Chemistry: How many moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C? The freezing point depression constant for water is 1.86°C•kg/mol. What is the molality of the solution?

How many moles of ethylene glycol must be added

Kate1678

29.01.2022

1.29 moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C. Molality of solution is 1.29 m.

Explanation:

Depression in freezing point is given by:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=T_f^0-T_f=(0-(-2.4))^0C=2.4^0C$ = Depression in freezing point

i= vant hoff factor (for non electrolyte , i = 1)

K_f = freezing point constant for water= 1.86^0C/kgmol

m= molality = $\frac{\text{moles of solute}}{\text{weight of solvent in kg}}$

m= molality = $\frac{x}{1kg}$

$2.4^0C=1\times 1.86^0C/kgmol\times \frac{x}{1kg}$

x=1.29

Molality = $\frac{\text{moles of solute}}{\text {weight of solvent in kg}}=\frac{1.29mol}{1kg}=1.29m$

Thus 1.29 moles of ethylene glycol must be added to 1 kg of water to make a solution with a freezing point of -2.4°C. Molality of solution is 1.29 m.

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hayleyl05

17.09.2020

group 5

Explanation:

the element with 15 protons is phosphorus. phosphorus is in the 5th group on the periodic table of elements

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