When is a rock considered an ore choose all that apply?

A rock would be considered as an ore if it contains mineral that has elements that are important like metals. Also, these minerals should be present in sufficient amount or present in high concentration. These rocks are usually obtained by mining. 

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

Answer. first blank ; ; ; clockwise; the second blank; ///clockwise;