-20.16 KJ of heat are released by the reaction of 25.0 g of Na2O2.
Explanation:
Given:
mass of Na2O2 = 25 grams
atomic mass of Na2O2 = 78 gram/mole
number of mole = [tex]\frac{mass}{atomic mass of 1 mole}[/tex]
= [tex]\frac{25}{78}[/tex]
=0. 32 moles
The balanced equation for the reaction:
2 Na2O2(s) + 2 H2O(l) → 4 NaOH(aq) + O2(g) ∆Hο = −126 kJ
It can be seen that 126 KJ of energy is released when 2 moles of Na2O2 undergoes reaction.
similarly 0.3 moles of Na2O2 on reaction would give:
[tex]\frac{126}{2}[/tex] = [tex]\frac{x}{0.32}[/tex]
x = [tex]\frac{126 x 0.32}{2}[/tex]
= -20.16 KJ
Thus, - 20.16 KJ of energy will be released.
