How is dinitrogen (1) oxide distinguished shed from oxygen​

To distinguish between nitrous oxide and oxygen. Ignite the candle and lower it to the bottom of the test tube into the N2O(g). It will burn much longer than in air and will burn with an enlarged flame. Repeat the candle experiment with O2(g) you will observe dazzling combustion of a candle in the presence of oxygen.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.