It takes 192 sec for an unknown gas to diffuse through a porous wall and 84 sec for N_(2) gas to efffuse at the same temperature and pressure. What is the molar mass of the unknown gas?

It takes 192 sec for an unknown gas to diffuse through a porous wall a

1.	It takes 192 sec for an unknown gas to diffuse through a porous wall and 84 sec for N_(2) gas to efffuse at the same temperature and pressure. What is the molar mass of the unknown gas?
Answer» Solution :`(gamma_("unknown"))/(gamma_(N_(2)))= sqrt((m_(N2))/(m_("unknown")))` `(84 sec)/(192 sec) = sqrt((28 g mol^(-1))/(m_("unknown")))=(28 g mol^(-1))/(m_("unknown"))` `m_("unknown") = 28 g mol^(-1) XX ((192 sec)/(84 sec))^(2)` ` m_("unknown") = 146 . 28 g mol^(-1)` .