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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.

  1. Volunteer for Sustainability Initiatives

  • Engage with your school’s Office of Sustainability.

  1. Adopt Recycling Practices

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

  1. Make Sustainable Choices

  • Avoid products with pollutants; opt for sustainable alternatives.

  1. Innovate in Sustainability

  • Explore opportunities in green business and practices.