Understanding Atoms, Molecules, and Cells: A Primer
Atom: The Basic Unit
An atom is the smallest unit of a chemical element that retains its identity and properties and cannot be divided by chemical processes.
Atomic Structure
- Proton: A subatomic particle with a positive (+) charge.
- Neutron: An uncharged subatomic particle.
- Electron: A subatomic particle with a negative (-) charge.
Chemical Elements and Bonds
A chemical element is a substance that cannot be decomposed by chemical reactions. Substances are formed by molecules of a single type, such as O,
Read MoreUnderstanding Electrostatics: Principles and Applications
Electrostatics
Early Observations
Thales observed that rubbing amber with cat fur attracted feathers. Gilbert manufactured the versorium.
Types of Electricity
Charles du Fay discovered that rubbing glass with silk electrified objects, and similar objects repelled each other. He deduced two types of electricity: resinous and vitreous.
In 1747, Franklin named the charge gained by rubbed bodies as positive and the charge lost as negative. Bodies with the same charge repel, while those with different charges
Read MoreCopper Extraction: A Comprehensive Process Analysis
Copper Extraction Process
Copper is mainly extracted from its sulphide ores. The different steps involved in the extraction of copper from copper pyrites ore (CuFeS2) are:
1) Crushing and Pulverization
The sulphide ore is crushed in a big jaw crusher and pulverized in a ball mill.
2) Concentration
The powdered ore is concentrated by the froth flotation process. In this process, the powdered ore is mixed with water containing a little pine oil in a big tank and agitated by blowing air. The sulphide ore
Read MoreIons, Bonds, and Macromolecules: Chemistry Essentials
(a) Ions and Ionic Bonds
Ion: An ion is a charged atom (i.e., the number of protons does not equal the number of electrons). Ions form by losing an electron (oxidation), which increases the charge by 1, or by gaining one (reduction), which decreases the charge by 1. Remember OIL RIG: oxidation is loss, reduction is gain. A positively charged atom is called a cation, and it is usually a metal. A negatively charged atom is called an anion, and it is a non-metal.
Ionic bond: An ionic bond is the bond
Read MoreRadioactive Decay: Alpha, Beta, Electron Capture
Alpha Decay
Radioactive nuclides with a very large atomic number (> 82) often decay with the emission of an alpha particle. By increasing the number of protons, Coulomb repulsion forces exceed the nuclear forces. Thus, the unstable nucleus emits a particle composed of two protons and two neutrons. The atomic number (Z = number of protons) decreases by two, and the mass number decreases by four. Q is the energy released in the process, the decay energy. Q is equivalent to the difference in mass
Read MoreUnderstanding Laws, States of Matter, and Chemical Reactions
A law is a brief statement of a general nature about regularities in nature observed experimentally. Boyle’s Law states that for a mass of gas at constant temperature, the product of the gas pressure exerted by the volume it occupies is constant.
States of Matter
- Gaseous State: It has no fixed shape or volume, is compressible, and flows easily.
- Liquid State: It adapts to the container, is difficult to compress, and flows.
- Solid State: It has its own rigid shape and volume and is hardly compressible.