Confused about the volume of a rigid (glass) container

[sp3sp2sp]

Homework Statement

This is for a lab report and I am just confused about how I should regard volume because this issue is affecting 3 other questions. If you heat a gas in a closed flask that is connected to a manometer with water in it, the water level goes up (the arm open to atmosphere rises and arm connected to flask goes down). But it now asks about the volume, as I heat the gas. Does it change? Its a glass flask so obviously the volume in flask won't or can't change but the gas excerts pressure through a rubber tube connected to arm of manometer and that causes water level to rise.
So should I consider that the Volume of the gas does change? Because the gas has expanded into the tubing right? ..Or should I say V of gas does not change? Because the gas is in a rigid container that has fixed volu?

I know that increased T will increase P if V kept constant and that if P kept constant V must increase to compensate. But I don't understand how I should regard the gas in this apparatus. Is it constant or not?
Thanks for any help

Homework Equations

The Attempt at a Solution

 

[Ygggdrasil]

Generally, you can assume that the change in volume due to the manometer should be negligible compared to the total volume of the flask.

 

[Nik_2213]

Hi ! A couple of thoughts...

A volumetric flask is calibrated at a specific temperature, usually 20'C, due to expansion, resulting flexing etc. There will not be much change around ambient conditions, but be aware and log the temperature for reference.

When we tested 'collapse revival' ampoules and collected the gas in a manometer, beside correcting for ambient temperature and atmospheric pressure, we levelled the menisci to equilibrate internal and external pressures...