Connecticut Road Salt & Freezing Point Depression

During Connecticut winters, the Department of Transportation uses various strategies to keep roads clear of ice. They spread sand for traction, but also use chemical de-icers like rock salt (NaCl), calcium chloride (CaCl₂), and even beet juice! This simulation explores the phenomenon of Freezing Point Depression, a colligative property that depends on the number of solute particles in a solution, interfering with water's ability to form strong intermolecular hydrogen bonds and crystallize into ice.

NGSS HS-PS1-3: Plan and conduct an investigation to gather evidence to compare the structure of substances at the bulk scale to infer the strength of electrical forces between particles. (In this simulation, we infer how the bulk property of freezing point is affected by solute particles disrupting the electrical forces (hydrogen bonds) between water molecules).

Treatment Controls

Road Treatment (Solute)

Concentration (Molality, m): 0.0 m

Calculated Properties:

Van 't Hoff Factor (i): 1

Freezing Point: 0.0 °C

Macroscopic Road View

Temp: 5.0°C

Ice Forming!

Microscopic Particle View

Cooling Curve

Data Table

Solute	Concentration (m)	van 't Hoff (i)	Freezing Pt (°C)