Question

Consider the following reactions. (Note: (s) = solid, (l) = liquid, and (g) = gas.) ½H2(g) + ½I2(g) → HI(g), ΔH = +6.2 kcal/mole 21.0 kcal/mole + C(s) + 2S(s) → CS2(l) What type of reaction is represented by the previous two examples?

Answer 1

Answer:

Endothermic reaction.

Explanation:

Endothermic reaction is which requires or absorb energy

Exothermic reaction is which release energy.

In endothermic reaction the energy of products is more than the energy of reactants so the enthalpy of reaction is positive.

½H2(g) + ½I2(g) → HI(g), ΔH = +6.2

Thus the above reaction is endothermic

As energy is absorbed in endothermic reaction so we write the energy on reactant side.

hence the second reaction is also endothermic reaction.

Answer 2

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