Question

Hydrogen has two naturally occurring isotopes, 1H and 2H. Chlorine also has two naturally occurring isotopes, 35Cl and 37Cl. Thus, hydrogen chloride gas consists of four distinct types of molecules: 1H35Cl, 1H37Cl, 2H35Cl, and 2H37Cl. Place these four molecules in order of decreasing rate of effusion. Rank molecules from highest rate of effusion to lowest. To rank items as equivalent, overlap them.

Answer 1

The order of effusion from highest to lowest will be:

`^1H^(35)Cl` >
`^2H^(35)Cl` >
`^1H^(37)Cl` >
`^2H^(37)Cl`

Step-by-step explanation:

Isotopes of hydrogen ;
`^1H` and
`^2H`

Isotopes of chlorine ;
`^(35)Cl` and
`^(37)Cl`

Mass of
`^1H` = 1 g/mol

Mass of
`^2H` = 2g/mol

Mass of
`^(35)Cl` = 35 g/mol

Mass of
`^(37)Cl` = 36 g/mol

Mass of
`^1H^(35)Cl` = 1 g/mol+35 g/mol =36 g/mol

Mass of
`^1H^(37)Cl` = 1 g/mol+37 g/mol =38 g/mol

Mass of
`^2H^(35)Cl` = 2 g/mol+35 g/mol =37 g/mol

Mass of
`^2H^(37)Cl` = 2 g/mol+37 g/mol =39 g/mol

Graham's law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows the equation:

`\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}`

Decreasing order of masses :

`^2H^(37)Cl` >
`^1H^(37)Cl` >
`^2H^(35)Cl` >
`^1H^(35)Cl`

So, the order of effusion will be revered :

`^2H^(37)Cl` <
`^1H^(37)Cl` <
`^2H^(35)Cl` <
`^1H^(35)Cl`

The order of effusion from highest to lowest will be:

`^1H^(35)Cl` >
`^2H^(35)Cl` >
`^1H^(37)Cl` >
`^2H^(37)Cl`