Electrolysis of Water

Electrolysis of Water

OBJECTIVES

1. What is the balanced chemical equation of this experiment?

2. Is there qualitative evidence to support the balanced reaction?

3.Could you collect quantitative data to 'prove' the balanced equation?

4. Can you draw the particle diagram?

So this experiment basically separated the components of water into hydrogen and oxygen gases. The procedure first included filling two tubes with a baking soda solution and lining the tubes up with the tacks in the bottom of a small plastic cup. Next was seemingly most challenging part of this lab... flipping the cup with the tubes in it upside down and quickly (very quickly) filling the cup with tap water before any gas bubbles could escape. This ensured all the gas was trapped. Lastly, the bottom of the tacks at the bottom of the cup had to be lined up with the battery spokes and observed the magic happen. 

A balanced equation for this experiment was concluded to be 2H20(l) --> 2H2(g) + O2(g). The baking soda (NaHCO3) was not included in this equation because it was not a reactant; it was simply a conductor or electricity through the water. The qualitative evidence to support this reaction was the bubbles we observed because the bubbles indicated the gas that was captured inside the tubes. We observed one tube producing bubbles at a faster rate than the other side and also a universal indicator was added to the solution in the tubes and the tap water on the outside. The class began to see the differences in the colors between the two tubes, indicating different compositions; more specifically, an acid and a base. The quantitative data that proves the balanced equation can be collected by measuring before and after masses of the solution in both tubes. The masses should be the same, proving the balanced equation through the law of conservation of mass. Thanks to my very artistically drawn particle diagram, the equation can be visualized (woohoo) : 

Just the Beginning

Our very first blog addresses our very first lab with our very first objectives:

1. The difference between pure substance and a mixture?

2.The significance of the technique used?

3.Can you mathematically support your conclusion?

4. How can you validate these results?

 The purpose of this lab was to determine if a hydrate was a mixture or a pure substance. Well what's the difference? A pure substance contains only one kind of molecule/atom while a mixture is composed of different pure substances. The significance in the technique we used to test this question was basically how it supported the law of definite proportions... XY + H20(s) --heat--> H20(g) + anhydrous(s). Now, chemistry can be intimidating if math isnt your best subject. BUT have no fear. What this equation means is when heat is applied to a substance combined with water (hydrate), the product is water in the form of gas and a solid substance (anhydrous). The rest is easy, after calculating the percent composition of the anhydrous a conclusion can finally be made. This conclusion can be mathematically supported by the percent composition calculations. If they vary, the hydrate must be a mixture. So of course, if there is a specific percent, it must be a pure substance. I guess Ms. Gardner helped us cheat a little by telling us the percent "we should have gotten": implying the specific percent composition. However, the percents from all 3 groups seemed to be reasonably close to that percent (which was 48.8%). Lastly, validating these results requires calculating percent error. The End (of the beginning).





Matter Classification 
http://schoolsites.schoolworld.com/schools/ThousandIslands/webpages/eoliver/files/matter%20&%20energy.pdf