Chemistry Basics

Acids and Bases

Acids

• Definition: A substance that donates a proton (H+ ion)
• Characteristics:
  • Turn blue litmus paper red
  • Conduct electricity
  • Have a pH less than 7
  • React with metals to produce hydrogen gas
• Examples: HCl (hydrochloric acid), H2SO4 (sulfuric acid), HNO3 (nitric acid)

Bases

• Definition: A substance that accepts a proton (H+ ion)
• Characteristics:
  • Turn red litmus paper blue
  • Conduct electricity
  • Have a pH greater than 7
  • React with oils to produce soap and water
• Examples: NaOH (sodium hydroxide), Ca(OH)2 (calcium hydroxide), KOH (potassium hydroxide)

pH Scale

• pH = -log[H+]
• pH range: 0-14
• Acidic: pH < 7
• Neutral: pH = 7
• Basic: pH > 7

Chemical Reactions

Types of Chemical Reactions

• Combination Reactions: Two or more substances combine to form a new substance
  • Example: 2H2 + O2 → 2H2O
• Decomposition Reactions: A single substance breaks down into two or more substances
  • Example: 2H2O → 2H2 + O2
• Displacement Reactions: One element displaces another element from a compound
  • Example: Zn + CuSO4 → ZnSO4 + Cu
• Oxidation-Reduction Reactions: Involves the transfer of electrons
  • Example: 2Mg + O2 → 2MgO

Chemical Equations

• A representation of a chemical reaction using symbols and formulas
• Reactants: substances on the left side of the equation
• Products: substances on the right side of the equation
• Example: Ca + O2 → 2CaO

Metals and Non-Metals

Metals

• Definition: A substance that is typically hard, shiny, and good conductor of electricity
• Characteristics:
  • Good conductors of electricity
  • Malleable and ductile
  • Have a high density
  • React with acids to produce hydrogen gas
• Examples: Na, Ca, Fe, Cu, Ag

Non-Metals

• Definition: A substance that is typically soft, dull, and poor conductor of electricity
• Characteristics:
  • Poor conductors of electricity
  • Brittle and non-ductile
  • Have a low density
  • Do not react with acids to produce hydrogen gas
• Examples: C, N, O, S, P

Reactivity Series

• A series of metals arranged in order of their reactivity
• Most reactive: K, Na, Ca, Mg
• Least reactive: Ag, Au, Pt