Question

calculate the molality of ethanol in a solution that which contains 55 g of ethanol in 0.42 kg of water . the molar mass of ethanol is 46 g/mol

Answer 1

Answer on Question #83590 – Chemistry – Other

Task:

Calculate the molality of ethanol in a solution that which contains 55 g of ethanol in 0.42 kg of water. The molar mass of ethanol is 46 g/mol.

Solution:

$$Molality(m) = \frac{Moles\ of\ Solute}{Ki\ log\ rams\ of\ Solvent}$$ $$Moles\ of\ Solute = n(ethanol) = \frac{m(ethanol)}{M(ethanol)};$$ $$Moles\ of\ Solute = \frac{55g}{46\ g/mol} = 1.19565\ moles\ of\ ethanol.$$ $$Ki\ log\ rams\ of\ Solvent = m(H_2O) = 0.42\ kg.$$

Then,

$$Molality(m) = \frac{1.19565\ mol}{0.42\ kg} = 2.8468\ mol/kg$$

Answer: The molality of ethanol in a solution = 2.8468 mol/kg.

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