An aqueous solution of ethanol has density 1.025g/mL and it is 2M. What is the molality of this solution?

1000mL solution contain 2 mole of ethanol or $1000\times 1.025g$ solution contain 2 mole of ethanol

Mass of solvent $=1000\times 1.025-2\times 46$

$m=\frac{2}{1000\times 1.025-2\times 46}\times 1000$

$m=\frac{2}{933}\times 1000=2.143$