Crossword-Solution: ENDOTHERMIC 11 letters, 4 clues 🏆 scrabble score: 19

Compounds are therefore of two kinds: those which absorb heat during their preparation, and consequently liberate heat when they are decomposed--such being termed endothermic; and those which evolve heat during their preparation, and consequently absorb heat when they are decomposed--such being called exothermic.

Seeing that there is a tendency in nature for the steady dissipation of energy, it follows that an exothermic substance is stable, for it tends to remain as it is unless heat is supplied to it, or work is done upon it; whereas, according to its degree of endothermicity, an endothermic substance is more or less unstable, for it is always ready to emit heat, or to do work, as soon as an opportunity is given to it to decompose.

The theoretical and practical results of this circumstance will be elaborated in Chapter VI., when the endothermic nature of acetylene is more fully discussed.

The reaction between carbide and slaked lime, however, is endothermic, absorbing 1.1 calories; and therefore it requires external assistance (presence of an elevated temperature) to start it, or continuous introduction of heat (as from the reaction between the rest of the carbide present and the water) to cause it to proceed.

Acetylene is an "endothermic" compound, as has been mentioned in Chapter II., where the meaning of the expression endothermic is explained.