資料紹介

*Aim
According to Hess’s law, the heat of reaction of the one reaction should be equal to the sum of the heats of reaction for the other two. Measure the heat released by 3 reactions by using a Styrofoam-cup to than calculate for the heat of reaction, ΔH, for the 3 reactions. Use the results to confirm Hess’s law.


*Conclusion
Actually we couldn’t show that the {ΔH (kJ) / mol} of H2O + NaOH (s) and {ΔH (kJ) / mol} of 1.0M HCL + 1.0M NaOH (aq) ‘s sum will become {ΔH (kJ) / mol} of 0.50M HCL + NaOH (s). I got -65.63kJ/mol ±1.04% instead of “Expected value; -89.41kJ/mol”. So I think there must some error in our experiment or I mistook the calculation in somewhere. Also the solid NaOH were difficult to handle with it so, I think the most error were occurred at that point. Solid NaOH continuously absorbing water from the air so it’s must have some extra water in the liquid.

*Evaluation
As I wrote in the conclusion, biggest problem about this lab is about solid NaOH. The solid NaOH can absorb water very quickly and also continuously. For our experiment, we have to…
1.Take out solid NaOH
2.Weigh the mass
3.Bring back to own table
4.Finally, put into cup, using spoon or etc.
So in this period, I think some water is absorbed into solid NaOH and I think that could be made our result weird.

資料の原本内容 ( この資料を購入すると、テキストデータがみえます。 )

*Heats of Reaction:
Hess’s Law
*Aim
According to Hess’s law, the heat of reaction of the one reaction should be equal to the sum of the heats of reaction for the other two. Measure the heat released by 3 reactions by using a Styrofoam-cup to than calculate for the heat of reaction, ΔH, for the 3 reactions. Use the results to confirm Hess’s law.
*Materials & Procedures
Please look in the attachment.
*Data Collection & Processing ・Observation for chemical materials:
Material’s name O b s e r v a ...

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