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Changes to Experiment 2

ACTSCI-FA1HPY

A student is conducting an experiment to determine what factors affect the vapor pressure of methanol. The student is measuring the vapor pressure of methanol using a mercury manometer, as pictured below. The experimental apparatus has an evacuated 1.0 liter bulb, into which the student injects a measured amount of methanol.

The methanol then vaporizes to a gas until the vapor pressure equilibrates with the liquid, by saturating the bulb volume with methanol vapor. The temperature of the methanol is controlled by placing it in a water bath. The student measures the vapor pressure by determining the height of the mercury column after the methanol is injected.

Created for Albert.io. Copyright 2016. All rights reserved.

Experiment 1 Results
The student first tried varying the volume of methanol injected into the bulb.

Created for Albert.io. Copyright 2016. All rights reserved.

Experiment 2 Results
Next, the student tried varying the temperature of a fixed volume of methanol. The student made sure there was always methanol liquid in the glass bulb when the measurement of vapor pressure was taken.

Created for Albert.io. Copyright 2016. All rights reserved.

Experiment 3 Results
Finally, the student tried measuring the vapor pressure of different substances, both with and without alcohol $(-OH)$ groups, at $20° C$.

Which of the following changes to the experimental setup would not have changed the results of Experiment 2?

A

Changing the liquid used from methanol to propanol.

B

Putting in less methanol liquid so that the bulb goes dry as it was heated.

C

Doubling the size of the bulb that the liquid was injected into.

D

Injecting both methanol and ethanol into the bulb.