Acids, Bases, Salts, and Electrochemistry: A Comprehensive Guide
Acids, Bases, and Salts
Acids
Acids are substances that can donate protons (H+ ions) when dissolved in water. They are characterized by the presence of hydrogen ions in their molecules.
Examples of acids:
- Sulfuric acid (H2SO4)
- Nitric acid (HNO3)
- Hydrochloric acid (HCl)
Bases
Bases are substances that can accept protons (H+ ions) when dissolved in water. They are characterized by the presence of hydroxide ions (OH-) in their molecules.
Examples of bases:
- Sodium hydroxide (NaOH)
- Calcium hydroxide (Ca(OH)2)
- Ammonium hydroxide (NH4OH)
Salts
Salts are ionic compounds formed by the reaction of an acid with a base. They are characterized by the presence of a cation (other than H+) and an anion (other than OH- or O2-).
Examples of salts:
- Ammonium sulfate ((NH4)2SO4)
- Calcium chloride (CaCl2)
- Sodium carbonate (Na2CO3)
Electrochemistry
Weak Electrolytes
Weak electrolytes are substances that partially dissociate into ions when dissolved in water. They allow the passage of a weak electric current.
Strong Electrolytes
Strong electrolytes are substances that completely dissociate into ions when dissolved in water. They allow the passage of a strong electric current.
pH of a Solution
The pH of a solution is a measure of its acidity or basicity. It is defined as the negative logarithm of the hydrogen ion concentration in moles per liter.
pH scale:
- 0 – 7: Acidic
- 7: Neutral
- 7 – 14: Basic
Voltaic Cells
Voltaic cells are electrochemical cells that generate electricity from a spontaneous chemical reaction. They consist of two half-cells connected by a wire.
Electrolytic Cells
Electrolytic cells are electrochemical cells that use electricity to drive a non-spontaneous chemical reaction. They consist of two electrodes immersed in an electrolyte solution.
Electrolysis
Electrolysis is the process of using electricity to drive a chemical reaction. It is used to produce metals, refine ores, and electroplate objects.
Alloys and Metallurgy
Alloys
Alloys are mixtures of two or more metals. They are often stronger and more durable than pure metals.
Metallic Materials
Metallic materials are classified as ferrous (high in iron) or nonferrous (low in iron).
Gathering Process of Metals
The gathering process of metals involves three stages:
- Preliminary treatment: Preparing the ore and separating the desired metal from undesirable materials.
- Metal production: Obtaining the free metal from its combined forms.
- Purification: Removing impurities from the metal.
Corrosion
Corrosion is the process of metal degradation when exposed to the elements. It is characterized by the formation of reddish patches (Fe2O3) that can turn into larger holes.
Magnetism
Magnetism is a phenomenon caused by the motion of electric charges within atoms. It allows certain materials to attract or repel other materials.