GenChem (Lab)

• Indications of a chemical reaction

  • Change of color
  • Formation of precipitate
  • Evolution of gas
  • Evolution of heat
• Hydrogen gas is colorless
• Flame color tests for metal elements

  • Potassium (K): lavender/purple
  • Sodium (Na): yellow
  • Lithium chloride: carmine
  • Strontium chloride: red
  • Calcium chloride: orange
  • Borax: yellow-green
• Types of chemical changes

  • Synthesis
  • Decomposition
  • Single displacement
  • Double displacement
• Reaction of concentrated nitric acid and copper


  HNO3 + Cu → Cu(NO3)2 + NO + H2O
• Reaction of dilute nitric acid and copper

  HNO3 + Cu → Cu(NO3)2 + NO + H2O
• Copper (II) nitrate


  Blue solution
• Nitrogen dioxide


  Brown gas
• Copper (II) hydroxide


  Blue precipitate
• Copper (II) oxide


  Black solid
• Copper (II) sulfate


  Blue solution
• Copper (II) sulfate


  White/grayish solid
• Zinc chloride


  White crystalline solid
• Hydrogen gas bubble formation

  Powdery white
• Calcium hydroxide


  Jelly-like white
• Magnesium hydroxide


  Yellow/brown precipitate
• Iron (II) hydroxide


  Hydrogen gas formed
• When acid is added to metal

  Hydrogen gas is formed
• When a base is added to a metal


  Metal hydroxide is formed
• A synthesis or combination reaction involves the combination of two or more reactants to form a single product
• An analysis or decomposition reaction involves the breakdown of a single reactant into two or more products
• A substitution or single displacement reaction involves the replacement of one element in a compound by another element
• A metathesis or double displacement reaction involves the exchange of ions between two compounds to form two new compounds
• In a metathesis reaction, a blue precipitate of copper (II) hydroxide forms, and the solution is colorless
• In a metathesis reaction, the products are potassium chromate and sodium sulfate
• In a substitution reaction, hydrogen gas is generated, and heat is released
• In a substitution reaction, the color of the solution changes from blue to green, producing ferrous sulfate as the product
• In a substitution reaction, the color of the solution changes from colorless to pale yellow, and a yellow precipitate of lead chromate forms
• In a substitution reaction, the solution turns bright red