In the course of the nitrogen cycle, are nitrogen atoms themselves ever created? ever destroyed? 6. are nitrogen atoms ever changed into other kinds of atoms? ever changed into other compounds? explain why or why not.

In the nitrogen cycle, the atoms of nitrogen are neither destroyed nor created, or changed into other atoms, this process can be illustrated with the help of the law of conservation of matter that states that matter is neither destroyed nor created in any kind of physical or chemical process.  

Nitrogen fixation is a very essential part of the nitrogen cycle, in the process nitrogen in the atmosphere gets transformed to ammonium ions. The formed ammonia then gets transformed into nitrites, and then into nitrates with the help of certain bacteria by the process of nitrification.  

After that, the process of ammonification takes place in which the amino acids and proteins get dissociated to discharge ammonia, generally in the form of the ammonium ion, which is then transformed into nitrogen in order to continue the cycle.  

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.