The best mixture of antifreeze and water is 50% antifreeze with 50% water. the cooling system in your car has a mixture of 6.00 l water and 6.00 l ethylene glycol (antifreeze). the molality of the solution is 17.9m. the chemical formula of ethylene glycol (antifreeze) is c2h6o2 and its density is 1.1132 g/cm3.

at what temperature would this mixture freeze?

-43.3°c

-20°c

-89.0°c

-73.3°c

-33.3°c

ΔTf = - 33.3 °C

Explanation:

∴ Kf H2O = 1.86 K.Kg/mol

∴ m = 17.9 mol/Kg

solute: C2H6O2

solvent: H2O

mix C2H6O2/H2O

⇒ ΔTf = - (1.86 °C.Kg/mol)×(17.9 mol/Kg)

⇒ ΔTf = - 33.294 °C ≅ - 33.3 °C

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%