Throughout its history, vietnam pursued political independence in the face of foreign domination from many countries. the chinese first controlled the region in 111 bce. their domination lasted until 939 ce, at which point vietnam was able to govern itself independently for nearly 1000 years

Chinese culture, having been established among the elite mandarin class, remained the dominant current among that elite for most of the next 1,000 years (939-1870s) until the loss of independence under French Indochina.

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen

Answerhave flowing water either episodically or during only a portion of the year;