Question

The molality of a solution that is made by dissolving a certain mass of ethanol in 85.4 g of water is 0.950 m. How many moles of ethanol were dissolved?

0.0811 mol
0.0899 mol
11.1 mol
81.1 mol

Answer 1

A: 0.0811 mol

Step-by-step explanation:

Answer 2

Data:

m (molality) = 0.950 mol/Kg
moles of solute = ? (mol) = ?
mass of solvent = 85.4 g → 0.0854 Kg

Formula:


`m = (moles\:of\:solute)/(mass\:of\:solvent)`

Solving:


`m = (moles\:of\:solute)/(mass\:of\:solvent)`

`0.950\:mol/\diagup\!\!\!\!\!\!K\diagup\!\!\!\!\!\!g = (moles\:of\:solute)/(0.0854\:\diagup\!\!\!\!\!\!K\diagup\!\!\!\!\!\!g)`

`moles\:of\:solute = 0.950*0.0854`

`\boxed{\boxed{moles\:of\:solute = 0.08113 \approx 0.0811\:mol}}`
`\end{array}}\qquad\quad\checkmark`
Answer:
0.0811 mol