[Chemistry Class Notes] on Sulfur Pdf for Exam

Sulfur, also known as sulphur, is amongst the most reactive elements that are present in the periodic table. It is essentially a non-metal which belongs to group 16 (VI A) of the periodic table. The atomic number of sulphur is 16 and it is denoted by S. The element sulphur is a crystalline solid having a bright yellow colour at room temperature. Sulphur is found abundantly in the universe. The sulphur has been used by people since the earlier days and it was known as brimstone which basically means burning stone. 

Sulphur Element

The above image shows the detailed electronic configuration chart of sulphur.

Natural Occurrence of Sulphur

Sulfur or sulphur is the tenth common element of this universe. The creation of 32S takes place in the massive stars where the temperature is more than 2.5 X 109K. It is also present in many types of meteorites in the form of sulphide. The Jupiter moon lo has distinctive colours due to the presence of a sulphur element in several ways in a molten, gaseous and solid-state. On Earth, sulphur is the fifth common element by mass.

Elemental sulphur is generally obtained near the volcanic regions as well as hot springs. In previous times, the primary source of sulphur was Sicily. The submarine volcanoes also lead to the formation of lakes of molten sulphur that is mostly present on the seafloor.

The action of anaerobic bacteria on sulphate minerals like gypsum also leads to the synthesis of native sulphur. Earlier, the commercial production took place by the fossil-based sulphur deposits from gypsum in salt domes. However, this process is currently not the primary source to obtain sulphur for commercial use. Many valuable metal ores like galena, blende, and gypsum are the compounds of sulphur. It is present in the ores in the form of sulphides or sulphates. Natural gas, petroleum and coal also contain sulphur compounds.

Physical Properties of Sulphur

Sulphur is responsible for forming numerous polyatomic molecules. The octa-sulphur is one of the most popular types of molecules associated with sulphur. It is odourless with bright yellow colour and it exists in a soft solid state. The melting point of the molecule is around 115.21° C and its boiling point is about 444.6° C. When the molecule is present between the boiling and melting temperatures, it polymerizes and this leads to lower density but higher viscosity.  The depolymerization happens at higher temperatures, which leads to decreased viscosity. The density of sulphur is approximately 2g/cm³, and it might be higher or lower based on allotrope. 

Chemical Properties of Sulphur

The burning of sulphur produces a blue flame and an irritating odour due to the formation of sulphur dioxide. Sulphur is insoluble in water but partially soluble in non-polar organic solvents, including benzene. The first ionisation energy of this element is 999.6KJ/mol, and the second is 2252 KJ/mol. The most common oxidation states of this element are +4 and +6. Sulphur is highly reactive and almost reacts with all elements even with the iridium (unreactive metal) except noble gases.

Sulphur compounds have many unusual features as they can exhibit catenation similar to carbon. These properties of sulphur allow it to form chain structures as well as a ring system like the carbon. Hydrogen sulphide (H2S) is one of the most familiar compounds of sulphur. It is a colourless and poisonous gas that has the odour of rotten eggs. It is naturally present in the form of vapours in mineral water and volcanoes. During the removal of sulphur from petroleum, a large amount of hydrogen sulphide is obtained.

Oxygen and sulphur also combine to form various compounds. The most known oxide of sulphur is sulphur dioxide which is a poisonous and colourless gas. It is also used as a reducing agent and bleach in several industries. Scientists also used it to obtain sulphur trioxide. This oxide is also beneficial in fruit ripening and food preservation.

Uses of Sulphur

There are several uses of sulphur. Some of the popular ones are as follows:

• Sulphur is an essential element for producing other essential chemicals. The most important chemical produced by sulphur is sulphuric acid which has many industrial applications.

• The reaction of sulphur with methane gives carbon disulfide, which is essential for manufacturing rayon and cellophane.

• Vulcanization of rubber is another important use of the sulphur element.

• Sulphur is one of the crucial components of fertilisers. It is mostly present in fertilisers in the form of a mineral calcium sulphate.

• Many pharmaceutical products contain organosulfur compounds. It is also a component in many agrochemicals and dyestuff.

• People are using elemental sulphur as pesticides and fungicides from previous times. Dusting sulphur (sulphur in powdered form) is a common pesticide in organic farming.