Understanding Plastics: Definition, Polymers, and Classification
Understanding Plastics
Today, plastic is used in our daily lives. It has replaced metal parts in the automotive industry and is used in construction, packaging, household appliances (washing machines, blenders, refrigerators, etc.). In the near future, it will be entering other branches of industry, for example, in medicine, such as joint replacement (artificial joints), games of all kinds, and sporting goods. As you can see, the plastic industry is in the process of growth. It is common to see pieces
Read MorePrintmaking Techniques: Etching, Halftone, and Ceramics
Halftone Printing
Halftone printing involves gradually raising the gray and white tones to eliminate roughness, similar to drypoint. It limits the number of prints due to the press crushing the roughness.
Halftone Features
- Amplitude and smoothness of the black.
- A unique engraving system that allows real chiaroscuro.
- Halftone engravings are recognized by a characteristic densely crosslinked derivative of graphing, particularly visible along the edges.
Etching
Etching is an indirect metal plate engraving
Read MoreUnderstanding Chemical Laws: Proust, Dalton, Richter & Radioactivity
Understanding Key Chemical Laws
Law of Definite Proportions (Proust’s Law)
Joseph Louis Proust (1754-1826) argued that the percentage composition of a chemical compound was always the same, regardless of origin. In contrast, Claude Louis Berthollet (1748-1822) stated that elements, within certain limits, could join in all proportions.
Over time, Proust’s criterion was supported by an experiment conducted in 1799, showing that the composition of cupric carbonate was always the same, regardless of its
Read MoreAtomic Models: From Thomson to Quantum Theory
Atomic Models: A Historical Perspective
Thomson’s Atomic Model
Thomson’s atomic model proposed that an atom is a uniform sphere of positive electricity with electrons dispersed throughout, held apart by repulsive forces. This model attempted to explain the neutrality of atoms and the ionization process when electrons are lost.
Rutherford’s Discovery of the Atomic Nucleus
Thomson’s model failed to explain the alpha particle scattering experiments conducted by Geiger and Marsden under Rutherford’s direction.
Read MoreAtomic Properties and Periodic Trends
Atomic Properties
Electron Configuration
The electron configuration of an atom describes the distribution of its electrons among the various atomic orbitals. Several principles govern this distribution:
- Pauli Exclusion Principle: No two electrons in the same atom can have the same four quantum numbers. Each orbital can hold a maximum of two electrons with opposite spins (anti-spin).
- Building-Up Principle (Aufbau Principle): Electrons fill orbitals successively in order of increasing energy.
- Hund’s
Fundamental Chemical Laws and Concepts
The Law of Conservation of Mass
The law of conservation of mass, also known as the law of conservation of matter or the Lomonosov-Lavoisier law, states that in an ordinary chemical reaction, the mass remains constant. That is, the mass of the reactants consumed is equal to the mass of the products obtained.
Dalton’s Law (Law of Multiple Proportions)
Dalton’s law, or the law of multiple proportions, formulated in 1803 by John Dalton, is one of the most fundamental stoichiometric laws. It was demonstrated
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