Acylinder, with a piston pressing down with a constant pressure, is filled with 1.90moles of a gas (n1), and its volume is 48.0l (v1). if 0.800mole of gas leak out, and the pressure and temperature remain the same, what is the final volume of the gas inside the cylinder?

and

a sample of gas in a cylinder as in the example in part a has an initial volume of 70.0l , and you have determined that it contains 2.00moles of gas. the next day you notice that some of the gas has leaked out. the pressure and temperature remain the same, but the volume has changed to 17.5l . how many moles of gas (n2) remain in the cylinder?