Episode 19 – Conversatin’ About Conservation


First, you will need to download the Coversatin’ About Conservation lab manual.


The Law of Conservation of Mass states that in a chemical reaction, matter is neither created nor destroyed. Think about a rock, for example. If you were to break a rock with a hammer, the rock would likely shatter if you were able to hit it hard enough. If you gathered every piece of that shattered rock, the pieces would weigh the same as the original rock itself before it was smashed. Smashing a rock in this way, however, you risk loosing some pieces (or having a rock hit a window!). This would not give an accurate measurement in mass. How could you capture the mass of this rock precisely before AND after it is hit with a hammer?

The answer is in what system you are using. A system is a place where reactions take place. An open system would be the situation we described above; smashing a rock in an open space. A closed system, you guessed it, is a closed space. If we repeat the experiment above but place the rock in a closed plastic bag, we would not lose any pieces! This gives us a precise mass before and after the reaction has occured.

This activity will discuss how we can use systems to our advantage when completing reactions to either release or harness the mass of elements used in a reaction.

Saskatchewan Curriculum Connections: CH30-EQ1: Consider, qualitatively and quantitatively, the characteristics and applications of equilibrium systems in chemical reactions. (SI, DM, TPS) SCI10-CR3:Represent chemical reactions and conservation of mass symbolically using models, word and skeleton equations and balanced chemical equations.