Question

A chemist measures the energy change Delta H during the following reaction: 2H_2I(l) rightarrow 2H_2(g) + O_2(g) Delta H = 572. kJ Use the information to answer the following questions. This reaction is ... exothermic endothermic Suppose 94.8 g of H_2O react. Will any heat be released or absorbed? Yes, absorbed Yes, released No If you said heat will be released or absorbed in the second part of this question, calculate how much heat will be released or absorbed. Round your answer to 3 significant digits. kJ

Answer 1

a)
since ΔH is positive, heat is absorbed
It is endothermic reaction

b)
yes, absorbed

c)
number of moles of H2O = mass/molar mass
= 94.8 / 18
= 5.27 mol

heat absorbed when 2 mol of H2O reacts = 572 KJ
for 5.27 mol, heat absorbed = (572*5.27)/2 = 1506 KJ
Answer: 1.51*10^3 KJ