How Does The Temperature Change From Hydrochloric Acid To Evaporate
As a liquid evaporates, it lowers the temperature of the substances around them, because evaporation is an endothermic process. In the graph, each substance has a different curve. Some lowered the temperature much more than others. This is because different substances require differing amounts of energy to evaporate. To test this, the temperature change from the evaporation of 4 different alcohols was measured and compared, along with cyclohexane. Methanol had the largest change in temperature, 18.9 ºC. This indicates that methanol has the weakest intermolecular attractions out of the 4 alcohols, because it evaporated the most. This may be because methanol is a small molecule so it has less electrons and therefore is not as polarizable as
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This affects the intermolecular attractions because the more polar a molecule is the stronger its attraction to other polar molecules will be. The next two alcohols were ethanol and propanol which followed the predicted pattern at 13.2 ºC and 5.3 ºC respectively. Butanol had the smallest change in temperature, 2.5 ºC which indicates much less evaporation. This leads to believe that butanol has the strongest intermolecular forces of the 4 alcohols tested. This is supported by the fact that butanol is the largest of the four, and has the most electrons, and therefore is the most polarizable. Interestingly, water has stronger intermolecular forces than methanol, despite methanol having more polarizable electrons. This is because water has more hydrogens available to pair with oxygens, whereas the hydrogens in methanol are mostly bonded to carbons and therefore not positive enough to create a hydrogen bond. In the diagrams drawn below, it is apparent that water can create 4 hydrogen bonds and methanol can only create 3, therefore, water has stronger intermolecular attraction. A substance not yet mentioned was also tested. Cyclohexane had a 10.5 ºC temperature change, despite being much larger than butanol. Butanol and propanol have stronger intermolecular forces than cyclohexane because of their ability to hydrogen bond. Cyclohexane relies entirely on London Dispersion forces, but the alcohols can have a hydrogen
This affects the intermolecular attractions because the more polar a molecule is the stronger its attraction to other polar molecules will be. The next two alcohols were ethanol and propanol which followed the predicted pattern at 13.2 ºC and 5.3 ºC respectively. Butanol had the smallest change in temperature, 2.5 ºC which indicates much less evaporation. This leads to believe that butanol has the strongest intermolecular forces of the 4 alcohols tested. This is supported by the fact that butanol is the largest of the four, and has the most electrons, and therefore is the most polarizable. Interestingly, water has stronger intermolecular forces than methanol, despite methanol having more polarizable electrons. This is because water has more hydrogens available to pair with oxygens, whereas the hydrogens in methanol are mostly bonded to carbons and therefore not positive enough to create a hydrogen bond. In the diagrams drawn below, it is apparent that water can create 4 hydrogen bonds and methanol can only create 3, therefore, water has stronger intermolecular attraction. A substance not yet mentioned was also tested. Cyclohexane had a 10.5 ºC temperature change, despite being much larger than butanol. Butanol and propanol have stronger intermolecular forces than cyclohexane because of their ability to hydrogen bond. Cyclohexane relies entirely on London Dispersion forces, but the alcohols can have a hydrogen