For the ideal gas law and van der waals eq'n, R can be a) 8.3145J/(k*mol) or b) 0.082058(L*atm)/(k*mol) . But if I use the first value of R, and try to solve for P my value always comes out as about 1000 smaller than it should be in Pa(ie/ it should be 2000 but it gives me 2). If I use the 2nd value, my value comes out in atm which is okay. But I cant use this value in another eq'n I need, so I don't want to use it. Is the ideal gas law supposed to be in kPa?