Question

Winter is coming and it's time to make sure you have the right amount of antifreeze

in your car. 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 with 6.00 L of
ethylene glycol (antifreeze).
What is the molality of that solution?
The chemical formula for ethylene glycol is C2H602 and its density is 1.1132 g/cm3. (
Hint- use the density to find the mass of 6.0 L of C2H6O2, and remember that 1.0cm3
= 1.0 mL and that 1.0 L of water = 1.0 kg)

Answer 1

The molality of the solution = 17.93 m

Further explanation

Given

6.00 L water with 6.00 L of ethylene glycol(ρ=1.1132 g/cm³= 1.1132 kg/L)

Required

The molality

Solution

molality = mol of solute/ 1 kg solvent

mol of solute = mol of ethylene glycol

• mass of ethylene glycol :

= volume x density

= 6 L x 1.1132 kg/L

= 6.6792 kg

= 6679.2 g

• mol of ethylene glycol (MW=62.07 g/mol)

=mass : MW

=6679.2 : 62.07

=107.608

• mass of water

6 L water = 6 kg water(ρ= 1 kg/L)

• molality

`\tt =(107.608)/(6)=17.93~m`