# What is the freezing-point depression of naphthalene?

Page Contents

- 1 What is the freezing-point depression of naphthalene?
- 2 How is freezing-point depression related to molar?
- 3 How do you find the freezing point of naphthalene?
- 4 What is the method to determine molecular weight by depression of freezing point method?
- 5 How do you determine the melting and freezing point of naphthalene?
- 6 How do you calculate freezing point depression?
- 7 How does freezing point depression affect molecular weight?

## What is the freezing-point depression of naphthalene?

6.90 oC/m.

The freezing-point depression constant for naphthalene is 6.90 oC/m.

Thus, as the molar mass increases, the freezing point depression decreases. That is, increasing the molar (or molecular) mass will have a smaller effect on the freezing point.

## How do you find the freezing point of naphthalene?

Ignite the Bunsen burner and using direct heat melt the naphthalene powder until it completely turns to a liquid. When the temperature reaches approximately 90o Celsius, stop heating. 6. Observe the change in temperature from 90o to 70o Celsius, recording the temperature at regular intervals, preferably 15 seconds.

## What is the method to determine molecular weight by depression of freezing point method?

Review the calculation of the molality (not molarity) of a solution: Molality = (mol solute)/(1000 g solvent) Page 3 Review the equation for the freezing-point depression, ∆t = Kf•m, where Kf is the molal freezing-point depression constant of the solvent (given) and m is the molality of the solution.

## How do you determine the melting and freezing point of naphthalene?

Hold a thermometer with its bulb in the naphthalene. Use a small flame to heat the test-tube gently and watch the thermometer reading. To find the melting range, note the temperature when the naphthalene melts. Leave to cool and note the temperature when the naphthalene solidifies.

## How do you calculate freezing point depression?

The freezing point depression ∆T = KF·m where KF is the molal freezing point depression constant and m is the molality of the solute. Rearrangement gives: mol solute = (m) x (kg solvent) where kg of solvent is the mass of the solvent (lauric acid) in the mixture.

## How does freezing point depression affect molecular weight?

So, by increasing the value of depression in freezing point, the molecular weight decreases and vice versa. Thus, an increase in the molecular weight will have a smaller effect on the freezing point.