1.0 Introduction: Why Chemistry?

1.0 Introduction: Why Chemistry?

  • Chemistry is the study of matter and the changes it undergoes. Examples include:

    • the air we breathe

    • materials in our phones

    • the food we eat

  • Chemistry provides tools to understand both visible and invisible aspects of the world and to solve real-world problems by explaining phenomena such as:

    • why ice floats

    • how batteries store energy

    • what makes an acid "strong"

  • Chemistry is often called the central science because it connects a wide range of fields, including:

    • biology

    • medicine

    • environmental science

    • materials science
      -Chemists explore how matter behaves and changes, from molecular structures in our bodies to reactions powering batteries or water purification.

  • Chemistry will be part of the journey in most areas of science.

What Chemistry Will You See in This Course?

  • You will learn:

    • how atoms and molecules behave

    • how to describe and predict chemical reactions

    • how energy and equilibrium shape chemical processes

  • You will move between three ways of thinking about chemistry:

    • Macroscopic: what you can see or measure (e.g., colour changes, temperature, gas volume)

    • Microscopic: atoms, molecules, and ions (the invisible world driving those changes)

    • Symbolic: chemical formulas, equations, and calculations that connect the two

Three Ways of Thinking About Chemistry

  • Macroscopic domain (observable phenomena):

    • Examples: colour changes, temperature changes, changes in gas volume

    • What you can measure and see directly

  • Microscopic domain (the invisible world):

    • Focus: atoms, molecules, and ions

    • Explains the mechanisms behind macroscopic observations

  • Symbolic domain (formulas and equations):

    • Includes chemical formulas, balanced equations, and calculations

    • Connects macroscopic observations to microscopic behavior

Figure Description (Water in Three Domains)

  • (a) Macroscopic domain: examples include moisture in the air, icebergs, and the ocean—represent water at the visible level

  • (b) Microscopic domain: gas molecules are far apart and disorganized; solid water molecules are close together and organized; liquid water molecules are close together and disorganized

  • (c) Symbolic domain: the formula H₂O symbolizes water, and the symbols (g), (s), and (l) denote its phases (gas, solid, liquid)

  • Credit: the figure is a modified representation by a contributor (as noted in the caption: credit to “Gorkaazk”/Wikimedia Commons)

How to Use This Chapter

  • This chapter reviews key high school chemistry topics needed throughout the course.

  • Not everyone will need the same amount of study time:

    • If you’re confident in your background, skim the chapter and try the end-of-chapter problems first.

    • If you get stuck, go back to the relevant section for a refresher.

    • If chemistry feels new or challenging, work through the sections in order; each section builds on the last, with examples and practice to build confidence.

Licensing and Source Information

  • This page titled 1.0: Introduction is shared under a CC BY 4.0 license.

  • It was authored, remixed, and/or curated by OpenStax via LibreTexts, with edits to fit the LibreTexts platform style and standards.

Key Concepts and Takeaways

  • Chemistry as the study of matter and its changes, spanning everyday and advanced technologies.

  • The central role of chemistry across scientific disciplines and real-world problems.

  • The tripartite framework of macroscopic, microscopic, and symbolic representations to analyze and predict chemical phenomena.

  • The importance of visual (macroscopic), molecular (microscopic), and symbolic (equational) perspectives for a complete understanding.

  • The use of models and visuals (e.g., the H₂O example) to connect observable properties, molecular structure, and chemical formulas.

  • Practical study approach guidance: tailor your study pace to your background, build progressively, and leverage end-of-chapter problems for reinforcement.

Important Formulas and Notation

  • Molecular formula for water: extH2extOext{H}_2 ext{O}

  • Phase notations: (g),(s),(l)(g), (s), (l)

  • General idea: use symbolic representations to relate macroscopic observations to microscopic structure and dynamic processes

Connections to Other Lectures and Real-World Relevance

  • Chemistry connects to biology (biochemical processes), medicine (drugs, diagnostics), environmental science (pollution, water purification), and materials science (battery materials, polymers).

  • Understanding energy and equilibrium in chemical processes informs energy storage, material design, and sustainability decisions.

Ethical, Philosophical, and Practical Implications

  • The central role of chemistry in addressing societal challenges (energy, health, environment) emphasizes responsible science, data interpretation, and decision-making.

  • Critical thinking about how models (macroscopic, microscopic, symbolic) simplify reality and where they may fall short.

  • Accessibility of chemical knowledge (through open educational resources) supports equitable education and informed citizenship.