Chemical Matter and Its States

States of Matter

Matter is anything that occupies space and has mass. It exists in three primary states, each with distinct properties.

• Solid: Has a definite shape and volume.

• Liquid: Has a definite volume but no definite shape; takes the shape of its container.

• Gas: Has neither definite shape nor volume; expands to fill its container.

Additional info: These states are important in physiology, as body fluids and tissues can exist in different states under various conditions.

Energy and Its Forms

Definition and Types of Energy

Energy is the capacity to do work. In biological systems, energy is essential for all physiological processes.

• Kinetic Energy: Energy of motion; e.g., movement of muscles.

• Potential Energy: Stored energy; e.g., energy stored in chemical bonds.

• Chemical Energy: Potential energy stored in chemical bonds, such as ATP.

• Mechanical Energy: Energy involved in moving matter.

• Electrical Energy: Results from movement of charged particles (ions); important in nerve impulses.

• Radiant Energy: Energy that travels in waves; e.g., light energy used in vision.

Law of Thermodynamics: Energy can be converted from one form to another but cannot be created or destroyed.

Atomic Structure and Elements

Atoms and Subatomic Particles

Atoms are the basic units of matter, composed of subatomic particles:

• Protons: Positively charged particles found in the nucleus.

• Neutrons: Neutral particles found in the nucleus.

• Electrons: Negatively charged particles orbiting the nucleus.

Atomic Number: Number of protons in an atom; determines the element.

Mass Number: Sum of protons and neutrons in the nucleus.

Periodic Table: Organizes elements by atomic number and properties.

Common Elements in the Human Body

• Carbon (C)

• Oxygen (O)

• Nitrogen (N)

• Hydrogen (H)

• Calcium (Ca)

• Sodium (Na)

• Potassium (K)

• Phosphorus (P)

• Sulfur (S)

• Magnesium (Mg)

Additional info: These elements are essential for physiological functions such as bone structure, nerve conduction, and cellular metabolism.

Molecules, Compounds, and Mixtures

Definitions

• Molecule: Two or more atoms held together by chemical bonds.

• Element: Substance composed of atoms with the same atomic number.

• Compound: Substance formed from two or more different elements chemically bonded (e.g., H2O, CO2).

• Mixture: Combination of two or more substances physically intermixed, not chemically bonded.

Types of Mixtures:

• Solutions: Homogeneous mixtures; solute particles are evenly distributed and do not settle out (e.g., mineral water).

• Colloids: Heterogeneous mixtures with larger particles that do not settle out easily; often appear milky.

• Suspensions: Heterogeneous mixtures with large particles that settle out over time (e.g., blood cells in plasma).

Solution Properties

• Solvent: Substance present in the greatest amount; dissolves the solute.

• Solute: Substance present in lesser amount; dissolved by the solvent.

• Concentration: Amount of solute in a given amount of solvent; can be expressed as percent or molarity.

Percent Solution: Parts of solute per 100 parts of solution.

Molarity (M): Number of moles of solute per liter of solution.

Additional info: Molarity is commonly used in physiology to describe concentrations of ions and molecules in body fluids.

Summary Table: Comparison of Mixtures

Additional info: Understanding mixtures is important for interpreting laboratory results and physiological processes.