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2017-05-16 8:47 pm
What is the molality of a solution made by adding 235.0 grams of glucose C6H12O6, to 950 grams of water.

Please show work I need this bad. Thanks.
更新1:

I also need the mole fraction of glucose in this question.

回答 (2)

2017-05-16 9:44 pm
Molar mass of C₆H₁₂O₆ = (12.0×6 + 1.0×12 + 16.0×6) g/mol = 180.0 g/mol
No. of moles of C₆H₁₂O₆ = (235.0 g) / (180.0 g/mol) = 1.306 mol

Molar mass of H₂O = (1.0×2 + 16.0) g/mol = 18.0 g/mol
No. of moles of H₂O = (950 g) / (18.0 g/mol) = 52.8 mol

Molality = (No. of moles of C₆H₁₂O₆) / (Mass of H₂O solvent in kg) = (1.306 mol) / (950/1000 kg) = 1.37 m

Mole fraction of C₆H₁₂O₆ = (1.306 mol) / [(1.306 + 52.8) mol] = 0.0241
2017-05-16 9:35 pm
Molar mass of C6H12O6 is 180.1559 g/mol
Mol C6H12O6 in 235.0g = 235.0/180.1559 = 1.304 mol
Molality = mol solute dissolved in 1.0kh solvent
You have 950g water = 0.950kg water
molality = 1.304/0.950 = 1.373 mol /kg
Molality = 1.373m

Mole fraction
Molar mass H2O = 18g/mol
mol H2O in 1,000g = 1,000/18 = 55.556 mol H2O
Total moles in solution = 55.556 + 1.373 = 56.929 mol
Mol fraction
C6+H12O6 = 1.373/56.929 = 0.024
Water = 55.556/56.929 = 0.976
Mol fraction does not have any units.


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