What is the mass percentage of C in C₂H₄O₂? Provide an answer to two decimal places.

40.002

Explanation:

The percent composition of carbon in acetic acid is 40.002%

the answer is na (sodium)

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.