N12/4/CHEMI/SPM/ENG/TZ0/XX 88126104 CHEMISTRY standard level Paper 1 Friday 9 November 2012 (afternoon) 45 minutes INSTRUCTIONS TO CANDIDATES • Do not open this examination paper until instructed to do so. • Answer all the questions. • For each question‚ choose the answer you consider to be the best and indicate your choice on the answer sheet provided. • The periodic table is provided for reference on page 2 of this examination paper. • The maximum mark for this examination
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carbonate is domestically well known for its everyday use as a water softener. It is also used to remove grease‚ oil and wine stains. It can be extracted from the ashes of many plants. It is synthetically produced in large quantities from salt (sodium chloride) and limestone in a process known as the Solvay process. Titration is also known as titrimetry. It is the process‚ operation‚ or method of determining the concentration of a substance in a solution by adding a standard reagent of known concentration
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and would take a long time to dry. A drying procedure is therefore necessary to remove all traces of water before the solvent is evaporated. This procedure consists of two steps: (1) thoroughly mixing the solution with saturated aqueous sodium chloride (saturated salt solution) and discarding the aqueous layer (this is a preliminary drying step that removes most of the water) and (2)‚ adding a solid inorganic drying agent (this strongly binds to the remaining traces of water dissolved in the
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Dissolve solid KA1 in distilled water and filter. Use separate portions of the filtrate for the following tests. (i) Add aqueous sodium hydroxide‚ then in excess. (ii) Add aqueous ammonia‚ then in excess followed by aqueous ammonium chloride. (iii) Add aqueous iron (III) chloride‚ then warm. (iv) Add aqueous silver nitrate‚ followed by dilute nitric acid. (v) Add aqueous disodium hydrogen phosphate. (vi) Add aqueous potassium chromate (VI) followed by dilute hydrochloric acid. Observation Solutions smells
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State the chemical phenomenon responsible for these coatings and also write chemical names of each coating. How is our brain double-protected against injuries and shocks? Identify the type of chemical reactions in the following processes: a) Barium chloride solution is mixed with copper sulphate solution and a write precipitate is formed. b) On heating copper powder in a china dish‚ the surface of copper powder become black. c) On heating green ferrous sulphate crystals‚ reddish brown solid is left
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The Preparation of 1- Bromobutane Introduction... Aim : To prepare 1-Bromobutane. Background : The most common way of preparing alkyl halides‚ which are very useful intermediates in syntheses‚ is the replacement of the OH group of an alcohol by a halogen. This replacement is a nucleophilic substitution reaction‚ and alcohols do not undergo nucleophilic substitution reactions because hydroxide ison is strongly basic and a poor leaving group. However‚ alcohols readily undergo
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Chapter 7 Matching Match each item with the correct statement below. a. halide ion e. valence electron b. octet rule f. coordination number c. ionic bond g. metallic bond d. electron dot structure ____ 1. an electron in the highest occupied energy level of an atom ____ 2. Atoms react so as to acquire the stable electron structure of a noble gas. ____ 3. a depiction of valence electrons around the symbol of an element ____ 4. an anion of chlorine or other halogen ____ 5. the force of attraction
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List the formula for determining percent composition by mass. Objectives: 1. to separate a three component mixture and 2. determine the percent composition by mass of each component in the mixture. Materials: Ammonium chloride (NH4Cl)‚ Sodium chloride (NaCl also known as table salt)‚ and Silicon dioxide (SiO2 also known as sand) Equipment: a variety of equipment is available at the supply table Procedure: Week One‚ Day 1: Make your mixture and separate it. 1. Mass
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volume is added to a known volume of a second solution until the reaction between them is complete. The objective of this experiment is reacting sodium bicarbonate (NaHCO3) and sodium carbonate (NaCO3) with hydrochloric acid (HCl) to produce sodium chloride (NaCl)‚ water (H20) and carbon dioxide (CO2). -Use the titrations of the following chemical reactions: NaHCO3 + HCl (aq) NaCl (aq) + H2O (l) + CO2 (g) 2HCl (aq) + Na2CO3 (s) 2NaCl (aq) + H2O (l) + CO2 (g) Experimental procedure- Two Erlenmeyer
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THE INTRODUCTION TO SOAP MANUFACTURE BY W. H. SIMMONS‚ B.Sc. (Lond.)‚ F.C.S. AND H. A. APPLETON It has been said that the use of soap is a gauge of the civilisation of a nation‚ but though this may perhaps be in a great measure correct at the present day‚ the use of soap has not always been co-existent with civilisation‚ for according to Pliny (Nat. Hist.‚ xxviii.‚ 12‚ 51) soap was first introduced into Rome from Germany‚ having been discovered by the Gauls‚ who used the product obtained
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