How many grams of salt must be added to 300g of water to increase its boiling point by 5°C?
You must add 86 g of salt.
The formula for boiling point elevation is
#color(blue)(|bar(ul(ΔT_"b" = iK_"b"m)|)#
#i#is the van't Hoff factor #ΔT_"b"#is the boiling point elevation #K_"b"#is the boiling point elevation constant #m#is the molality of the solution
We can solve the equation for the molality of the solution.
In this problem,
Next, we calculate the moles of
The formula for molality is
#color(blue)(bar(ul(|color(white)(a/a) "Molality" = "moles of solute"/"kilograms of solvent"color(white)(a/a)|)))" "#
Finally, convert moles of