Chemistry Definition Flashcards

Chemistry Basics

• Chemistry explores the composition, structure, properties of matter, and its changes in different conditions.
• Matter is defined as any substance that occupies space and has mass.

Types of Chemistry

• Organic chemistry focuses on substances containing carbon.
• Inorganic chemistry studies substances that do not contain carbon but may have hydrogen.

Fundamental Concepts

• Elements are the simplest forms of chemical matter, indivisible without losing identity.
• Atoms are the smallest components of an element, maintaining its properties.
• Molecules result from the chemical combination of two or more atoms with definitive properties.
• Compounds are specific types of molecules formed by different elements.

Chemical vs. Physical Changes

• Chemical change alters a substance's composition, creating new products.
• Physical change modifies a substance's form or properties without creating a new substance.

Key Reactions

• Oxidation-reduction (redox) involves the transfer of oxygen, where the oxidizing agent is reduced, and the reducing agent is oxidized.
• Reduction is when oxygen is removed or hydrogen is added to a substance.
• Combustion is a rapid oxidation reaction yielding heat and light.

Properties of Substances

• A pure substance features a consistent composition with fixed properties.
• Solutions are stable mixtures of two or more substances, comprising a solute (dissolved) and a solvent (dissolving agent).
• Miscible liquids are mutually soluble, forming stable solutions, while immiscible liquids cannot combine in this manner.

Mixtures and Their Classification

• Suspensions feature undissolved particles in a liquid, making them unstable.
• Emulsions are mixtures of immiscible substances combined with an emulsifier, increasing stability.
• Surfactants help oil and water mix by reducing surface tension.

Specialty Chemicals

• Alkanolamines neutralize acids and adjust the pH in hair products.
• Volatile alcohols evaporate easily, while ammonia is a colorless gas made of hydrogen and nitrogen.
• Glycerin serves as a moisturizer and solvent in cosmetics, and silicones are used in conditioners and skin lubricants.

pH Scale

• pH, short for potential hydrogen, measures hydrogen ion concentration.
• Acidic solutions have a pH below 7, while alkaline solutions have a pH above 7, indicating their respective acidity or basicity.