the boiling point increased by 2oC, what is the approximate molality of NaCl.
K boiling point(water)= 0.512oC/m
delta T = i*Kb*m
delta T = 20
Kb = 0.512
i for NaCl = 2
m = ?
To find the approximate molality of NaCl, we can use the formula:
ΔTb = Kbp * m
where:
ΔTb is the change in boiling point,
Kbp is the molal boiling point constant, and
m is the molality.
Given that the change in boiling point (ΔTb) is 2°C and the molal boiling point constant (Kbp) for water is 0.512 °C/m, we can rearrange the formula to solve for m:
m = ΔTb / Kbp
m = 2°C / 0.512 °C/m
Now, we can calculate the molality:
m ≈ 3.91 mol/kg (rounded to two decimal places)
Therefore, the approximate molality of NaCl is approximately 3.91 mol/kg.