Chemistry Fundamentals: Substances, Mixtures, and Properties
What is a Mixture?
It is the union of two or more substances in different proportions.
What is a Pure Substance?
These are formed by identical particles, such as water, alcohol, and oxygen.
Types of Mixtures
Homogeneous Mixtures
They are those whose components are indistinguishable to the naked eye and look the same throughout the mixture.
Heterogeneous Mixtures
These are mixtures whose components are distinguishable to the naked eye.
Differences of Colloid Solutions
A colloid solution is observed using an
Read MoreUnderstanding Chemical Systems and Their Phases
System is the set of chemicals selected for study in isolation from the outside environment. It is a mixture of simple and composite bodies in varying proportions, among which can produce physical, chemical, or physical-chemical phases. Any part of a system that has properties physically distinguishable from other single components or composite bodies that make up the system initially can be distinguished in the system in equilibrium. Solid solutions: their classes. Plot your cooling solid solution
Read MoreAtomic Structure, Electron Configuration, and Chemical Properties
Bohr’s Atomic Model
Bohr’s model for the hydrogen atom aimed to explain its electronic structure and justify its atomic spectrum. It was based on three main postulates:
- The electron revolves around the nucleus in specific circular orbits of fixed energy.
- Only orbits where electrons possess specific, quantized energy values are allowed. These orbits are called energy levels.
- When an electron transitions from a higher energy level to a lower one, the energy difference is emitted as light (a photon).
Electron
Read MorePeriodic Table: Element Classification, Trends, and Group Properties
Periodic Table Structure and Properties
The Periodic Table is a method of classifying elements. They are arranged in order of increasing atomic number. The columns are called groups. The rows are called periods. Metals are generally found to the left and non-metals to the right. Elements in the same group typically have similar chemical properties. For a specific main group, the group number indicates the number of valence electrons, and the period number indicates the number of electron shells occupied
Read MoreEssential Dental Materials: Properties and Clinical Uses
Dental Materials for Tooth Reconstruction
Materials for rebuilding teeth must be durable (not prone to breaking quickly), resistant to mastication, and aesthetically pleasing, resembling natural teeth.
Pulp Protection and Fillings
Pulp Protective Materials:
- Fluid composites
- Glass ionomer cements
- Calcium hydroxide liners
Types of Fillings:
- Composite Fillings: Made from resin-based materials.
- Amalgam Fillings: Historically used, containing mercury and silver. Often supplied in pre-dosed capsules for mixing.
Types of Chemical Bonds Explained
In chemistry, atoms are held together by chemical bonds. The type of bond formed dictates many of the substance’s properties. Three primary types of chemical bonds are covalent, metallic, and ionic.
Covalent Bonds
In a covalent bond, two bonded atoms share electrons. When the atoms joined by a covalent bond are the same (e.g., N₂, O₂), neither atom attracts the shared electrons more strongly than the other. This is called a nonpolar covalent bond or simply nonpolar.
If the atoms of the covalent
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