THE CHEMICAL EARTH: 1. The living and nonliving components of the Earth contain mixtures ● Construct word and balanced formulae equations of chemical reactions as they are encountered Reactants → products Chemical reaction: the way atoms are joined changes‚ atoms are not created nor destroyed‚ but are rearranged Indicators: emission of light or heat‚ odour formation of a gas formation of a precipitate colour change change in state aqueous = dissolved in water‚ an aqueous solution
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is a rapid and accurate technique in which electrolysis of experimental solution is carried out by using one electrode of comparatively large surface area (i.e. non-polarisable electrode) and the other electrode having a very small area (polarisable electrode). The non polarisable electrode is SCE used as reference electrode. Alternatively Hg pool can be used where the polarisable electrode consist of dropping mercury electrode (DME) During electrolysis potential difference is applied to the cell
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AP* Chemistry ELECTROCHEMISTRY Terms to Know: Electrochemistry—the study of the interchange of chemical and electrical energy OIL RIG – oxidation is loss‚ reduction is gain (of electrons) Oxidation – the loss of electrons‚ increase in charge Reduction – the gain of electrons‚ reduction of charge Oxidation number – the assigned charge on an atom Oxidizing agent (OA) – the species that is reduced and thus causes oxidation Reducing agent (RA) – the species that is oxidized and thus causes reduction
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these factors affect the calculated values for Ecell. INTRODUCTION Electrochemistry is the branch of chemistry that deals with the relationship of electricity and chemical reactions. Batteries‚ control of corrosion‚ metallurgy and electrolysis are some of the many applications of electrochemistry in everyday life. Electrochemistry always involves an oxidation-reduction process‚ wherein electrons are transferred from one substance to the other. This reaction is thermodynamically spontaneous
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CHM 096 TUTORIAL 6 Mar 2013 (ELECTROCHEMISTRY) 1. Determine the oxidation number of the first name element in the following ions. a) Cr2O72 d) AsO33 b) SbF6 e) BaH2 c) MoO42 f) ClO4− 2. Determine whether each of the reactants shown in the following half-reactions is being oxidized or reduced. a) As4+ As3+ b) Cl2O7 HClO4 c) C2H4O C2H6O d) SO2 SO42− e) Cr2O72− Cr3+ 3. Indicate whether each of the following is or
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imports from France and Germany so America had to start manufacturing the metal. There are two processes used to make calcium. The first process is electrolysis of fused calcium chloride or calcium fluoride. The calcium is melted in an electrically heated graphite container and there is a water-cooled iron bar just below the surface. During electrolysis‚ calcium is put on the iron cathode and a metal stick known as a carrot is formed. The carrots are then remelted or are vacuum-distilled to purify
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Pure aluminium is a relatively soft‚ silvery white metal. When exposed to air‚ a thin coating of Aluminium oxide gives it a dull lustre. It is three times less dense than water‚ and has great strength when alloyed‚ it doesnt rust and has high electrical conductivity‚ and Aluminium is also ductile‚ making it a very useful metal. Aluminium readily makes alloys with copper‚ zinc‚ magnesium‚ manganese and silicon. Aluminium foil is 92-99% pure aluminium. Other uses of aluminium alloys include computers
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Identification and Production of Materials ================================ Ethene‚ Polymers and Ethanol ================================ Catalytic Cracking Oil refineries need to balance their outputs of various products (petrol‚ diesel‚ fuel oil‚ etc.) to match the demands of the marketplace. Catalytic cracking is the process in which high molecular weight (high boiling point) fractions from crude oil are broken into lower molecular weight (lower boiling point) substances in order to increase
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Pilonidal Cysts A pilonidal cyst is a cystic structure that develops along the tailbone near the cleft of the buttocks‚ approximately 4 cm to 5 cm from the anus. These cysts usually contain hair and skin debris. Individuals with a pilonidal cyst may not have any symptoms at all‚ whereas others may develop an infection of the cyst with associated pain and inflammation. The treatment and management of pilonidal cysts depends on many factors‚ including the extent and chronicity of the disease. Recurrence
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Conversion: sulfur dioxide + oxygen sulfur trioxide 2SO2 (g) + O2 (g) 2SO3 (g) Oleum Absorption: sulfur trioxide + sulfuric acid oleum SO3 (g) + H2SO4 (l) H2S2O7 (l) Oleum Dilution: oleum + water sulfuric acid H2S2O7 (l) + H2O (l) 2H2SO4 (l) ELECTROLYSIS of Sodium Chloride: Molten NaCl: Overall reaction: 2NaCl (l) 2Na (l) + Cl2 (g) Half-equations: 2Cl− (l) Cl2 (g) + 2e− Na+ (l) + e− Na (s) Concentrated NaCl: Half-equations: 2Cl− (aq) Cl2 (g) + 2e− 2H2O (l) + 2e− H2 (g) + 2OH− (aq) Dilute NaCl:
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