Commutator (electric) A commutator is a moving part of a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine.
The word equation that would represent the formation of lithium oxide from lithium metal and oxygen is: lithium + oxygen to lithium oxide. In chemical symbols, the balanced chemical equation is expressed as: Li + O2 = Li2O.
In Trial 1, the empirical formula of magnesium oxide = Mg2O3. In Trial 2, the empirical formula of magnesium oxide = MgO. A strip of magnesium metal reacts with oxygen in the air to produce magnesium oxide. In order to experimentally determine the percentage composition and empirical formula of magnesium oxide, a piece of magnesium is heated strongly to react with the oxygen in the air.