NotesDownload the presentation hereStructured Question Worked Solutions1. Select from the following list, one method by which each of the following may be separated from the stated mixture. You may use a method once, more than once, or not at all.chromatography precipitation filtration distillation sublimation electrolysis crystallisation reduction oxidation synthesis a. red dye from a mixture of red and blue dyes in solution b. oxygen from liquid air c. barium sulphate from a mixture of barium sulphate and water d. ammonium chloride from a mixture of ammonium chloride and sodium chloride e. amino acids from a mixture obtained by the hydrolysis of a protein Solution 1a. chromatography 1b. distillation 1c. filtration 1d. sublimation 1e. chromatography 2. Name the apparatus that is most suitable for a. measuring exactly 23.4cm3 of liquid b. mixing 100cm3 of two liquids c. measuring about 20cm3 of liquid d. measuring exactly 10cm3 of liquid Solution 2a. Burette 2b. Beaker 2c. Measuring cylinder 2d. Pipette 3. Given a mole of ammonia gas and carbon dioxide, arrange in ascending order the mass and density of ammonia gas, carbon dioxide and air. Solution For 1 mole of NH3, CO2 and air (79% N2 and 21% O2) at fixed volume, mass of NH3 = 14 + 3(1) = 17g mass of CO2 = 12 + 2(16) = 44g mass of air = 0.79[2(14)] + 0.21[2(16)] = 28.8g Therefore, arrange in ascending order of mass and density: NH3, air, CO2. |
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