GS #3 PS section #6

[yjj8817]

6) The likely explanation for choosing flexible tubing in the apparatus in Figure 1 is so that:

1. the gas will experience varying pressure while the change of volume can be measured in the glass tubing.
2. the gas will experience varying pressure while the change of volume can be measured in the glass bulb containing mercury.
3. the gas will be maintained at atmospheric pressure while the change of volume can be measured in the glass tubing.
4. the gas will be maintained at atmospheric pressure while the change of volume can be measured in the glass bulb containing mercury.

INCORRECT:

Your Answer: D
Correct Answer: C

I don't quite understand how this apparatus works. Why does the glass bulb with the mercury decrease in height when volume of gas increases due to temperature? Is it because the increase in volume of gas leads to change in pressure of gas so does lowering the glass bulb with the mercury maintain constant temperature?

Thanks!

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[Cawolf]

If the gas is at constant pressure, then increasing the temperature will cause it to expand. Expansion of the gas will force the mercury farther away, or lower down the glass piping. The mercury will flow into the bulb, so it will remain at constant temperature.

The main takeaway is that changing volume in the gas due to temperature effects the position of the mercury.

 

[Labrat07]

I picked D as well. @Cawolf Why is the answer not D?? I understand change in temperature = change in volume. In this case the mercury.

 

[Cawolf]

@Labrat07

It does not seem to be easily quantifiable given the flexible nature of the tubing.

I always pick the answer that seems to make the most sense. Measuring the change in height seemed the most natural.

 

[Labrat07]

I see your logic. That make a lot of sense. Thank you.