Questions Lab 7

# Questions Lab 7 - in pressure, as most liquids cannot be...

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Questions: Boiling point and density of unknown liquid Name: Liz Zharovsky Bench #: C19 Lab day and section: Tuesday - 2 Q1. Discuss how the atmospheric pressure in the lab could affect your measurements. Answer: The atmospheric pressure in the lab measured in at 774.5 mmHg, which is approximately 1.02 atm. Therefore, we can assume it’s practically standard temperature. If the atmospheric pressure in the lab were significantly higher, then the boiling point would be higher. Similarly, if the atmospheric pressure in the lab were low then the boiling point would be lower. Since the boiling point is the point where vapor pressure equals atmospheric pressure, the vapor pressure will rise with a rise in atmospheric pressure. With a greater vapor pressure, a greater temperature will need to be reached in order for the liquid to boil. This is comparable to various altitudes in the real world, as boiling points of liquids are much lower in the mountains than at sea level. The density of liquids would not be affected by changes
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Unformatted text preview: in pressure, as most liquids cannot be compressed. If the boiling points were different from the normal boiling points because of atmospheric pressure, it would become difficult to correctly identify the unknown liquid as the boiling point would be skewed, as would the calculation of relative error in accuracy of the liquid. Q2 : Q2. Discuss how the volatility of your liquid could affect your measurements. Answer: The more volatile a liquid is, the higher vapor pressure it has, and consequently, the faster it vaporizes. If the liquid’s volatility is elevated when doing density measurements, some of the liquid could vaporize, affecting the volume in the calculation of density. The density would then be lower than the expected value if the liquid was more volatile and allowed to vaporize. With a lower density, the unknown liquid would be difficult to identify because it would veer away from the true value so greatly....
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## This note was uploaded on 01/23/2012 for the course CHEM 18a taught by Professor Dolnik during the Fall '06 term at Brandeis.

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