While gas fron a cooking gas cylinder is used, the pressure does not fall appreciably till the last few minutes. Why?

Do you expect the gas in a cooking gas cylinder to obey the ideal gas equation?

Inside a certain automobile engingen, the valume of air in a cylinder is 0.475 dm^(3) , when the pressure is 1.05 atm . When the gas is compressed, the pressure increased ato 5.65 atm. At the same temperature. What is the volume of compressed air ?

____gas cylinders are used for breathing purpose for a diver going deep into the sea.

In defining the ideal gas temperature scale, It is assumed thet the pressure of the gas at constant volume is proportional to the temperature T. How can we verify wheter this is true of not? Are we using the kinetic theory of gases? Are we using the experimental result that the pressure is proportional to temperature?

The heights of mercury surfaces in the two arms of the manometer shown in figure are 2 cm and 8cm. Atmospheric pressure =1.01xx10^5Nm^-2 . Find (a). the pressure of the gas in the cylinder and (b). the pressure of mercury at the bottom of the U tube.