Queries Answer for lesson 1

Group 1's queries

1) From the video, decomposition and combustion both produce carbon dioxide. Why is both reaction classified differently?

Ans: Combustion must involve the reaction of oxygen with the reactant while decomposition do not.

2) From our past knowledge, for combustion, heat is given out. But why is it still consider as combustion when no heat is given out?

Ans: Combustion can be classified as endothermic (heat absorbed) and exothermic (heat releaased). As long as oxygen is taken in, no matter heat is taken in or given out, the reaction is considered as combustion.

Group 4's queries

3) What is the key difference between combustion and double replacement reaction?

Ans: Both reaction involved the combination of two molecule and separation of two molecule after the reaction. However oxygen is required to be the reactant for combustion whereas double replacement reaction can be any two molecules.

Group 5's queries

2) How can we differentiate between complete combustion and incomplete combustion?

Ans: Both reaction require oxygen to be taken in during the process. However, carbon dioxide (CO2) is produced for complete combustion where as carbon monoxide (CO) and soot (C) is given out for incomplete combustion.