Question

Question #7be8c

Answer 1

The pressure would be 1029 Torr.

Explanation:

Henry’s law says that the concentration `c` of a gas in a solvent is directly proportional to the partial pressure `p` of the gas above the solvent.

The mathematical expression for Henry’s law is

`color(blue)(bar(ul(|color(white)(a/a)c = k_text(H)pcolor(white)(a/a)|)))" "`

where `k_text(H)` is is a proportionality constant called the Henry's Law constant.

If we have the same solute in the same solvent at two different pressures `p_1` and `p_2`, we can write

`c_1 = k_text(H)p_1`

and

`c_2= k_text(H)p_2`

Dividing the two equations, we get

`c_1/c_2 = (color(red)(cancel(color(black)(k_text(H))))p_1)/(color(red)(cancel(color(black)(k_text(H))))p_2) = p_1/p_2`

∴ `p_2 = p_1 × c_2/c_1`

The volumes of solvent are the same, so we can use the masses of the solute instead of concentrations.

∴ `p_2 = "772.0 Torr" × (0.4960 color(red)(cancel(color(black)("g"))))/(0.3720 color(red)(cancel(color(black)("g")))) = "1029 Torr"`