Thermochemical Equations Practice Problems

UN Livestock Long Shadow Chapter 1 - CO2

We'll go step by step through how to balance an oxidation reduction (redox) reaction in acidic solution. Most importantly, both charges and atoms must balance. Here are the steps: first, calculate oxidations numbers for all the elements in the equation. Next, figure out what is being oxidized and what is being reduced. Then, write half reactions for the oxidation and reduction. After that, balance each half reaction: first, for the atoms other than O and H, then for O and H, and finally for charge by adding electrons. After being balanced, the oxidation and reduction half reactions are ready to be added back to together. Make sure that the number of electrons is the same in the oxidation and reduction half reactions. If they are not, multiply one or both of the half reactions to make the number of electrons the same. Then, combine the oxidation and reduction half reaction, canceling out stuff that appears on both sides of the equation. Lastly, do a final check to make sure that everything balances: both atoms and charge.

In this video lesson, Mr. Scullion demonstrates a reacting mass problem involving the thermite displacement reaction. Try the problem out on your own prior to finding out the solution.

Mass Balance Equations (MBE) states that the quantity of all species in a solution containing a particular atom must be equal to the amount of that atom delivered to the solution. Dissociation of diprotic acid, H2S, in H2O occurs in a stepwise manner. In this video, acid dissociation beginning with H2S dissociating to HS- and then to S2- will be animated. In addition, subsequent base back dissociations are also shown. MBEs are written for the dissociation of H2S in H2O. Videos are also available at: http://www.chemistry.nus.edu.sg/education/undergrads/CourseResources/course_resources.htm = Video Gallery or the "Animol" app on Apple and Google Play Store.

This Chemistry lesson is titled Introduction to Thermochemistry and Enthaply and will give a detailed explanation of the topic.