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Chapter 3: Matter and Energy: What Are the Building Blocks of Sustainability?

Introduction

• Antoine Lavoisier's Discovery (1772)

  • Showed that the total amount of substances remains constant during transformations—"Nothing is lost, nothing is created, everything is transformed."

• Influence of Matter and Energy on Environmental Choices

  • Forest fires impact wildlife, air quality, respiratory health, and contribute to climate change by releasing CO2.

• Importance of Understanding Matter and Energy

  • Critical for decision-making related to sustainability; knowledge helps identify sources of environmental problems and their solutions.

3.1 What Is Matter Anyway?

• Definition of Matter

  • Matter: Anything that occupies space and has mass. Comes in various forms: solids, liquids, gases, living/nonliving, human-made.

  • Matter is finite and composed of atoms.

• Elements and Atoms

  • Element: A substance that cannot be broken down (e.g., gold).

    • Of the 118 known elements, 90 exist in nature; others are lab-created.

  • Atom: The smallest unit of an element retaining the element's characteristics.

Components of an Atom

1. Protons

   • Positively charged particles; define the atomic number of an element.

2. Electrons

   • Negatively charged; orbit the nucleus in shells. An atom is electrically neutral if protons equal electrons. With an imbalance, it becomes an ion.

3. Neutrons

   • Neutral particles found in the nucleus.

   • Isotope: Variation of an element with a different number of neutrons (e.g., 15N vs. 14N).

3.2 What Distinguishes Different Kinds of Matter?

• Physical Properties Depend on:

  • The type of atoms involved, how they bond, and their arrangement.

• Molecules and Compounds

  • Molecule: Two or more atoms bonded together (e.g., O2).

  • Compound: A molecule consisting of atoms from two or more elements (e.g., H2O).

• Conservation of Mass

  • Law of conservation of mass: Matter cannot be created or destroyed; the mass remains unchanged despite chemical reactions and rearrangements of atoms.

3.3 How Do Atoms Bond Together?

• Bonding and Molecular Properties

  • The arrangement and connection of atoms dictate the properties of substances.

Types of Chemical Bonds

1. Ionic Bond

   • Strong bond formed when one atom donates electrons to another.

2. Metallic Bond

   • Electrons shared among metal atoms, allowing for malleability and conductivity.

3. Covalent Bond

   • Bonds when pairs of atoms share electrons; examples include N2, O2, and H2O.

4. Hydrogen Bond

   • Weak bond between a hydrogen atom (slight positive charge) and another atom with a negative charge; water molecules bond through hydrogen bonds due to polarity.

3.4 Acids and Bases

• Definitions:

  • Acids yield H+ ions in water; strong acids have higher concentrations than weaker ones.

  • Bases yield OH- ions in water; strong bases have higher OH- concentrations than weaker ones.

• pH Scale:

  • pH = 7 is neutral; < 7 is acidic; > 7 is basic.

  • Small pH changes can significantly impact ecosystems (e.g., CO2 increasing lake acidity).

3.5 Can Matter Change?

• Types of Changes

  • Matter can experience physical changes (phase changes) or chemical changes (reactions).

Phase Changes

1. Phase Change

   • Change in state (solid, liquid, gas) without altering chemical composition.

2. Molecular Movement

   • Solids: Atoms vibrate slowly in fixed shapes; attractively bonded.

   • Liquids: Atoms vibrate faster; have constant volume but adaptable shapes.

   • Gases: Atoms vibrate rapidly and randomly; no fixed volume or shape.

3.6 Chemical Reactions

• Chemical reactions allow molecules to convert into new substances.

  • Oxidation-reduction reactions (redox): involve electron transfer (oxidation = electron loss; reduction = electron gain).

  • Examples: Sugar oxidation in cells for energy production.

  • Polymerization: Smaller molecules link to form larger structures.

  • Depolymerization: Breaking down of biopolymers (e.g., marinating meat).

3.7 What Is Energy?

• Energy: Capacity to do work (applying force over distance).

Types of Energy

1. Kinetic Energy

   • Energy of motion (e.g., moving bird, car, rock).

2. Potential Energy

   • Stored energy (e.g., water in a dam, rock on a cliff).

3. Mechanical Energy

   • Can move objects, push, pull, or exert force.

4. Chemical Energy

   • Stored within atomic bonds; released during reactions (e.g., glucose).

5. Electrical Energy

   • Produced by moving electrons in conductive materials.

6. Radiant Energy

   • Energy from the sun; initiates photosynthesis in plants, algae, and some bacteria.

7. Nuclear Energy

   • Energy stored in atomic nuclei; includes nuclear fusion (fusing nuclei) and fission (splitting nuclei).

8. Geothermal Energy

   • Energy from Earth's core powering global processes.

3.8 What Happens to Energy When We Have Used It?

• Energy, like matter, is constant.

Laws of Thermodynamics

1. First Law

   • Energy cannot be created or destroyed; it can change forms.

2. Second Law

   • Energy transformations always degrade some energy (heat loss); leads to increasing entropy without energy input.

3.9 How Does Energy Affect Life?

• Food Chains and Trophic Levels

  • Organisms categorized by trophic levels—their position in the food chain.

  • Descriptions of levels: Primary producers (photosynthesis), primary consumers (herbivores), secondary consumers (carnivores/omnivores), tertiary consumers (meat-eaters), and decomposers.

• The 10% Law

  • Only 10% of energy transfers from one trophic level to the next; the rest is lost to heat, waste, and respiration.

• Higher trophic levels require more energy for biomass compared to lower levels.

3.10 What Can I Do?

1. Understand and Promote Sustainability

• Research companies with sustainable practices; advocate for environmentally friendly policies.

2. Volunteer for Sustainability Initiatives

• Engage with your school’s Office of Sustainability.

3. Adopt Recycling Practices

• Utilize recyclable materials (steel, paper, plastic).

4. Make Sustainable Choices

• Avoid products with pollutants; opt for sustainable alternatives.

5. Innovate in Sustainability

• Explore opportunities in green business and practices.