A decomposition reaction is a type of chemical reaction where a single compound is broken down into two or more elements or new compounds.
<em><u>Decomposition reactions involve a single substance as a reactant and more than one substance as the product.</u></em> Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.
In the question above; <em><u>the reaction; 2SO3 (g) → 2SO2 (g) + O2 (g) is an example of decomposition reaction.</u></em>
Because the object that has more weight has a greater momentum and the lightest object that has a less momentum will be easier to change because its lighter.