Experiment 4B - Enthalpy of Vaporisation of Ethyl Acetate PDF

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Enthalpy of Vaporisation of Ethyl Acetate...

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Experiment 3B – Enthalpy of vaporisation of ethyl acetate Results and Analysis: A spectrometer was fixed at 210nm, where 12 samples of ethyl acetate were run for 10 measurements at 1 minute intervals. Table 1: Absorbance measured at various temperatures and calculated standard deviation at 210nm

Temperature °C 20 22.5 25 27.5 30 Temperature K 293.15 295.65 298.15 300.65 303.15 Measurement Absorbance Absorbance Absorbance Absorbance Absorbance 0 0.29037 0.29795 0.36039 0.42039 0.48155 1 0.28585 0.29628 0.36027 0.41921 0.48376 2 0.2808 0.29446 0.36175 0.42076 0.48357 3 0.27643 0.29263 0.36141 0.42277 0.48206 4 0.27229 0.29143 0.36044 0.42048 0.48242 5 0.26738 0.28981 0.35951 0.42069 0.48283 6 0.26279 0.28796 0.35906 0.42314 0.48322 7 0.25864 0.28673 0.35848 0.42301 0.4835 8 0.2547 0.28526 0.35765 0.42188 0.48396 9 0.2515 0.28311 0.3569 0.42199 0.48325 10 0.24853 0.28109 0.35639 0.42063 0.48324 Average 0.268 0.290 0.359 0.421 0.483 absorbance Average 0.268 0.290 0.359 0.421 0.483 absorbance Standard 1.42E-02 5.43E-03 1.78E-03 1.27E-03 7.47E-04 deviation The calculated standard deviations are extremely low, indicating precise results and not so many errors. Sx =

standard deviation √10

Error in 𝑙𝑛(𝐴) = Sy = (

1

) × Sx

𝑙𝑛(𝐴)

Table 2: Calculated 𝑆𝑥 𝑎𝑛𝑑 𝑆𝑦

Sx Sy

4.49E-03 -3.41E-03

1.72E-03 -1.39E-03

5.62E-04 -5.49E-04

4.03E-04 -4.66E-04

2.36E-04 -3.25E-04

Table 3: Data for ln(A) versus 1/RT

Average absorbance 0.268 0.290 0.359 0.421 0.483

1/RT

ln(A)

0.0004103 0.0004068 0.0004034 0.0004001 0.0003968

-1.317 -1.238 -1.024 -0.865 -0.728

Error in ln(A) Sy -3.41E-03 -1.39E-03 -5.49E-04 -4.66E-04 -3.25E-04

A graph was plotted ln(A) versus 1/RT (K). 0.000 0.0003960.0003980.00040.0004020.0004040.0004060.0004080.000410.000412 -0.200 -0.400

ln(A)

-0.600 -0.800 -1.000 -1.200 -1.400

-1.600

1/RT

y = -45814x + 17.451

Figure 1: ln(A) versus 1/RT (K)

From the equation that has been derived from the graph, the slope (m) is equal to the Hvap of ethyl acetate. Conclusion 12 samples of ethyl acetate were run for 10 measurements at 1 minute intervals, the spectrometer was fixed at 210 nm. Hvap was calculated to be − 45.814 𝑘J/mol...