Question

Instructions
Answer the following questions:
(1) Give two examples which illustrates the evolution of a gas, the change in colour of
reactants and the formation of precipitate during a chemical reaction.
(2) Define exothermic and endothermic reactions Support your answers with two examples for
each.
Submit today by 6 pm​

Answer 1

1. carbonic acid breaks down to water and carbon dioxide, sulfurous acid breaks down to water and sulfur dioxide, and ammonium hydroxide breaks down to water and ammonia gas.

2.Endothermic Reaction Definition. An endothermic reaction is any chemical reaction that absorbs heat from its environment. The absorbed energy provides the activation energy for the reaction to occur. A hallmark of this type of reaction is that it feels cold .These examples could be written as chemical reactions, but are more generally considered to be endothermic or heat-absorbing processes:

• Melting ice cubes.
• Melting solid salts.
• Evaporating liquid water.
• Converting frost to water vapor (melting, boiling, and evaporation, in general, are endothermic processes.

An exothermic reaction is a chemical reaction that releases energy through light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation: reactants → products + energy. Exothermic Reaction means "exo" meaning releases and "thermic" means heat. Examples of Exothermic Reactions

• any combustion reaction.
• a neutralization reaction.
• rusting of iron (rust steel wool with vinegar)
• the thermite reaction.
• reaction between water and calcium chloride.
• reaction between sodium sulfite and bleach (dilute sodium hypochlorite)
• reaction between potassium permanganate and glycerol.