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| Pre-Lab Table |
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| My Data Table |
2. There was a wide range of temperature differences as shown in my data table above. Even though all of the substances had the same intermolecular attractive force, some substances had stronger forces than others. A substance with weaker hydrogen bonds (even though it is not an actual bond) will evaporate faster, which leads to a larger temperature difference and higher vapor pressure. Evaporation is a process that involves the use of energy which is why the temperature of the substance often decreases as it loses energy. The more a substance evaporates, the more energy it used and the lower the minimum temperature will be.
3. In this particular lab, Ethanol (molar mass= 46.068) and Methanol (molar mass= 32.0416) were the two compounds with similar molar masses. After experimentation, we found Methanol had the quicker evaporation rate and the larger temperature difference. This result was expected because Ethanol does have a slightly larger molar mass than Methanol. A larger molar mass indicates a substance contains more electrons and a greater number of electrons increases the strength of a substances intermolecular forces. A compound with stronger forces needs more energy to evaporate and therefore it is took less energy for Methanol to evaporate compared to Ethanol.
4. Hydrogen bonds are the strongest type of covalent bonds. The more hydrogen bonds a substance contains, the more energy it needs to break and change in the form of evaporation. In this lab, Glycerin contained the most amount of OH- groups and therefore it needed the most energy to evaporate. Our data shows how Glycerin actually increased in temperature because it was absorbing heat from the room rather than evaporating.
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