Question

How many Kilojoules are released when 4.00 moles of H2O2 reacts?
2H2O2 --> 2H2O + O2 + 196 KJ
You Answered

Answer 1

The equivalence of this reaction is:

$2 moles \space of \space H_2O_2 \leftrightarrow 2 moles \space of H_2O \leftrightarrow 1 mole \space of \space O_2 \leftrightarrow -196 KJ$

To determine the energy changed thermochemical equation is used:

$4 moles \space of \space H_2O_2 \cdot \frac {-196 KJ}{2 moles \space of \space H_2O_2} = -392 \space KJ$

Answer: the reaction gives off -392 KJ of heat.