📘 Complete Step-by-Step Solution
🔵 Step 1: Identify the Given Data
Mass of glucose = 18 g
Mass of water (solvent) = 180 g
Molar mass of glucose = 180 g mol⁻¹
Mass of water (solvent) = 180 g
Molar mass of glucose = 180 g mol⁻¹
🟢 Step 2: Calculate Moles of Glucose
The formula for number of moles is:
Moles = Mass ÷ Molar Mass
Moles of glucose
= 18 ÷ 180
= 0.10 mol
= 18 ÷ 180
= 0.10 mol
🟠 Step 3: Convert Mass of Solvent into kg
Molality uses the mass of solvent in kilograms.
180 g = 180 ÷ 1000 kg
= 0.180 kg
= 0.180 kg
🟣 Step 4: Apply the Molality Formula
Molality (m)
= Moles of solute ÷ Mass of solvent (kg)
= Moles of solute ÷ Mass of solvent (kg)
m = 0.10 ÷ 0.180
= 0.5556 mol kg⁻¹
= 0.5556 mol kg⁻¹
🎬 3D-Style Solution Animation
Glucose molecules are dissolved in water.
Glu
H₂O
H₂O
Glu
H₂O
H₂O
18 g glucose → 0.10 mol glucose
180 g water → 0.180 kg solvent
180 g water → 0.180 kg solvent
✅ Final Answer
Molality = 0.5556 mol kg⁻¹
Approximately:
m = 0.556 mol kg⁻¹
Approximately:
m = 0.556 mol kg⁻¹
🎯 Important Formula
Molality (m) =
Moles of solute ÷ Mass of solvent in kg
m = n / W(kg)
m = n / W(kg)
