Percent Composition By Mass

Both of these involve reactions with hydrochloric acid and both involve interpretations from a graph, where kinetics is also tested. Question 5 looks at the reaction between CaCO3 and HCl and then determines the identity of M in M(OH)2. Question 6 looks at the reaction between Mg and HCl. Note that 9min30s into the snapkast I wrote the formula CaCl2 where I should have written CaCO3.

This Chemistry lesson is titled Percent Composition Common Mistakes and will give a detailed explanation of the topic.

This Chemistry lesson is titled Whats the Difference between Mass Number and Atomic Mass and will give a detailed explanation of the topic.

This Chemistry lesson is titled How to Calculate Atomic Mass Practice Problems and will give a detailed explanation of the topic.

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.