Fresh molar enthalpy of neutralization for sodium

Category: Technology,
Published: 28.01.2020 | Words: 1444 | Views: 462
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1 . For information regarding the problem, conjecture, materials and procedure, you should see attached

Measurements Table for Molar Enthalpy of Neutralization for Sodium Hydroxide Solution

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Instrument Used


Sodium hydroxide

100mL graduated tube (0. 2mL)

50. 0mL

Sulfuric acidity

100mL managed to graduate cylinder (0. 2mL)

31. 0mL

Heat of salt hydroxide option

Thermometer (0. 2ËC)

twenty six. 0ËC

Temperatures of the sulfuric acid

Thermometer (0. 2ËC)

24. 0ËC

Final heat reached by simply solution

Thermometer (0. 2ËC)

34. 5ËC

Initial and Final Temperatures of Alternatives

Temperature of sodium hydroxide solution (0. 2ËC)

21. 0ËC

Temperatures of the sulfuric acid (0.


24. 0ËC

Final heat reached by simply solution (0. 2ËC)

thirty four. 5ËC

Neutralization Reaction Taking Place

Pre-Lab Computations ” Amount of Sulfuric Acid Needed

Average Initial Temperatures of Solutions Calculation

Fresh Molar Enthalpy of Neutralization for Sodium Hydroxide Remedy Calculation


1 . The experimental large molar enthalpy of neutralization intended for sodium hydroxide solution was found to get

-643. 3KJ/mol.

Calculation of Uncertainties

34. 50. 2ËC ” 25. 00. 2ËC

=9. 50. 2ËC

500. 2mL & 300. 2mL

=800. 2mL

9. 5 0. 4ËC = 4. 210¦%

80 0. 4mL = zero. 5%

40 zero. 2mL = 0. 4%

=5. 11¦%

=5. 1%

Percent Big difference


Through a pre-lab calculation the amount of sulfuric acid option needed was found to become 30.

0m0. 2mL. Employing this information, a calorimetric lab was executed to find the gustar enthalpy of neutralization to get the salt hydroxide option. Through molar enthalpy measurements, the trial and error molar enthalpy of neutralization for the sodium hydroxide solution was found being -64. 03. 3KJ/mol; yet , the assumptive (actual) molar enthalpy of neutralization for the salt hydroxide remedy is -57KJ/mol. In other words the experimental enthalpy change was -64. 03. 3KJ as well as the theoretical (actual) enthalpy alter was -57KJ. This as a result produced a 12% big difference. The various problems will be analyzed in the analysis.


As discussed earlier in the conclusion, the fresh change in enthalpy is higher than the theoretical (actual) difference in enthalpy. This kind of result is fairly rare. Generally, a typical result for the experimental enthalpy change should certainly yield an outcome below the theoretical (actual) value (the basis for this will be discussed later on in the conclusion); however , this did not include the case in this lab. There are a number of main reasons why the experimental enthalpy change for this laboratory was greater than the theoretical (actual) enthalpy change.

Generally, the main reason intended for the result seen in this laboratory is due to the size of the calorimeter. Due to the fact the calorimeter is an isolated environment there is absolutely no possible approach to determine when the reaction is complete. Therefore, the reaction might have been occurring within a concentrated area. With a greater concentration of reactants in one area, the speed of the effect increases combined with the temperature inside the concentrated region. When this heat exchanges to the thermometer, it triggers an increased enhancements made on enthalpy. Normally, the concentration of reactants would be significantly less, as they are certainly not in a concentrated area. This may then create a lower heat increase as there is a smaller chance the allergens will collide. As a result, the change in enthalpy in a typical situation can be much lower than if the reactants were almost all concentrated in one area.

In saying that, it will be easy within this laboratory the reactants were targeted in one area causing the experimental enhancements made on enthalpy being quite large. Because it is not possible to see in the calorimeter to see if the reaction is targeted or if the reaction is definitely complete the reactants can easily have recently been concentrated in a single area. Furthermore, by not being aware of when the reaction is full, the temperatures might be tested too soon or too late creating inaccurate effects. In general, for the reason that calorimeter can be an separated environment this results in the experiment having many mistakes because how the reaction is occurring and when the reaction is finished can be unknown. A method to eliminate this error through inserting an electronic stirring pole to mix the reactants so they do not become concentrated in one location.

Furthermore, another reason contributing to the large enthalpy alter is the impurity of the chemicals used. Consequently, because the substances are contaminated, they would have had a higher concentration of reactants. Having a higher concentration of reactants, the reaction level will increase and there will be a better reaction than wanted. With a larger effect at an increased rate, the last temperature in the solutions can spike more than wanted producing a larger enthalpy change. Consequently, this is a reason contributing to the top enthalpy difference in this research laboratory; however , this reason can be not very significant as the substances can not be so impure the focus on the label is incredibly different then your concentration seen in the bottle (it is illegal to put false information on chemical substances). As a result, the impurity in the substances simply cannot account for all of the errors in this lab. Cleansing the chemicals beforehand may easily eliminate this kind of source of error.

Moving on, there is another reason contributing to the large enthalpy change. The theoretical (actual) value offered is received at SATP conditions; nevertheless , when the pursuing lab was conducted, the conditions were not for SATP. SATP conditions have reached 100kPa and 25ËC. The conditions when the research laboratory was done were by 101. 9kPa and 25ËC.

By raising the pressure, the reaction price is increased and more reactions take place. Because of a larger volume of reactions occurring at information. 9kPa than at the normal SATP conditions, there will be a larger change in enthalpy at tips. 9kPa. This as a result, plays a role in the large difference in enthalpy change noticed in this laboratory; however , just like the previous reason, this is not a tremendous factor in raising the enthalpy change. The pressure differences are not really different to trigger the enthalpy change to enhance to as much as they may have in this lab. As a result, this is a small contributing factor. Performing this lab at SATP conditions is going to eliminate this kind of source of mistake. In general, the reason for the larger enthalpy change is due to not being able to tell if the reaction can be complete and exactly how the reaction is occurring in the calorimeter.

As mentioned previously, the result in this lab is very rare. This is mainly because the Styrofoam calorimeter used to carry out the calorimetric experiment almost certainly does not give a perfectly covered environment. A hole is required to be made to place the thermometer. And there have been many openings between the sport bike helmet of the calorimeter and the calorimeter itself. Due to this ineffectiveness with the Styrofoam calorimeter, some of the high temperature from the effect would have steered clear of through the a large number of holes causing a lower last temperature from the reaction and the experimental enthalpy change to end up being lower than the theoretical (actual) value. Consequently, the trial and error value is normally lower than the theoretical (actual) value.

Another reason includes the simple fact that some of the heat released during the response would have recently been transferred to the calorimeter on its own instead of transferring to the thermometer. As a result, if the calorimeter and/or glass of the thermometer absorb the heat, it causes the thermometer to absorb less heat than it should. The final heat will then be below it should be leading to a lower enthalpy change. Although this is not a main reason why the experimental gustar enthalpy must be lower than using the molar enthalpy it even now contributes to that. As a result, while using combination of these types of factors the experimental enthalpy change ought to be lower than the theoretical value because a lots of heat will be able to escape into the calorimeter and into the atmosphere due to delete word holes in the calorimeter.