If a reaction mixture contains only n 2o and no2 at partial pressures of 1.0 atm each the reaction will be spontaneous until some no forms in the mixture. what maximum partial pressure of no builds up before the reaction ceases to be spontaneous

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.