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Zat a terbuat dari 15 gr A2B yang terionisasi sempurna dicampur dengan zat b terbuat dari 120 gr urea (mr=60) dalam 1000 gr air. jika campuran ini memiliki titik didih 102 oc dan tetapan titik didih air = 0,5 oc/m. Hitung nilai berat molekul A2B…..gr/mol
Accepted Answer
The molecular weight of A2B is 150 g/mol. Here's how to solve it:
1. Calculate the molality of the solution:
- ΔTb = Kb
m
- 2 = 0.5
m
- m = 4 mol/kg
2. Calculate the total moles of solute:
- moles of solute = molality
mass of solvent (in kg)
- moles of solute = 4 mol/kg
1 kg = 4 mol
3. Calculate the moles of urea:
- moles of urea = mass of urea / molar mass of urea
- moles of urea = 120 g / 60 g/mol = 2 mol
4. Calculate the moles of A2B:
- moles of A2B = total moles of solute - moles of urea
- moles of A2B = 4 mol - 2 mol = 2 mol
5. Calculate the molar mass of A2B:
- molar mass of A2B = mass of A2B / moles of A2B
- molar mass of A2B = 15 g / 2 mol = 7.5 g/mol
6. Since A2B is the formula, the molecular weight is:
- Molecular weight of A2B = 7.5 g/mol
2 = 15 g/mol
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