Question

an unknown gas occupies a volume of 4.75L at 1227degrees Celsius and 5.00atm. if the mass is 5.45g, what is the molar mass of the gas?

Answer 1

Data given :       Volume =4.75 Litre

                        Temperature = 1227 ^oC =1227+273= 1500 k

                       Pressure = 5 atm

                       weight = 5.45 grams

          We will use the ideal gas law to find the molar mass

         Ideal gas law is given by,

        PV=NRT

Where, P= pressure

        T= Temperature

       V=volume

       N= number of moles

      R = ideal gas constants = 0.0821 L atm K^-1 Mole^-1

      Substituting all the values in the ideal gas law

            5*4.75 = N * 0.0821 * 1500

               N = 0.19285 moles

            Now we know weight of the gas =5.45 g

         therefore, molecular weight = weight of gas/ moles of gas = 5.45/0.19285 = 28.26 g/mole

          Hence, molar mass of the gas is 28.26 g/mole