Lab Report Reactivity

Results:

With 0.1mol HCl:

Table 1.0

With 1mo HCl:

Table 1.1

Data processing: 

In this experiment, we saw how the Tº of a mixture between a metal and HCl changed due to the reactivity of the metal, or its ability to donate an electron. Elements with fewer electrons on its outer shell will tend to donate them easier than those with more in it, so will react faster and easier, causing a rise in temperature.

With some observations, we noted that Copper dissolved almost nothing, while Magnesium did completely. This is because Mg had 3 electrons in its outer shell and its ability to donate electrons was higher than Copper. Mg, finally was the most reactive, changing 5ºC ± 1ºC in the reaction with a 0.1mol HCl, and 8ºC ± 1ºC with the 1mol one. Iron’s change in Tº was 2ºC ± 1ºC, Copper’s and Zinc’s were the same: 1ºC ± 1ºC, and Aluminium’s was 0ºC ± 1ºC.

Finally the reactivity trend gave us:

Mg<Fe<Cu=Zn<Al

While the theoretical result is instead:

Mg<Al<Zn<Fe<Cu

Errors:

• Stirring was not constant and equal in every mixture.
• We didn’t let the reaction enough time for the metal to dissolve completely.
• Some heat escaped through the polystyrene cup’s holes.
• Measurement errors, systematical errors (indicated each one in “Materials”).
• Not exactly 1g of each metal was used.
• Thermometer wasn’t in the original temperature when started the next experiment with the next metal.
• We used two different molarities of HCl and so even if we repeated the experiment twice, we didn’t get accurate results because we couldn’t make an average.
• Maybe metals or HCl weren’t pure.

Improvements:

• Do not stir, or try to do it constantly.
• Leave the reaction alone for about 10 minutes.
• Fill any hole of the polystyrene cup with plasticine.
• Try to read the thermometer in the straightest position so as to read it the most perpendicularly possible, and the more accurate.
• Weight metals so as to use the same mass of each in each experiment.
• Let the thermometer cool down to its original Tº or use six different ones.
• Repeat the experiment several times with the same molarity of HCl.

Conclusion:

The results were not as expected due to many errors. We repeated the experiment twice and in both cases we got the same material being the most reactive and vice versa, but our errors were in both cases the same, and we got the same trend in both cases. The most probable explanation is that substances weren’t pure enough.