Chemistry Basics

Acids and Bases

Acids:

• Definition: Substances that donate a proton (H+ ion) in a solution
• Characteristics:
  • Turn blue litmus paper red
  • Conduct electricity
  • Have a pH below 7
• Examples: Hydrochloric acid (HCl), Sulphuric acid (H2SO4), Nitric acid (HNO3)

Bases:

• Definition: Substances that accept a proton (H+ ion) in a solution
• Characteristics:
  • Turn red litmus paper blue
  • Conduct electricity
  • Have a pH above 7
• Examples: Sodium hydroxide (NaOH), Calcium hydroxide (Ca(OH)2), Ammonia (NH3)

pH Scale:

• Range: 0-14
• pH 7: Neutral (neither acidic nor basic)
• pH < 7: Acidic
• pH > 7: Basic

Chemical Reactions

Types of Chemical Reactions:

• Combination Reaction: Two or more substances combine to form a new substance
• Decomposition Reaction: A single substance breaks down into two or more substances
• Displacement Reaction: One element displaces another element from a compound
• Oxidation-Reduction Reaction: Loss of electrons (oxidation) and gain of electrons (reduction) occur simultaneously

Chemical Equation:

• A representation of a chemical reaction using chemical formulas and symbols
• Reactants: Substances on the left side of the equation
• Products: Substances on the right side of the equation
• Arrow: Indicates the direction of the reaction

Metals and Non-Metals

Metals:

• Definition: Substances that are typically shiny, malleable, and good conductors of electricity
• Characteristics:
  • High density
  • High melting and boiling points
  • Good conductors of electricity
• Examples: Copper (Cu), Iron (Fe), Aluminum (Al)

Non-Metals:

• Definition: Substances that are typically dull, brittle, and poor conductors of electricity
• Characteristics:
  • Low density
  • Low melting and boiling points
  • Poor conductors of electricity
• Examples: Carbon (C), Nitrogen (N), Oxygen (O)

Metalloids:

• Definition: Substances that exhibit some properties of metals and some properties of non-metals
• Examples: Silicon (Si), Germanium (Ge), Arsenic (As)

Note: These notes are concise and focus on key facts and concepts, aiming to provide a clear and brief overview of the topics.