Which of the following is represented in the highest percentage by volume in dry air? a. oxygen b. hydrogen c. carbon dioxide d. nitrogen

a chemical reaction happens

explanation:

answer; /// the amount of material dissolved in a measure of liquid(concentration) the above statement is (true); /// good luck

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.