-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 = 
= 
=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:
= 
x = 
= -20.16 KJ
Thus, - 20.16 KJ of energy will be released.
Answer:
n = 12.18 moles
Explanation:
Given that,
The volume of a canister, V = 1 L
The temperature of the canister, T = 100 K
Pressure, P = 100 atm
We need to find the number of moles of gas. Let there are n number of moles. We know that,
PV = nRT
Where
R is gas constant, R = 0.0821 L*atm/mol*K

Hence, there are 12.18 moles of gas.