C I hope I help good luck
I think the answer is reversible. Reversible reaction is a kind of reaction which can react in both direction at the same time. And when the both side reactions get the same speed, the reaction is at a equilibrium state.
½H2(g) + ½I2(g) → HI(g) ΔH = +6.2 kcal/mol
or...
½H2(g) + ½I2(g) + 6,2kcal/mole → HI(g)
________
21.0 kcal/mole + C(s) + 2S(s) → CS2(l)
or...
C(s) + 2S(s) → CS2(l) ΔH = +2,1 kcal/mole
_________
ΔH > 0 ----------->>> ENDOTHERMIC REACTIONS
Answer:
The answer is Ionization energy.
Explanation:
Ionization Energy. The ionization energy tends to increase as one moves from left to right across a given period or up a group in the periodic table.