EJC 2024 H2 Chemistry Practical Planning Handbook

EJC Chemistry Practical Planning Handbook H2 Chemistry / 9729 Eunoia Junior College Page 1 Contents OVERVIEW ................................ ................................ ..................... 2 TYPE OF PLANNING ................................ ................................ ........ 2 WRITING A PLAN ................................ ................................ ............ 2 1. DEFINING THE PROBLEM ................................ ............................. 5 1.1. For a quantitative exercise ................................ ................. 5 1.2. For a qualitative exercise ................................ ................... 5 2. METHOD ................................ ................................ .................... 5 3. PLANNING ANALYSIS, CONCLUSIONS AND EVALUATION ................ 5 3.1. Analysing Data ................................ ................................ .. 5 3.1.1. Calculations ................................ ............................. 5 3.1.2. Error analysis ................................ .......................... 5 3.2. Evaluation................................ ................................ .......... 6 3.3. Drawing Conclusions ................................ ......................... 6 BASIC LABORATORY PROCEDURES ................................ ................. 6 A. Balances and Weighing ................................ ..................... 6 B. Working with Liquids ................................ .......................... 6 C. Preparation of an aqueous solution of known concentration from a solid chemical ................................ ......................... 7 D. Preparation of an aqueous solution of known concentration (standard solution) from a solid chemical for use in quantitative analysis ................................ .......................... 7 E. Temperature Measurement ................................ ............... 7 F. Filtration ................................ ................................ ............ 8 G. Heating ................................ ................................ .............. 8 H. Cooling ................................ ................................ .............. 8 I. Drying Glassware ................................ .............................. 8 J. Drying Solids ................................ ................................ ..... 8 K. Drying Liquids ................................ ................................ .... 9 L. Pressure of Gas................................ ................................ . 9 M. Gas Collection and Volume Measurement ......................... 9 N. Time Measurement ................................ .......................... 10 LABORATORY TECHNIQUES ................................ ........................... 10 A. Melting points ................................ ................................ .. 10 B. Recrystallisation ................................ .............................. 10 C. Liquid-liquid extraction ................................ ..................... 10 D. Distillation ................................ ................................ ........ 11 E. Reflux ................................ ................................ .............. 11 F. Evaporation ................................ ................................ ..... 12 CLASSICAL TECHNIQUES ................................ .............................. 12 A. Titrimetric / Volumetric Analysis (VA) ............................... 12 Acid-Base Titrations ................................ ........................ 12 Redox Titrations ................................ .............................. 13 Complexometric Titrations ................................ ............... 13 Precipitation Titrations ................................ ..................... 13 Eg 1 Determination of concentration of H3PO4 and NaH2PO4 in a mixture via double indicator titration with NaOH ................................ ............................. 14 Eg 2 Determination of percentage by mass of aspirin by back titration ................................ .......................... 14 Eg 3 Determination of concentration of K2C2O4 by titration with KMnO4. ................................ .......................... 15 Eg 4 Determination of concentration of CuSO4 by iodometric titration ................................ ................. 15 Eg 5 Determination of Al3+ concentration by complexometric back titration with Zn2+ .................. 15 Eg 6 Determination of silver in an alloy .......................... 16 Eg 7 Determination of a value for the solubility product, Ksp, of calcium iodate(V), Ca(IO3)2 ......................... 16 B. Gravimetric Analysis ................................ ........................ 17 Precipitation Gravimetry ................................ .................. 17 Volatilisation Gravimetry ................................ .................. 17 Eg 8 The gravimetric determination of chloride in a soluble sample. ................................ ................................ .. 17 Eg 9 The gravimetric determination of the percentage by mass of NaHCO3 in FA 1, a mixture containing NaHCO3 and NaCl................................ ................. 17 C. Calorimetry ................................ ................................ ...... 18 Calorimeter ................................ ................................ ...... 18 Heat Capacity ................................ ................................ .. 19 Specific Heat Capacity ................................ .................... 19 Measuring the Temperature Difference ........................... 19 Eg 10 Determination of the enthalpy change of reaction, Hr, of NaHCO3 (FA 1) with H2SO4 (FA 2) ............. 19 Eg 11 Determination of concentration of NaOH and enthalpy of reaction, Hr, between NaHCO3 and NaOH [Thermometric Titration] .............................. 20 Eg 12 Determination of concentration of H2SO4 and enthalpy of neutralisation, Hneu, of a strong acid by a strong base................................ ............................ 20 Eg 13 Determination of the enthalpy change of solution, Hsol, of potassium chloride, KCl (endothermic) ..... 21 Eg 14 Determination of heat capacity of calorimeter ........ 21 Eg 15 Determination of the enthalpy change of combustion, Hc, of octan-1-ol (extension from Eg 14) .............. 22 D. UV/Visible Spectrophotometry ................................ ......... 22 Principles of Light Absorption ................................ .......... 22 Eg 16 Determination of the formula of complex formed between aqueous iron(III) ions, Fe3+(aq), and aqueous 2-hydroxybenzoate ions, C6H4(OH)CO2– . 22 E. Kinetics ................................ ................................ ........... 23 Basic Terminology ................................ ........................... 23 Empirical Rate Equations and Approximations ................ 23 Conventional Monitoring Methods ................................ ... 23 Temperature Control and Measurement .......................... 24 Experimental Determination of Rate Equation ................. 24 Eg 17 Determination of the kinetics of the decomposition of thiosulfate ions ................................ ...................... 24 Eg 18 Determination of the rate equation for an iodine clock reaction ................................ ................................ . 25 Eg 19 Determination of the order of reaction for decomposition of benzenediazonium ion in water .. 25 Eg 20 Determination of the order of reaction with respect to iodine in the iodination of propanone reaction ........ 27 Eg 21 Determination of the activation energy for the iodination of propanone (extension from Eg 20) ..... 28 Eg 22 Determination of the activation energy for the iodination of propanone .........