6. Think of some other chemical reactions. List them and the type of reaction: exothermic or endothermic. Example: Burning coal - exothermic

Explanation:

When Sulphuric acid is slowly poured into water in a beaker the beaker becomes hot and this is exothermic reaction

when ammonium chloride is dissolved in water in a beaker the beaker becomes cold and this is endothermic reaction

personal, she chose to do it.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.