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Sucrose (C22O11H22, 342 g mol–1), like many sugars, is highly soluble in water; almost 2000 g will dissolve in 1 L of water, giving rise to what amounts to pancake syrup. Estimate the boiling point of such a sugar solution

User Elhadji
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To estimate the boiling point of a sugar solution, we can use the concept of boiling point elevation, which states that adding a solute to a solvent will increase the boiling point of the solution.

The boiling point elevation (ΔTb) can be calculated using the equation:

ΔTb = Kb * molality

where ΔTb is the boiling point elevation, Kb is the molal boiling point elevation constant for the solvent, and molality is the number of moles of solute per kilogram of solvent.

In this case, sucrose is the solute and water is the solvent. The molal boiling point elevation constant for water is approximately 0.512 °C/m.

Given:
Amount of sucrose dissolved = 2000 g
Molar mass of sucrose (C12H22O11) = 342 g/mol
Volume of water = 1 L (1000 g)
Density of water = 1 g/mL

First, we need to calculate the molality of the sugar solution:

Molality (m) = moles of solute / mass of solvent (in kg)

moles of solute = amount of sucrose dissolved / molar mass of sucrose

moles of solute = 2000 g / 342 g/mol

moles of solute ≈ 5.85 mol

mass of solvent = volume of water = 1000 g

Molality (m) = 5.85 mol / 1 kg

Molality ≈ 5.85 mol/kg

Now we can calculate the boiling point elevation:

ΔTb = Kb * molality

ΔTb = 0.512 °C/m * 5.85 mol/kg

ΔTb ≈ 2.99 °C

Finally, we can estimate the boiling point of the sugar solution by adding the boiling point elevation to the boiling point of pure water, which is 100°C:

Boiling point of the sugar solution = Boiling point of water + ΔTb

Boiling point of the sugar solution ≈ 100 °C + 2.99 °C

Boiling point of the sugar solution ≈ 102.99 °C

Therefore, the estimated boiling point of a sugar solution with almost 2000 g of sucrose dissolved in 1 L of water would be approximately 102.99 °C.
User Nate Petersen
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