Problem : 1.00 mol of ammonia fills a 7.00 liter bottle at 350 K. What does the van der Waals equation predict that the pressure will be? For ammonia a = 4.17  and b = 0.0371 L/mol.

Rearrange van der Waals equation to find pressure:


P= -  
 = -  
 =4.04 atm  

Problem : How much volume would 1.00 mole of CH4 molecules take up if they were stacked on each other? bCH4 = 0.04278 L/mol

Volume = nb. 1.00 mol×bCH4 = 0.04278  = 0.0428 L Keep in mind that, under ideal conditions, 1 mol of methane gas would occupy 22.4 L.