Chemical Elements and the Periodic Table: Properties and Structure
Metals and Non-Metals
Since antiquity, items such as gold, silver, etc. have been discovered over time. Up to now, more than 100 have been identified. A first classification of items, focusing on appearance and physical properties, allows for 2 groups: metals and non-metals.
Metals and Non-Metals
To distinguish one from the other, we will name characteristics that make them different:
Metallic Elements
- Have a characteristic brightness.
- Are opaque and good conductors of heat and electricity.
- Are usually
Thermodynamics Problems and Solutions: Ideal Gas Law
Ideal Gas Law and Thermodynamics Problems
Problem 1
An ideal gas occupies a volume of 100 cm3 at 20°C and a pressure of 100 Pa. Determine the number of moles of gas in the vessel.
1 Pa * 1 m3 = 1 Joule
PV = nRT
100 Pa * 10 * 10-7m3 = n
8.31 * 293
n = 4.11 * 10-6
Problem 2
Calculate the volume occupied by one mole of gas under normal conditions.
PV = nRT
1 atm * V = 1 mol * 0.082 * 273
V = 22.4 L
Problem 3
Helium is introduced into a mobile container. The initial pressure, volume, and temperature of the gas are
Read MoreAcid-Base Titration and Salt Hydrolysis in Chemistry
Acid-Base Titration
In both industrial processes and in the laboratory, it is very common to determine the amount of acid or base in a sample. Titration, specifically acid-base titration, is a method of chemical analysis used to determine the unknown concentration of an acidic or basic solution. This is achieved by using a standard solution, which is a basic or acidic solution of known concentration.
The experimental procedure involves placing a known volume of the solution to be analyzed in a conical
Read MoreChemical Properties and Reactions: Elements, Compounds, and Laws
Periodic Properties of Elements
Atomic Radius
The atomic radius is the distance from the center of the nucleus to the area corresponding to the outermost level. Over a period, the radius decreases from left to right.
Ionization Energy
Ionization energy is the energy required to form an ion (cation); the energy that must be delivered to an isolated atom to remove an electron. The ionization increases from left to right, and in a group, it decreases from top to bottom.
Electronegativity
Electronegativity
Read MoreChemical Bonding: Types, Properties, and Structures
Unit 2: Chemical Bonding
Ionic Bond – Lattice Energy
Where K is Coulomb’s constant, Z represents the charges of the ions, e is the absolute value of the electron charge, N is Avogadro’s number, d is the internuclear distance, m is the Madelung constant, and ε is the Born exponent.
Born-Haber Cycle and Lattice Energy
The Born-Haber cycle is a thermodynamic cycle that analyzes all the processes involved in the formation of one mole of an ionic compound from its constituent elements in their most stable
Read MoreUnderstanding Matter and Energy: Properties, Laws, and Atomic Structure
**Physical Property**
All properties of matter are subject to the scientific method: observation, hypothesis formulation, experimentation, communication of results, and extraction of conclusions.
**Physics**
Studies the changes in materials in which the substances are not transformed into other new substances.
**Chemistry**
Studies the transformations that substances can experience: structure, composition, and properties.
**Absolute Error**
The difference in absolute value between the approximate value
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