The decomposition of #H_2O_2# produces water and oxygen gas, releasing 197 kJ per one mole of #H_2O_2#. How much energy is released if we start with 798 grams of #H_2O_2#?

1 Answer
Dr. Hayek
May 24, 2016

#q=4629.5kJ#

Explanation:

The amount of heat (#q#) released from decomposing #798g# of #H_2O_2# could be found by:

#q=DeltaHxxn# where, #DeltaH# is the enthalpy of the reaction and #n# is the number of mole of #H_2O_2#.

Note that #DeltaH=197kJ*mol^(-1)#

To find #n#, we can simply use: #n=m/(MM)# where, #m=798g# is the given mass and #MM=34g*mol^(-1)# is the molar mass of #H_2O_2#.

#n=m/(MM)=(798cancel(g))/(34cancel(g)*mol^(-1))=23.5molH_2O_2#

Thus, #q=DeltaHxxn=197(kJ)/(cancel(mol))xx23.5cancel(mol)=4629.5kJ#

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