Atomic Structure: From Dalton to the Quantum Model
Dalton’s Atomic Theory
In the nineteenth century, English chemist John Dalton, drawing on the ideas of Leucippus and Democritus, set out the atomic theory which states that:
- Chemical elements are composed of tiny indivisible particles called atoms.
- Atoms of the same element are equal in mass and other properties.
- Atoms of different elements differ in mass and other properties.
- Atoms of different elements combine to form compounds.
Discovery of the Electron
Michael Faraday applied electric shocks to containers
Read MoreGas Properties: Specific Volume, Viscosity, and Compressibility
Specific Volume (v) is the volume occupied by a unit mass of material. It is the inverse of density and does not depend on the amount of matter. For example, two pieces of iron with different sizes have different weights and volumes, but their specific gravities are equal. This is independent of the material amount. Examples of intensive properties include boiling point, brightness, color, hardness, and melting point.
Where: V is volume, m is mass, and ρ is the density of the material.
It is expressed
Steel Production: An Overview of Furnace Processes and Alloying Elements
Steel Production Processes
Open Hearth Furnace
One of the most popular steel production methods, the open hearth furnace, can hold 10 to 540 tons of metal. Its shallow depth allows flames to directly heat the load. Fuel sources include gas, tar, or oil. These regenerative furnaces often have side fireplaces to expel heated gases used for air and fuel heating. Open hearth furnaces typically have basic linings, but acid linings (silica and clay brick walls) also exist. Basic linings offer better control
Read MoreNuclear Stability and Reactions: A Comprehensive Overview
Nuclear Stability and Reactions
From Two Viewpoints: Nuclear Power and Energy
A. Strong Nuclear Force
The strong nuclear force, theorized by Hideki Yukawa, is the strongest of the fundamental forces but has the shortest range. It is independent of charge and works only for particles within a distance of less than 10-16 meters. For distances between 10-16 and 10-14 meters, there is less repulsion. Nuclei with approximately equal numbers of protons (Z) and neutrons (N) are stable. As Z increases, the
Read MoreStoichiometry and Natural Gas: LNG, LPG, and NGV
Stoichiometry
In chemistry, stoichiometry is the calculation of the quantitative relationships between reactants and products during a chemical reaction. These relationships can be deduced from the atomic theory, although historically spelled out without reference to the composition of matter, according to different laws and principles.
The first to set out the principles of stoichiometry was Jeremias Benjamin Richter (1762-1807) in 1792. He wrote:
Stoichiometry is the science that measures the quantitative
Read MoreEarth’s Seasons & Climate Zones: An In-depth Guide
Module 3: Seasons
Earth’s Axis and Movement
1. What is the Earth’s axis?
It is an imaginary straight line passing through the Earth’s center. The Earth rotates around this line. The points where this line intersects the Earth’s surface are the North and South Poles.
2. What are the movements of Earth’s axis called?
- Precession
- Nutation
3. What is the Equator?
It is the great circle perpendicular to the Earth’s axis that divides the Earth into two hemispheres: the Northern Hemisphere (or Boreal) and the Southern