Matter, States, Properties, and Energy in Chemistry

스터디 가이드 - 스마트 노트

자료에 맞춘 맞춤형 노트, 핵심 정의, 예시, 맥락을 확장해 제공합니다.

Matter is anything that occupies space and has mass. All physical objects, substances, and materials are forms of matter.

Atoms: The fundamental building blocks of matter. Each element consists of a unique type of atom.
Molecules: Groups of two or more atoms bonded together. Molecules can consist of the same or different types of atoms.

Example: A water molecule (H2O) consists of two hydrogen atoms and one oxygen atom bonded together.

Solid: Has a fixed shape and volume. Particles are tightly packed and only oscillate in place.
Liquid: Has a fixed volume but no fixed shape. Particles are close together but can move past one another.
Gas: Has neither fixed shape nor fixed volume. Particles are far apart and move freely.

Crystalline: Atoms or molecules are arranged in geometric patterns with long-range repeating order (e.g., table salt, diamonds).
Amorphous: Atoms or molecules lack long-range order (e.g., glass, plastic).

Pure Substance: Composed of only one type of atom or molecule. Examples include elements (like gold) and compounds (like water).
Mixture: Composed of two or more different substances combined in variable proportions.

Element: A substance that cannot be broken down into simpler substances by chemical means. Each element is made of one kind of atom.
Compound: A substance made of two or more elements chemically bonded together in fixed proportions.

Heterogeneous Mixture: The composition is not uniform throughout; different parts can be distinguished (e.g., salad, sand in water).
Homogeneous Mixture: The composition is uniform throughout; appears as a single substance (e.g., saltwater, air).

Physical Property: Can be observed or measured without changing the substance's composition (e.g., color, melting point, density).
Chemical Property: Can only be observed by changing the substance's composition (e.g., flammability, reactivity).

Physical Change: Alters the appearance or state of matter without changing its composition (e.g., melting, freezing, dissolving).
Chemical Change: Alters the composition of matter, resulting in new substances (e.g., burning, rusting).

Chemical Reaction: A process in which substances (reactants) are transformed into different substances (products) through chemical changes.
Reactants: Substances present before the reaction.
Products: Substances formed as a result of the reaction.

Decanting: Carefully pouring off a liquid from a mixture to separate it from a solid or another liquid.
Distillation: Separates and purifies liquids by heating them to form vapor and then cooling the vapor back into liquid.
Filtration: Separates solids from liquids by passing the mixture through filter paper.

Volatile: A substance that is likely to vaporize or change suddenly, often used in the context of distillation.

Law of Conservation of Mass: Matter is neither created nor destroyed in a chemical reaction.
Law of Conservation of Energy: Energy is neither created nor destroyed; it can only be transformed from one form to another.

Energy: The capacity to do work.
Work: The result of a force acting through a distance.
Kinetic Energy: Energy associated with motion.
Potential Energy: Energy stored due to position or composition.
Electrical Energy: Energy from the flow of electric charge.
Thermal Energy: Energy from the random motion of atoms and molecules; related to heat.
Chemical Energy: A form of potential energy stored in the positions of particles within a chemical system.

Kilowatt-hour (kWh): A unit of energy commonly used for electrical energy.
Calorie (cal): The amount of energy needed to raise the temperature of 1 gram of water by 1 degree Celsius.
Calorie (Cal, "big calorie"): Equal to 1000 small calories; used in food energy.

Temperature: A measure of the thermal energy of a substance.
Heat: The transfer or exchange of thermal energy between objects due to a temperature difference.

Fahrenheit (°F): Based on salt water; water freezes at 32°F and boils at 212°F.
Celsius (°C): Based on pure water; water freezes at 0°C and boils at 100°C.
Kelvin (K): Absolute temperature scale; zero Kelvin (0 K) is absolute zero, the lowest possible temperature.

Specific Heat Capacity: The quantity of heat required to change the temperature of 1 gram of a substance by 1 degree Celsius.

Formula:

Where q is heat (in joules), m is mass (in grams), c is specific heat capacity, and ΔT is the change in temperature (in °C).

Exothermic: Chemical reactions that release energy to the surroundings (e.g., combustion).
Endothermic: Chemical reactions that absorb energy from the surroundings (e.g., photosynthesis).