Organic Lab
Melting point
1. What two effects do impurities have on the melting point of an organic compound?
Soluble impurities affect the melting point of a solid in the following manner.
a. The presence of an impurity in the molten compound reduces its vapor pressure thus lowering the melting point of the compound.
b. Broaden the melting point range.
2. For what tow purpose are melting points routinely used
a. To determine the identity of an organic solid.
b. To determine the purity of an organic solid.
3. What effects on the measured melting point would you expect in each of the following cases?
a) Presence of pieces of glass in the sample
No effect.
b) Presence of solvent within the crystals
Melting point depression, Melting point range broaden.
c) Using too large sample when determining the melting point
Too much material will broaden range &may increase melting point
Lab Questions
1. Define the following
A. Melting point
B. Intermolecular forces
C. Hydrogen bonding
2. Arrange the following IMF according to there strength
Dipole-Dipole interaction forces, Hydrogen bonding, Van der Waals forces
3. How does the atmospheric pressure affect the melting point?
4. What is the purpose of determining the melting point in this lab?
5. Why is this method not used for finding the melting points of inorganic ionic compounds?
Recrystallization Questions 1. What is the purpose of recrystallization?
It is the primary method of purifying crude solid compounds.
2. What is the recrystallization method based on?
It is a process based on the differences in solubilities of solids in a given solvent system.
3. How can you increase the solubility of a compound?
You can increase it with added heat.
4. How do you get rid of insoluble impurities?
They are removed through the method of hot filteration.
5. How do you separate the purified solid crystals from the
1. What two effects do impurities have on the melting point of an organic compound?
Soluble impurities affect the melting point of a solid in the following manner.
a. The presence of an impurity in the molten compound reduces its vapor pressure thus lowering the melting point of the compound.
b. Broaden the melting point range.
2. For what tow purpose are melting points routinely used
a. To determine the identity of an organic solid.
b. To determine the purity of an organic solid.
3. What effects on the measured melting point would you expect in each of the following cases?
a) Presence of pieces of glass in the sample
No effect.
b) Presence of solvent within the crystals
Melting point depression, Melting point range broaden.
c) Using too large sample when determining the melting point
Too much material will broaden range &may increase melting point
Lab Questions
1. Define the following
A. Melting point
B. Intermolecular forces
C. Hydrogen bonding
2. Arrange the following IMF according to there strength
Dipole-Dipole interaction forces, Hydrogen bonding, Van der Waals forces
3. How does the atmospheric pressure affect the melting point?
4. What is the purpose of determining the melting point in this lab?
5. Why is this method not used for finding the melting points of inorganic ionic compounds?
Recrystallization Questions 1. What is the purpose of recrystallization?
It is the primary method of purifying crude solid compounds.
2. What is the recrystallization method based on?
It is a process based on the differences in solubilities of solids in a given solvent system.
3. How can you increase the solubility of a compound?
You can increase it with added heat.
4. How do you get rid of insoluble impurities?
They are removed through the method of hot filteration.
5. How do you separate the purified solid crystals from the