Question

How many grams of lithium sulfate (`Li_2SO_4`) are required to dissolve in 459 g of water to make a 1.23 m solution?

Answer 1

I assume you want `"molal"` NOT `"molar"` concentration.

Explanation:

We want a `1.23*mol*kg^-1` solution with respect to `Li_2SO_4`. Here, we deal with a molal concentration.

`"moles of lithium sulfate"/"kilograms of solvent"` `=` `1.23*mol*kg^-1`

Thus `"moles of lithium sulfate"`

`=` `0.459*kgxx1.23*mol*kg^-1` `=` `0.565*mol`

We require a mass of `0.565*molxx109.94*g*mol^-1` `=` `62.12*g`.

This site reports the solubility of lithium sulfate in water. I have not gone thru it. Your given problem may be physically unrealistic.