Question

4) Estimate the ethylene glycol C2H6O2 mass in gram that should be added to 12.0 L of water to produce a solution for use in a car’s radiator as antifreeze that freezes at -23.3oC. Assume the density of water to be 1.00 g/mL and Kf = 1.86oC .kg/mol.

Answer 1

Answer on Question #56900 - Chemistry - General Chemistry

Question:

Estimate the ethylene glycol $C_2H_6O_2$ mass in gram that should be added to 12.0 L of water to produce a solution for use in a car's radiator as antifreeze that freezes at -23.3°C. Assume the density of water to be 1.00 g/mL and $K_f = 1.86^{\circ}\mathrm{C} \cdot \mathrm{kg/mol}$.

Answer:

$$\Delta T_f = K_f M$$ $$\Delta T_f = 0^{\circ} \mathrm{C} - (-23.3^{\circ} \mathrm{C}) = 23.3^{\circ} \mathrm{C}$$ $$M = \Delta T_f / K_f = 23.3^{\circ} \mathrm{C} / 1.86^{\circ} \mathrm{C} \ \mathrm{kg/mol} = 15.5269 \ \mathrm{mol/kg}$$ $$m_{\mathrm{EG}} = M \cdot m_{\mathrm{H_2O}} = 15.5269 \ \mathrm{mol/kg} \cdot 12.0 \ \mathrm{kg} = 150.3226 \ \mathrm{mol}$$ $$m_{\mathrm{EG}} = m_{\mathrm{EG}} \cdot M W_{\mathrm{EG}} = 150.3226 \ \mathrm{mol} \cdot 62.07 \ \mathrm{g/mol} = 9330 \ \mathrm{g}$$

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