In my Physical Science class, we are learning about chemical formulas and how to balance them. I balanced this equation:

$$ \ce{Fe2O3 + Al -> Fe + Al2O3} $$

One of the other students asked me if this chemical formula releases or absorbs heat.

Could anyone help me give a great explanation for this question?

  • $\begingroup$ en.wikipedia.org/wiki/Aluminothermic_reaction $\endgroup$
    – Mithoron
    Apr 27 '15 at 21:27
  • $\begingroup$ Check $\Delta H$ tables and calculate if the reaction is endothermic or exothermic. $\endgroup$
    – Asker123
    Apr 27 '15 at 21:38
  • 5
    $\begingroup$ @Sydney U: Please note currently (22:10 UTC time), your reaction equation is not yet balanced correctly. $\endgroup$
    – Buttonwood
    Apr 27 '15 at 22:12
  • $\begingroup$ Look up thermite for more information on this displacement reaction. My students enjoyed seeing it demonstrated. $\endgroup$ Apr 28 '15 at 0:31

The best way to solve this problem is to look at the $\Delta H$ charts found online. Using the simple equation below will give you the answer.

$$\sum \Delta H_{\text{Products}} - \sum \Delta H_\text{Reactants} = \Delta H_{\text{Reaction}}$$ If the $\Delta H$ is positive in sign then the reaction is endothermic and if it is negative in sign then it is exothermic.


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