• Keto and Low-Carb Diets: Can lead to muscle breakdown.

Fats and Cholesterol

• Fats essential for cell membranes and hormones.
• Cholesterol: Necessary for hormone production.

Protein Structure

• Primary Structure: Chain of amino acids.
• Secondary, Tertiary, Quaternary Structures: Folding and coiling for function.

Enzymes

• Proteins that speed up reactions by lowering activation energy.
• Essential for efficient digestion and metabolism.

DNA Chemistry

• Complex molecule made of sugars, phosphates, proteins.
• Hydrogen bonds hold strands together.
• Chemistry helped deduce DNA's structure.

Conclusion

• Chemistry is complex but manageable.
• For questions, use the Unit 1 discussion board.