Question

A scientist measured the properties of a newly synthesized gas molecule. At 55.00 degrees C and 2.090 atm, the specific volume is found to be 0.4947 L/g.

A) Using the ideal gas law, find the molar mass of this molecule.

B) After conducting additional experiments, this scientist measures the critical temperature and pressure of this gas as 308.3 K and 61.4 bar. Was it a good idea in part (A) to assume that the gas was ideal at those conditions?

C) Comparing the physical properties in A and B to known compounds, what molecule do you think this scientist synthesized?

Answer 1

T = 55 + 273 = 328 K

P = 2.090 atm

specific volume = 0.4947 g/L

R = 0.0821 L-atm / mol K

A )

for ideal gas PV = nRT

                    PV = W RT / M

                  P (V/W) = R T / M

                 P Vm = RT / M

                M = RT / P Vm

                M = 0.0821 x 328 / 2.090 x 0.4947

                 M = 26 g / mol

(B) Tc = 308.3 K = 35.3^oC

    Pc= 61.4 bar

so the gas temperature less more then critical temperature . so gas can be compressed . it is not good idea to assume the gas is ideal gas . if the gas is ideal it is very tough task to compress it.

(C) C2H2 gas molar mass = 26 g/mol

     so the gas should be acetylene