Which of the following gases will have least volume if 10g of each gas is taken at same temperature and pressure?

Which of the following gases will have least rms speed at a given temperature?

At a particular temperature and pressure, the volume of 12 g of H_2 gas is 134.5 L. what will be the final volume of the gas if 4 g of H_(2) gas is added to it at the same temperature and pressure?

At a given temperature and pressure, the volume of 1 mol of an ideal gas is 10 L. at the same temperature and pressure, the volume of 1 mol of a real gas is VL. At this temperature and pressure, if the compressibility factor of the real gas is greater than 1, then -

At a given temperature annd pressure, the volume of 10 g of He gas is 61.6 L. how much of He gas has to be taken out at the same temperature and pressure to reduce its volume to 25 L?