PCQA111 Week 11 Group IVA and IVB PDF

UNIT OUTCOMES At the end of this unit, the students are expected to: Demonstrate a comprehensive understanding of the chemistry of metals, non-metals and metalloids. UNIT OUTLINE ✔ Elements ✔ Properties ✔ Identification Tests ✔ Compounds and Their Uses CHECKLIST Read the availa...

UNIT OUTCOMES At the end of this unit, the students are expected to: Demonstrate a comprehensive understanding of the chemistry of metals, non-metals and metalloids. UNIT OUTLINE ✔ Elements ✔ Properties ✔ Identification Tests ✔ Compounds and Their Uses CHECKLIST Read the available learning references before the discussion. Search for the meaning of the following terminologies. Listen and participate in the board discussion. GROUP IV A THE CARBON FAMILY C, Si, Ge, Sn, Pb CARBON abundant nonmetallic, tetravalent element, has several allotropic forms. CARBON exhibits remarkable properties, some paradoxical different forms include the hardest naturally occurring substance (diamond) and one of the softest substances (graphite) known. CARBON has great affinity for bonding with other small atoms, including other carbon atoms, and capable of forming multiple stable covalent bonds with such atoms. CARBON the greatest importance attaches to its function as the basic building unit of organic compounds. CARBON It also occurs in compounds such as carbonates, oxalates, tartrates and acetates. CARBON used as a reducing agent in the preparation of many metals relatively inert at room temperature At elevated temperature, it combines directly with OXYGEN, HALOGENS and most other NON-METALS CARBON ALLOTROPES DIAMOND GRAPHITE LONSDALEITE C60 (Buckminsterfullerene) C70 C540 Activated Charcoal Component of universal antidote Adsorbent Used in Diarrhea and in poisoning Carbon dioxide (CO2) Carbonic acid gas Respiratory stimulant (CO poisoning) Treatment of persistent hiccups Used in the manufacturing of soda, carbonated water Dry ice  Refrigerants  Solid CO2  Acne, corns, calluses, moles, warts and eczema Carbon monoxide (CO) Cherry red color of blood 210X affinity to hemoglobin Automobile exhaust ANTIDOTE: oxygen(100%) artificial air hyperbaric O2 O2-CO2 mixture SILICON A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. Silicon powder as coarse powder with a dark gray color with bluish tinge. Silicon carbide Silica gels Silicon dioxide Silica Abundant in nature Poisoning: Silicosis (hemoptysis) ANTIDOTE: Alumina (Al2O3)  Glass Formed by fusion of Silicon with base agents used to modify glass. (Na2CO3 with pure silica) Modified by addition of: 1. B - ↓coefficient of expansion 2. Pb - ↓refractive index 3. K - amber color, light resistant properly 4. MnO2 - mask color of Fe2O3  Types of Glass Type I Highly resistant borosilicate glass Type II Treated soda lime glass Type III Soda lime Type IV General soda lime glass, NP  Purified Silicaceous Earth SiO2 “KIESELGUHR silica” Adsorbent Filtering aid Clarifying agent  Attapulgite (Polymagma, Quintess) Magnesium Aluminum Phyllosilicate (Mg,Al)2Si4O10(OH)·4(H2O) Anti-diarrheal agent Natural Calamine Zn silicate Simethicone Antiflatulent GERMANIUM a lustrous, hard, silver-white metalloid that is chemically similar to tin forms a large number of organometallic compounds and is an important semiconductor material used in transistors GERMANIUM is a rare element and occurs in minute quantities in many metal sulfides. TIN occurs chiefly as the oxide, SnO2 (AMPHOTERIC) silvery, malleable poor metal that is not easily oxidized in air and resists corrosion is found in many alloys and is used to coat other metals to prevent corrosion. TIN Tin is obtained chiefly from the mineral cassiterite, where it occurs as an oxide. It is the classic alloying metal to make bronze. Cassiterite Tin Sn+2 Sn+3 USES: Manufacture of cans Household utensils  Tin fluoride (SnF2) Anti-cariogenic 8%- 1 application Tin oxide (SnO2) Germicidal aganist Staphylococcus aureus.  Tin alloys Gun metal (10% tin and 90% copper) Plumbers Alloy (33% lead and 66% tin), Pewter Metal (75% tin and 25% lead), Type Metal (75% lead, 5% tin, and 20% antimony), Bearing Metal (82% tin,14% antimony, and 4% copper Phosphor Tin (made by adding phosphorus to molten tin) in Phosphor-Bronze LEAD occurs mainly as the sulfide PbS, called “galena”. soft, heavy, toxic and malleable poor metal, lead is bluish white when freshly cut but tarnishes to dull gray when exposed to air. LEAD LEAD Lead is used in building construction, lead-acid batteries, bullets and shot, and is part of solder, pewter, and fusible alloys. LEAD Lead has the highest atomic number of all stable elements - although the next element, Bismuth, has a half life so long (longer than the estimated age of the universe) it can be considered stable. LEAD Like mercury, another heavy metal, lead is a potent neurotoxin which accumulates in soft tissues and bone over time. Lead Pb+2 Pb+4 USES: Astringent Protein precipitant  PLUMBISM Lead Encepalopathy Characterized by memory loss, irritability, projectile vomiting ANTIDOTE: EDTA Calcium Sodium Versenate Sources of Lead: Lead pipe Cocktail glass Canned food Automobile exhaust Paints Earthen utensils Cable wires  Lead acetate Pb(CH3COO) 2 “Sugar of Lead” “Salt of Saturn” Astringent Pharmaceutical necessity for preparation of Lead Subacetate solution Pb2O(CH3COO)2 “Goulard’s Extract” Solution of lead acetate and lead oxide Astringent, antiseptic  Lead oxide “Litharge” Preparation for Lead Subacetate Pewter Metal 80% tin and 20% lead Rose Metal 25% tin, 25% lead, and 50% bismuth Solder Metal 50% tin and 50% lead Ge, Sn, Pb are active metals they will displace hydrogen gas from acids and combine with most non-metals CHEMICAL PROPERTIES Pb and Sn may give up their two unpaired p electrons to form Pb2+ and Sn2+. in the 4+ oxidation  covalent bond character stability of 2+ ↑ as atomic weight ↑ stability of 4+ ↓ as atomic weight ↑ OXIDES AND HYDROXIDES: Sn and Pb  amphoteric SnO/ Sn(OH)2 + BASE  stannite ion (SnO22-) PbO/ Pb(OH)2 + BASE  plumbite (PbO22-) In the +4 oxidation state… SnO2 + BASE  stannate (SnO32-) PbO2 + BASE  plumbate (PbO32-) IDENTIFICATION TESTS OF IONS Pb2+ 1) K2CrO4: yellow ppt of PbCrO4 soluble in NaOH 2) HCl: white ppt of PbCl2 soluble in boiling or hot water  IDENTIFICATION TESTS OF IONS Sn2+ Sn4+ 1) H2S Brown ppt of SnS Yellow ppt of SnS2 2) HgCl2 White ppt of No reaction Hg2Cl2 turning gray IDENTIFICATION TESTS OF IONS Carbon CH3COO- (C2H3O2-, Ac-, Oac-)  Acids will evolve CH3COOH (vinegar-like odor) CH3COOH heated with C2H5OH  fruity odor, C2H5C2H3O2(ethyl acetate) IDENTIFICATION TESTS OF IONS Carbon CO32- and HCO3- 1) Acids will evolve CO2 manifested by effervescence (bubbling of gas through the liquid) 2) Phenolphthalein : dark pink or red for CO32-; colorless or light pink for HCO3- IDENTIFICATION TESTS OF IONS Carbon C2O4- C4H4O6- C6H5O7- (oxalates) (tartrates) (citrates) 1) CaCl2 CaC2O4 Ca C4H4O6 Ca3C6H5O7 white ppt white ppt On boiling a) HAc insoluble soluble Soluble 2) AgNO3 (-) Ag mirror on Ag mirror on (ammoniacal) warming boiling 3) pyridine & (-) Emerald green Carmine red acetic anhydride solution solution GROUP IV B TITANIUM SUBGROUP Ti, Zr, Hf Titanium “Titans-Sons of Earth” Powerful reducing agent The principal ore are: Rutile, TiO2 (tetrahedral structure), Brookite, TiO2 (orthorhombic structure), Anatase, TiO2 (orthorhombic structure), Ilmenite, FeTiO3, and Sphene or Titanite, CaO.SiO2.TiO2 Titanium Titanium dioxide is used as a pigment since it has good covering power and is quite inert. IDENTIFICATION TEST: H202 (acidic sol’n): red color  Compounds with oxidation states of 2+ (good reducing agents), 3+ and 4+ (most common). It is difficult to prepare the pure metal due to its affinity for carbon, nitrogen, oxygen and hydrogen.  Titanium dioxide Solar ray protectant Lotions & sunblocking creams Opacifying agent MOA: reflects UV rays Protective – PABA MOA: absorbs UV rays Zirconium Used as deodorant & antiperspirant Causes pulmonary granuloma formation Can lead to cancer The principal ores are: Zircon, ZrSiO4, and Baddeleyite, ZrO. REFERENCES Qualitative Analysis by Esmarch S. Gilreath Remington: The Science and Practice of Pharmacy 21st Edition