Laboratory Operations - Distillation, gravity filtration and vacuum filtration

What is distillation

it is the process of vaporizing a liquid mixture in a round bottom flask and condensing the vapor through a condenser then collecting the vapors in a graduate cylinder

What is the distilland

it is the liquid mixture that is heated in a round bottom flask using a heating mantle

What do the vapors from the pot (the round bottom flask) travel through

they travel through the water-cooled condenser

What happens to the vapors upon contact

they condense and travel to the receiver (usually a graduated cylinder)

What happens if there is more than one liquid component in the distilland

then the component that is most volatile will be in the receiving flask first and the lesser volatile component will be in the pot

what will the vapor above the liquid contain compared to the liquid in the pot

it will always contain the lower boiling components than the liquid in the pot

How full should the RBF be

it should never be more than half full

What should the RBF always contain

it should contain boiling chips to prevent bumping

What is the thermometer in distillation used for

it is used to monitor the boiling point of vapors, which is why it is essential to know the boiling point of dichloromethane

Where is the thermometer

it is installed in the distillation head and the bulb should be centered in the stilled and the bulb directly below the side arm connection

What does the placement of the thermometer ensure

it ensures that the thermometer is immersed in vapors to obtain an accurate boiling point, thermometers too high or low can result in incorrect temperature reading

What is the purpose of gravity filtration

its purpose is to remove a solid from a liquid components

When is gravity filtration normally conducted

it is normally conducted during recrystallization to remove impurities, activated carbon, or a drying agent from dried organic liquids

what are examples of a drying agent

magnesium sulfate or sodium sulfate

How is gravity filtration conducted

it is conducted through the use of a funnel containing filter paper

What is the typical flask used for gravity filtration

it is normally an Erlenmeyer flask

what is the liquid collected fro gravity filtration called

it is called the filtrate

where is the funnel for gravity filtration placed

it is placed in a ring support positioned directly over the collecting flask

What is the temperature of the solvent when conducting recrystallization with gravity filtration

they solvent is hot, and in order to prevent the crystals from crystallizing in the funnel, the funnel is heated. this is known as hot gravity filtration

What is vacuum filtration

it is a common technique in organic chemistry to isolate a solid from a solid/liquid mixture or in removing impurities from a large quantity of liquid

what is another name for vacuum filtration

it is also known as suction filtration

What is the set up of vacuum filtration

a porcelain Buchner funnel is placed on a vacuum filter flask which is connected via thick vacuum tubing to the inlet of a vacuum aspirator

What is placed in the Buchner funnel

a circular piece of filter paper

What is the filter paper moistened with

it is moistened with an appropriate ice-cold solvent (generally whatever liquid the crystals are currently in)

What does the vacuum aspirator do

it forces the liquid through the filter paper to collect into the filter flask

what happens to the solid once it is put on the filter paper

it will be air dried for several minutes