<span>1)
b(solution) = 1,80 m = 1,80 mol/kg..</span><span>
If we use 1000 g of water to make solution:
m(H</span>₂O) =
1000 g ÷ 1000 g/kg = 1 kg.<span>
n(sucrose - C</span>₁₂O₂₂O₁₁) = b(solution) · m(H₂O).<span>
n(C</span>₁₂O₂₂O₁₁) =
1,8 mol/kg · 1 kg.<span>
n(C</span>₁₂O₂₂O₁₁) =
1,8 mol.<span>
n(H</span>₂O)
= 1000 g ÷ 18 g/mol.<span>
n(H</span>₂O)
= 55,55 mol.<span>
Mole fraction of solvent = 55,55 mol ÷
(55,55 mol + 1,8 mol) = 0,968.
Raoult's Law: p(solution) = mole fraction of solvent · p(solvent).
p(solution) = 0,968 · 17,54 torr = 16,99 torr.
Δp = 17,54 torr - 16,87 torr = 0,55 torr.</span>
2) b(solution) = 1,80 m = 1,80 mol/kg..<span>
If we use 1000 g of water to make solution:
m(H</span>₂O) =
1000 g ÷ 1000 g/kg = 1 kg.<span>
n(NaCl</span>) = b(solution) · m(H₂O).<span>
n(NaCl</span>) = 1,8 mol/kg · 1 kg.<span>
n(NaCl</span>) = 1,8 mol.<span>
n(H</span>₂O) =
1000 g ÷ 18 g/mol.<span>
n(H</span>₂O) =
55,55 mol.<span>
i(NaCl</span>) = 2; Van 't Hoff factor. Because dissociate on one
cation and one anions.
Mole fraction of solvent = 55,55 mol ÷
(55,55 mol + 1,8 mol · 2) = 0,94.
<span>
Raoult's Law: p(solution) = mole fraction of
solvent · p(solvent)
p(solution) = 0,94 · 17,54 torr = 16,47 torr.
Δp = 17,54 torr - 16,47 torr = 1,06 torr.</span>
