Lab

Title of the Lab:  Where's the Evidence? 

The guiding question:  What are some signs that a chemical reaction has taken place? 

Your hypothesis: There could be a change in color, temperature, it could combust, start bubbling or even burn.

List of the Materials used: Spatula, graduated cylinders, stirrer, candle/matches, thermometer, goggles, beakers/ baby food jars, Na2CO3 (Sodium Carbonate), CaCl2 (Calcium Chloride), HCl (Hydrochloric Acid), CuSO4 (Copper Sulfate Acid), Aluminium Foil, Zinc pieces, Baking soda, Vinegar (Acetic Acid), Magnesium Tablets, Iodine and Starch.

Data Table with ALL observations: 

Analysis of your results:

  

1) How do the results of each reaction compare with your prediction? 

- Most of my predictions were correct. Some of the reactions like baking soda and vinegar. I did not expect it to overflow that much.

When we look at the results of all the experiments:

1) How did you know when each reaction was over?

- Usually the fizzing, foaming or bubbling stopped. For other reactions, the two elements separated or one of them dissolved.     

2) What was the evidence of a chemical reaction in all results?

- Sometimes, the state of the element had changed. For example, the sugar and the heat. The evidence of a chemical reaction was the caramelized sugar. Sometimes, the color of the element had changed. For example, the color of the aluminium foil changed when we put it in copper sulfate.

3) Were there any endothermic or exothermic reactions? 

-Sugar and heat was an exothermic reaction because the of the heat. The copper sulfate and sodium carbonate may have been an endothermic reaction because it looked cold and the test tube felt colder than before the reaction.

4) Were the products always the same as what you started with? How do you know?

-No they were not the same because there was a difference in temperature, color and sometimes state. 

Conclusion:

  

We can see that a chemical reaction has taken place when the physical properties of an element are changed. It could be a change in temperature, in color, in state, etc. This is what I thought but some of the experience’s results surprised me. At some point, the reaction stops and we know that when we see that either the foaming, fizzing, bubbling or even color change stops. For some, the two elements separate.

Further Inquiry:  

I found that this lab was interesting but I would have used things that are easier to find and reactions that we can do at home. Otherwise, the lab was fun and I learned new things.