S.3 Chem. Notes Caltec S.3

υ CALTEC ACADEMY MAKERERE S 3 CHEMISTRY PACKAGE (SSALONGO ’S WORK) SULPHU R AND ITS COMPOU NDS Sulphur s a non‐ metal with atomic number 16, position 16, group VI and period 3 in the periodic table. Occurrence; Occu rs natu rally as free Sulphur underground, as hydrogen sulphide in petroleum and in ores of metals as metal sulphides. Extraction of Sulphur • Is carried out by the Frasch process • A hole is dung in the underground to reach the Sulphur bed. • A Sulphur pump, consisting of three concent ric tubes /pipes is sunk into the hole up to the Sulphur bed. • In the outer most pipe, supe r‐ heated water under pressu re is forced down to the Sulphur bed to melt the Sulphur. • Hot comp ressed air under pressure is sent down the Sulphur bed through the innermost pipe. • This pushes the molten Sulph ur and water up through the middle pipe. • Sulphur is then collected and water is evaporated off. Diag ram of Sulphur pump showing how it is used to extract Sulphur. (resea rch and draw) Allotropes of Sulphur Allotropes are different forms of the same element existing in the same physical state. Sulphur has up to 5 allotropes Crystalline allotropes Non‐crystalline Rhombic Sulphur (alpha) Amorphous Sulphur Monoclinic Sulphur (beta) Plastic Sulphur Colloidal Sulphur The most important allotropes are Rhombic Sulphur and monocli nic Sulphu r. Rhombic Sulphur is only stable below 96. Above this tempe rature, it slowly changes to monocl inic Sulphur. Monoclinic Sulphur is only exists above 96. 96 is called the transition tempe rature of Sulphur. Structure of Rhombic Sulphur (research & draw ) Structure of monoclinic Sulphur (resea rch & draw) LESS ON 2 Differences between rhombic and monoclinic Sulphur Rhombic Sulphur Monoclinic Sulphur • …