during an experiment, if not all of a liquid vaporizes, in a flask with a cap with a pinhole. will the reported molecular weight be too high or low?
i was thinking too high because the liquid weighs more.
I need to know more about how the experiment was conducted.
we boiled water in a beaker and put a flask with a small amount of an unknown liquid into the flask then covered it with a lid with a pinhole in it, and we placed this flask in the boiling water bath until the liquid evaporated, then we let it cool and condense.
If I understand what you have done correctly, I think you are correct. The liquid will weigh more than the vapor.
You are correct in thinking that if not all of a liquid vaporizes during an experiment, the reported molecular weight would be too high. Allow me to explain why.
In an experiment involving the measurement of molecular weight, it is usually assumed that the substance being analyzed is completely vaporized in the flask. The molecular weight is determined by measuring the mass of the substance and the volume of the gas it occupies at a known temperature and pressure.
If only a portion of the liquid vaporizes and the remainder remains in the liquid phase, the total mass being measured during the experiment will be higher than expected. This is because the liquid that didn't vaporize will contribute to the overall mass, even though it should not be included in the calculation of molecular weight.
The reported molecular weight is calculated based on the assumption that all of the liquid has vaporized. However, if the liquid doesn't fully vaporize, the observed mass will be higher than it should be, resulting in an overestimate of the molecular weight. Therefore, the reported molecular weight will be too high in this case.
To ensure accurate measurements, it is important to ensure complete vaporization of the liquid before conducting the experiment. This can be achieved by using appropriate heating techniques and optimizing the conditions of temperature and pressure to promote full vaporization.