Understanding Matter: Properties, Changes, and Laws
Physical Property
A characteristic of matter that can be observed or measured without changing the sample’s composition; also describes a pure substance having a uniform and unchanging composition.
Extensive Property
Physical properties that are dependent on the amount of a substance present, such as length, shape, weight, and volume.
Intensive Properties
Physical properties of matter that are independent of the amount of a substance, such as density, color, and specific heat.
Chemical Properties
The ability
Understanding the Periodic Table of Elements
ITEM 8 – Periodic Table
- Pure Substance: A substance that consists of a single component, has characteristic properties and a fixed, unchanging chemical composition. It cannot be separated into other components by physical methods.
- Mixture: A combination of two or more substances in a way that does *not* produce a chemical reaction. The individual components maintain their identity and chemical properties.
- Chemical Element: Pure substances that cannot be decomposed into any other simpler pure substance
Energy Storage: Types, Reactions, and Battery Materials
Main Types of Energy Storage
- Electrochemical: Fuel Cell
- Electrical: Capacitor
- Mechanical: Flywheel
- Thermal: Molten Salt
- Chemical: Hydrogen
- Biological: Starch
Gibbs Free Energy
G = Gproducts – Greactants
Voltage: E = -ΔGr / zF
Temperature Dependence: G = H – TΔS
Main Reactions in Batteries
- Reconstitution (Major Change)
- Formation Reaction
- Displacement
- Insertion (Small Change): xA + BC = AxBC
Important Practical Parameters in Batteries
- Specific Energy
- Energy Density
- Operating Voltage
- Energy Quality
- Charge Capacity
Liquid
Read MoreCarbohydrates: Structure, Types, and Functions
Carbohydrates: Biomolecules are formed by C, H, and O in a ratio that indicates its empirical formula CnH2nOn, although exceptionally they may contain atoms of H, S, and P. These compounds may represent up to 90% of the biomolecules organic in the body, hence its importance. Also known as carbohydrates because they were initially thought to be formed by the structure of carbonated and hydrated water molecules. Chemically, the carbohydrates are aldoses or ketones with multiple hydroxyl groups, although
Read MoreAtomic Structure, Radioactive Decay, and Chemical Bonds Explained
Atomic Nucleus and the Strong Force
Protons and neutrons bind together to form the nucleus of an atom. Negatively charged electrons are attracted to the positively charged protons and orbit the nucleus. The strong force, also known as the strong interaction, color force, or strong nuclear force, holds protons and neutrons together. This force is more powerful than the electrical repulsion between protons, but it requires the particles to be in close proximity.
Ions: Atoms with a Charge
An ion is an
Read MoreWater and Mineral Salts in Living Organisms
Water: The Essence of Life
Properties of Water
Water, the most abundant molecule in living matter, comprises 20% to 85% of an organism’s mass, decreasing with age. A water molecule consists of two hydrogen atoms and one oxygen atom, covalently bonded at a 104.5° angle. Although electrically neutral, the atoms have different electronegativity values, giving water its polar character. This polarity allows water molecules to form hydrogen bonds with each other.
- Dielectric Constant: The force with which