Can the volume of a gas be measured? Yes, just the measure the volume of the container it is in. No, the volume will always be different so it is inaccurate. No, gas is soluble in liquid so it cannot be determined. Yes, the volume can be calculated once the mass is determined.

It depends on if you want the volume of the gas itself which is impossible to calculate because it changes based on the container it is in, but if you want to find the volume of the gas in relation to the container it is in then it is possible and fairly easy to do, can you calculate the volume of a gas technically yes you can but it will always be different if you change the container it is in