Results Only Lab Report IMF, discussion, table and graphs PDF

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Summary

Probes were broken so we did it with regular thermometers. Might not include the full data because of this. Graphs and tables are accurate...

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Experiment #1: IMF (On-Campus Lab)

Thalia Sarmiento Lab Partners General Chemistry I (D03) Professor Richard H. Perry Laboratory Assistant 8/15/21

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Results/Data Data acquired during the experiment: Substance T-max(°C) TΔT(°C) min(°C) Ethanol 22 12 10 24 17 7 1-Propanol Table# 1: Temperature changes during evaporation of Ethanol and 1- Propanol Substance Methanol Pentane

T-max(°C)

T-min(°C) ΔT(°C) 23 7 16 21 -5 26

Table# 2: Temperature changes during evaporation of Methanol and Pentane Substance Ethanol(C2H6O) 1Propanol(C3H8O) Methanol (CH3OH) Pentane(C5H12)

Molecular Weight 46.048 60.064

ΔT(°C) 10 7

32.032 72.096

16 26

Table# 3: Temperature changes calculated and molecular weight of selected molecules.

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Data Given: Table #4: Temperature change during evaporation Substance Trial Tmax (°C) Tmin (°C) ΔT (°C) (Tmax- Tmin) Ethanol 1 21.9 11.1 10.8 1-Propanol 1 22.4 14.9 7.50

Table #5: Comparing and predicting temperature changes during evaporation. Trial T-max(C) T-min (C) ΔT(C) (T-max-T-min) 1 25.7 7.50 18.2 1 23.8 20.9 2.90 1 17.4 4.50 12.9 1 19.5 6.90 12.6 1 21.5 0.20 21.3 1 23.3 16.3 7.00

Figure#2: Change in temperature vs. molecular weight of alkenes, alcohols and others 25 20

Δ T (C)

Substance Methanol 1-Butanol Pentane Hexane Acetone Water

Average (°C) 10.8 7.50

15 10 5 0

0.00

20.00

40.00

60.00

80.00

100.00

Molecular Weight (g) Methanol

1-Butanol

Pentane

Calculations 1. Change in Temperature for Ethanol: 22°C- 12 °C= 10 °C 2. Change in Temperature for 1- Propanol 24°C- 17 °= 7°C 3. Change in Temperature for Methanol 23°C- 7°C= 7°C 4. Change in Temperature for Pentane 21°C-(-5°C) = 26 °C 3

Hexane

Acetone

Water

Average(C) 18.2 2.90 12.9 12.6 21.3 7.00

5. Molecular Weight of Ethanol (12*2) +(1.008*2) +16= 46.048g C2H6O 6. Molecular Weight of 1- Propanol: (12*3) +(1.008*8) +16= 60.064 g C3H8O 7. Molecular Weight of Methanol: 12+(1.008*3) +16+1.008= 32.032g CH3OH 8. Molecular Weight of Pentane: (12*5) +(1.008*12) = 72.096 g C5H12

Results (ONE CONCISE PARAGRAPH) The purpose of this experiment was to correlate the strength of Intermolecular Forces and other characteristics such as molecular weight of substances to properties such as evaporation and freezing. It was determined that there are many examples of intermolecular forces, but the main ones observed in this lab were hydrogen bonds and dipole-dipole. At the beginning of the experiment, it was hypothesized that the molecules that would have had a bigger change in temperature have weak intermolecular forces, while the ones that had a smaller value will have stronger bonds between the elements. Using this notion, it was predicted that ethanol will have a small temperature change, since it is an alcohol and it contains an OH group that has hydrogen bonding, making it harder to break the bonds. Secondly, 1- propanol was predicted to have a small change in temperature since it is also an alcohol and contains an OH group which means it contains hydrogen bonding. Thirdly, methanol was predicted to have a small change in temperature since an OH group is present and is also alcohol. Finally, pentane was hypothesized to have a large temperature change, because of the molecule's structure and charges, there are only dispersion forces present. These intermolecular forces are very weak and easy to break which will lead to an increase in the temperature change. To determine which alcohol will have the smallest and largest change in temperatures, molecular weight was also considered. Since 1- propanol has the largest molecular weight and methanol has the lowest, it was predicted that methanol will have the highest temperature change out of all the alcohols, followed by ethanol and then 1- propanol. According to the data recorded during the experiment, all the hypotheses were supported. Pentane was the molecule with the highest ΔT with a difference between values of 26  C (Table #1). Out of all the alcohols 1- propanol showed the lowest ΔT only having a difference of 7 C, followed by ethanol which had a ΔT of 10 and then methanol which had the highest ΔT of the alcohols at 16  C. (Table #1 and #2).

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Post Lab Questions: In the space below, organize your samples from smallest ΔT to largest ΔT for your alkanes, and again for your alcohols: Alkanes: _______Hexane______________ < _______Pentane______________ Alcohols: ___1-Butanol_...