Answer:
We should add 15.15 grams of ethylen glycol.
Explanation:
Step 1: Data given
Mass of water = 125 grams
Temperature change = 1.0 °C
The boiling point elevation constant, Kbp, for water is 0.5121 °C/m
Step 2: Calculate mass needed
ΔT = i* Kb * m
⇒ with i = the van't Hoff factor = 1
⇒ with Kb = 0.5121 °c/ kg/mol
⇒ with m = molality = moles / mass
ΔT = i* Kb * m ⇒ 1°C = 0.5121 °C / kg/mol * (X/0.125kg)
X = 0.2441 moles
Step 3: Calculate mass of ethylen glycol
Mass ethylen glycol = moles * molar mass
Mass ethylen glycol = 0.2441 moles * 62.068 g/mol
Mass of ethylen glycol = 15.15 grams
We should add 15.15 grams of ethylen glycol.
