Answer:
[tex]m_{solute}=8.6g[/tex]
Explanation:
Hello,
In this case, the unit of concentration is molality which is defined by:
[tex]m=\frac{n_{solute}}{m_{solvent}}[/tex]
Whereas the mass of the solvent is measured in kilograms. In such a way, with the given data, we first compute the kilograms of water:
[tex]m_{solvent}=250g*\frac{1kg}{1000g} =0.25kg[/tex]
Then, we solve for the moles of the solute:
[tex]n_{solute}=0.75\frac{mol}{kg}*0.25kg =0.19mol[/tex]
Finally since the molar mass of ethanol is 46 g/mol, we compute the grams for the given solution:
[tex]m_{solute}=0.19*\frac{46g}{1mol} \\\\m_{solute}=8.6g[/tex]
Best regards.