If you want to lower water's freezing point 18 degrees C by adding NaCl, what must the molality of the salt solution be? (K(f) for water ris 1.86 degree C/m)

4.84 m

Explanation:

To solve this problem we need Frezing point depression.

Formula is: ΔT = Kf . m . i

ΔT = 18°C

This is data. ΔT is the difference, Freezing T° of pure solute - Freezing T° of solution.

Kf = 1.86 °C/m

m = molality. Our unknown.

i = Ions dissolved in solution, also called Van't Hoff factor.

NaCl → Na⁻  +  Cl⁻

Sodium chloride can produce 2 moles of ions.

We replace data: 18°C = 1.86 °C/m  .  m   .  2

18°C / (1.86 °C/m) . 2 = m

molality = 4.84

hope this

explanation:

covalent bonds

consist of pairs of electrons shared by two atoms, and bind the atoms to fixed orientation and requre high energies to break them

ionic bonds

when two atoms differ considerably in their electronegativity, then one of the atoms will lose its electron to the other atom. this results in a positively charged ion(cation) and a negatively charged ion (anion)