A piece of solid carbon dioxide, with a mass of 21.0 g, is placed in an otherwise empty 4.60 L container at 25°C. What is the pressure in the container after all the carbon dioxide vaporizes?

T = 298.5K

               V = 4.60L

                m(CO2) = 21.0g

finding moles  carbon dioxide :  n = m/Mr

                                                           = 21g / 44.01 g/mol

                                                            = 0.477 mol

then use P = nRT/ V

                   =   0.477 mol × 0.0821 × 298.5k/ 4.60 L

                    = 2.54atm

Explanation: pressure can be determined by first finding the number of moles of carbon dioxide.We then deduce the ideal gas formula that provide the the relationship between volume, temperature,pressure and the number of particles in the gas.the equation only makes easier for assumptions which in most cases are not true