Chapter 1: Matter, Measurement, and Problem Solving – Structured Study Notes

Chapter 1: Matter, Measurement, and Problem Solving

Introduction to Chemistry

Chemistry is the science that seeks to understand the behavior of matter by studying the properties and interactions of atoms and molecules. The central idea in chemistry is that the properties of matter are determined by the properties of its constituent atoms and molecules.

• Matter: Anything that occupies space and has mass.

• Atoms: The fundamental building blocks of matter.

• Molecules: Groups of atoms bonded together in specific arrangements.

Atoms and Molecules

The behavior and properties of matter are dictated by the types and arrangements of atoms and molecules.

• Atoms are submicroscopic particles that make up all ordinary matter.

• Free atoms are rare; they usually bond to form molecules with specific geometries.

• Example: Water molecules (H2O) consist of two hydrogen atoms and one oxygen atom held together by chemical bonds.

• Small differences in atomic or molecular structure can result in large differences in substance properties (e.g., graphite vs. diamond, both made of carbon).

The Scientific Approach to Knowledge

Scientific knowledge is empirical, based on observation and experiment. The scientific method is a systematic process for understanding nature.

• Observation: Gathering data about nature's characteristics or behavior.

• Hypothesis: A tentative explanation of observations; must be falsifiable.

• Experimentation: Testing hypotheses through controlled procedures.

• Law: A brief statement summarizing past observations and predicting future ones (e.g., Law of Conservation of Mass: "In a chemical reaction, matter is neither created nor destroyed.").

• Theory: A well-substantiated model explaining why nature behaves as it does (e.g., Dalton's atomic theory).

Classification of Matter

Matter can be classified by its physical state and its composition.

• States of Matter: Solid, liquid, and gas.

• Solids: Atoms/molecules are closely packed in fixed positions; solids have fixed volume and shape.

• Crystalline solids: Atoms/molecules arranged in long-range, repeating patterns (e.g., diamond, table salt).

• Amorphous solids: Atoms/molecules lack long-range order (e.g., glass, plastic).

• Liquids: Atoms/molecules are close but can move past each other; liquids have fixed volume but not fixed shape.

• Gases: Atoms/molecules are far apart and move freely; gases are compressible and have neither fixed volume nor shape.

Classification by Composition

Matter is also classified as pure substances or mixtures.

• Pure Substance: Composed of only one component; composition is invariant.

• Element: Cannot be chemically broken down into simpler substances; consists of one type of atom.

• Compound: Composed of two or more elements in fixed proportions; can be broken down into elements.

• Mixture: Composed of two or more components in variable proportions.

• Heterogeneous Mixture: Composition varies from one region to another (e.g., sand and salt mixture).

• Homogeneous Mixture: Uniform composition throughout (e.g., sweetened tea).

Separating Mixtures

Mixtures can be separated by exploiting differences in physical or chemical properties.

• Decanting: Pouring off a liquid from a solid-liquid mixture (e.g., sand and water).

• Distillation: Heating a liquid mixture to boil off the more volatile component, which is then condensed and collected.

• Filtration: Separating an insoluble solid from a liquid by passing the mixture through filter paper.