A coolant is made by dissolving 93 g of ethylene glycol, C₂H₆O₂, of molar mass 62 g/mol, in 500 g…

Step 1. Moles. $\dfrac{93\ \text{g}}{62\ \text{g/mol}} = 1.5\ \text{mol}$.

Step 2. Molality. $m = \dfrac{1.5\ \text{mol}}{0.500\ \text{kg}} = 3.0\ \text{mol/kg}$.

Step 3. Freezing point. $\Delta T_f = 1.86\ \text{K kg/mol} \times 3.0\ \text{mol/kg} = 5.58\ \text{K}$, so the coolant freezes at $-5.58\ ^\circ\text{C}$.

Step 4. Boiling point. $\Delta T_b = 0.512\ \text{K kg/mol} \times 3.0\ \text{mol/kg} = 1.536\ \text{K}$, so it boils at $101.54\ ^\circ\text{C}$.