Chapter 1: Matter and Energy

Course Goals

This chapter introduces foundational concepts in chemistry and physics that are essential for understanding biological systems. Students will learn to classify matter, distinguish between types of energy, apply problem-solving frameworks, interpret chemical formulas, and express measurement uncertainty.

• Classify matter by physical and chemical properties.

• Distinguish between heat, work, potential energy, and kinetic energy.

• Apply the COAST method to problem solving.

• Interpret chemical formulas and what they represent.

• Express uncertainty in measurements using significant figures.

1.1: Exploring the Particulate Nature of Matter

Atoms: They Make Up Everything

Atoms are the fundamental building blocks of matter. The concept of atomism, proposed by Democritus, states that all matter is composed of tiny, indestructible units called atoms.

• Atom: The smallest particle of an element that retains the chemical identity of that element.

• Matter: Anything that has mass and occupies volume.

• Chemistry: The study of the composition, structure, and properties of matter.

Elements and the Periodic Table

Elements are pure substances that cannot be separated into simpler substances by chemical means. They are organized in the periodic table, which arranges elements by atomic number and properties.

• Element: A substance that cannot be separated into simpler substances by chemical processes.

• Periodic Table: A tabular arrangement of elements based on atomic number and recurring chemical properties.

• Compound: A substance composed of two or more elements chemically bonded in fixed proportions.

Compounds and Chemical Formulas

Compounds are represented by chemical formulas, which indicate the types and ratios of atoms present. For example, tin(II) oxide (SnO) and tin(IV) oxide (SnO2) differ in their ratios of tin to oxygen.

Example: Water (H2O) and hydrogen peroxide (H2O2) differ in their ratios of hydrogen to oxygen.

Mixtures

Mixtures are combinations of substances that can be separated by physical means. They are classified as homogeneous or heterogeneous based on uniformity.

• Homogeneous mixture: Uniform composition throughout (e.g., vinegar).

• Heterogeneous mixture: Non-uniform composition (e.g., salad dressing).

Example: Vinegar is a homogeneous mixture; salad dressing is heterogeneous.

1.2: COAST – A Framework for Solving Problems

The COAST Method

The COAST method is a structured approach to problem solving in science. It emphasizes careful analysis and logical reasoning.

1. Collect and Organize: Gather all relevant information, including units and assumptions.

2. Analyze: Determine relationships, write equations, and identify constants.

3. Solve: Perform calculations, check units, and ensure logical progression.

4. Think About It: Evaluate the plausibility of your answer.

Example: When calculating the mass of an atom, ensure the result is reasonable (e.g., an atom of gold should not weigh 30 grams).

1.3: Classes and Properties of Matter

Intensive vs. Extensive Properties

Properties of matter are classified based on their dependence on sample size.

• Intensive properties: Independent of sample size (e.g., density, ductility).

• Extensive properties: Dependent on sample size (e.g., mass, length).

Example: Gold's ductility is intensive; the length of gold wire produced is extensive.

Physical vs. Chemical Properties

Physical properties can be observed without changing the substance, while chemical properties involve the substance's ability to undergo chemical change.

• Physical properties: Shape, amount, ductility, malleability, density.

• Chemical properties: Reactivity, flammability, rate of reaction.

Example: The density of water is a physical property; its ability to react with sodium is a chemical property.

Key Definitions

• Bond: A force that holds two atoms or ions together in a molecule or compound.

• Molecule: A collection of chemically bonded atoms.

• Ion: An atom or molecule with a net electric charge.

Additional info: These definitions are foundational for understanding molecular biology and biochemistry.