The slideshow describes an exothermic reaction between dilute sodium hydroxide and hydrochloric acid, and an endothermic reaction between sodium carbonate and ethanoic acid.

The sodium reacts with the water and gets very hot, producing sodium hydroxide and hydrogen gas ... The calcium reacts most vigorously with the hydrochloric acid, producing bubbles. The reaction ...

Sodium hydroxide is added to a cylinder of aluminum nitrate, precipitating out aluminum hydroxide. When additional base is added, the precipitate dissolves. The reactions can then be reversed with the ...