Answer:
Molarity of acetone: 0.68 M
Mole fraction acetone: 1.17 / 18.37 = 0.063
Explanation:
First of all, think in this data: 1.17 m. This is molal.
Molality means moles st / 1kg solvent so 1.17 moles are in 1 kg of ethanol.
Second step: Use Density to get volumen
Density = mass /volume
Ethanol density = Ethanol mass / ethanol volume
0.789 g/ml = 1000 g / volume ethanol
Volume ethanol = 1000g / 0.789 g/ml = 1267.4 ml
1.17, as we saw, are moles. A mass in g that we can obtained from the molar weight.
Molar weight acetone: 58.08 g/m
Moles . molar weight = mass → 58.08 g/mol . 1.17 mol = 67.9 g
Now let's use density
Acetone density = Acetone mass / Acetone volume
0.788 g/ml = 67.9 g / volume acetone
Volume acetone = 86.2 ml
Assume that the volumes of acetone and ethanol add
86.2 ml + 1267.4 ml = 1353.6 mL .- This is the volume of solution.
Molarity means moles of solute/L of solution. Let's think the rule of three:
1353.6 mL __ we have __ 1.17 moles
1000 mL ___ we have ___ (1000 . 1.17)/ 1353.6 = 0.86 M
For mole fraction, we need to know the moles of acetone.
Molar weight acetone 58.08 g/m
Mass / Molar weight : moles
1000 g / 58.08 g/m = 17.2 moles
Mole fraction acetone : acetone moles / total moles
Total moles: 17.2 + 1.17 = 18.37 moles
Mole fraction acetone: 1.17 / 18.37 = 0.063
