Why is only one molecule of n2 needed to produce 2 molecules of nh3?

a. because nitrogen is generated
b. because there are no nitrogen molecules in the atmosphere
c. because nh3 does not always contain nitrogen
d. because each nitrogen molecule contains two nitrogen atoms

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante

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.