Identify whether the following processes are endothermic or exothermic.

  1. Thermal decomposition of limestone to form calcium oxide (CaO) and carbon dioxide
  2. Explosion of a firecracker triggered by a spark
  3. Combustion of hydrogen gas
  4. Dissolving an acid in water
  5. Baking bread
  6. Heating causes sodium bicarbonate (NaHCO3) to decompose