Decomposition

Question 1

Generalised definition of decompostition

Answer 1

When a single reactant breaks down into multiple substances/products

Thermal → decomposition initiated by the addition of energy (heat)

Electricity → decomposition initiated by the addition of electrolytic

Catalyst → decomposition initiated by the presence of a catalyst

Question 2

How is mass preserved in decomposition?

Answer 2

The reactants will weigh the same as the products unless a reactant or product has been introduced or lost from the system. There are only - - - - - - atoms present on both sides of the equation, but these atoms have been rearranged into new combinations. The reactants and products both have the same total number of each type of atom.

(The decrease in mass can be caused because carbon dioxide gas has escaped from the system.)

Question 3

How does sodium bicarbonate (baking soda) affect convervation of mass?

Answer 3

Baking soda is used in baking because the heat decomposes it to produce CO2 gas which gets trapped inside the batter to make it rise. the CO2 gas and some water vapor escapes the batter making it seem like mass hasn’t been conserved because the CO2 and H2O is no longer present when measured.