A soft keyboard (sometimes called an onscreen keyboard or software keyboard) is a system that replaces the hardware keyboard on a computing device with an on-screen image map.
An ideal gas is defined as one in which all collisions between atoms or molecules are perfectly eleastic and in which there are no intermolecular attractive forces. One can visualize it as a collection of perfectly hard spheres which collide but which otherwise do not interact with each other.
The Ideal Gas Law, as the saying goes, is actually PV=nRT, with all standard variables. Here n=m/M, where m is the mass of the gas and M is the molecular weight of the gas. Now in engineering analysis we often take R/M, compute it and write it as R(bar) (bar meaning a stroke on top of the R).