Lab of volatile liquid
Lab 4 - Molar Mass of a Volatile Liquid
Purpose: To determine the molar mass of an unknown liquid whose boiling point is between room temperature and the boiling point for water.
Key Terms: List and define any additional new terms relevant to this experiment.
volatile –
intermolecular forces -
Key Formulas: Write the following formulas.
Ideal Gas Law Molar Mass
Relationships: The Dumas Method - In 1826 Jean-Baptist Dumas developed a method for determining the molar mass of liquids that can be boiled under laboratory conditions. At that time the concept of the mole was not yet understood so Dumas studied the relative densities of the vapors by using Boyle’s, Charles’ and Avogadro’s Laws.
In this experiment the ideal gas law will be utilized to solve for the number of moles of vapor while other conditions are equilibrated with a boiling water bath. By measuring the mass of that vapor the molar mass can be calculated. A major assumption is that the vapor will behave as an ideal gas, but a vapor near its boiling point behaves least like an ideal gas. Unknowns for this experiment were chosen to maximize ideal behavior.
Pre-Lab Questions:
1. How does the relative strength of the intermolecular forces between gas particles affect the gases deviation from ideal behavior?
2. What type of intermolecular forces would lead to the most ideal behavior?
Procedure:
Set-Up – The apparatus
1. Prepare a hot water bath with a 600 mL beaker and a Bunsen burner.
a. Use a ring stand with two rings. Support the base of the beaker with a ring and wire gauze and another ring to prevent the beaker from falling over.
b. Fill with 200-300 mL of water and 2-3 boiling chips.
2. Obtain a small square of aluminum foil sufficient to cover a 125-mL Erlenmeyer flask. Secure the foil over the flask with a rubber band. Puncture the foil with a pin to create a small hole.
3. Record the mass of your dry flask/foil/rubber band.
4. Draw a
Purpose: To determine the molar mass of an unknown liquid whose boiling point is between room temperature and the boiling point for water.
Key Terms: List and define any additional new terms relevant to this experiment.
volatile –
intermolecular forces -
Key Formulas: Write the following formulas.
Ideal Gas Law Molar Mass
Relationships: The Dumas Method - In 1826 Jean-Baptist Dumas developed a method for determining the molar mass of liquids that can be boiled under laboratory conditions. At that time the concept of the mole was not yet understood so Dumas studied the relative densities of the vapors by using Boyle’s, Charles’ and Avogadro’s Laws.
In this experiment the ideal gas law will be utilized to solve for the number of moles of vapor while other conditions are equilibrated with a boiling water bath. By measuring the mass of that vapor the molar mass can be calculated. A major assumption is that the vapor will behave as an ideal gas, but a vapor near its boiling point behaves least like an ideal gas. Unknowns for this experiment were chosen to maximize ideal behavior.
Pre-Lab Questions:
1. How does the relative strength of the intermolecular forces between gas particles affect the gases deviation from ideal behavior?
2. What type of intermolecular forces would lead to the most ideal behavior?
Procedure:
Set-Up – The apparatus
1. Prepare a hot water bath with a 600 mL beaker and a Bunsen burner.
a. Use a ring stand with two rings. Support the base of the beaker with a ring and wire gauze and another ring to prevent the beaker from falling over.
b. Fill with 200-300 mL of water and 2-3 boiling chips.
2. Obtain a small square of aluminum foil sufficient to cover a 125-mL Erlenmeyer flask. Secure the foil over the flask with a rubber band. Puncture the foil with a pin to create a small hole.
3. Record the mass of your dry flask/foil/rubber band.
4. Draw a