[CHEM] Chapter 1.2 - Separation Techniques

1 DARRELL ER (COPYRIGHTED) TOPIC 1.2: SEPARATION TECHNIQUES DARRELL ER (COPYRIGHTED) ©

2 CHAPTER ANALYSIS THE ABOUT TIME EXAM WEIGHTAGE • Relatively straight forward chapter • 2 key concepts • 4 advanced concepts • Usually tested in MCQs 🡪 2009 (3), 2012 (1), 2013 (2), 2014 (2), 2015 (1) • Tested as add-on to other chapters 🡪 Salts, Fuels & Crude Oil • Light overall weightage • Constitute to 0.5% of marks for past 5 year papers DARRELL ER (COPYRIGHTED) ©

3 9 DIFFERENT SEPARATION TECHNIQUES FILTRATION EVAPORATION CRYSTALLISATION SUBLIMATION MAGNETIC DARRELL ER (COPYRIGHTED) ©

4 DIFFERENT SEPARATION TECHNIQUES 9 IN TOTAL DISTILLATION FRACTIONAL DISTILLATION SEPARATING FUNNEL CHROMOTO GRAPHY DARRELL ER (COPYRIGHTED) ©

Pure Substance Impure Mixture Definition Only one type of substance Two or more substances Physical properties Fixed proportion Any ratio Fixed M.P. & B.P. Have a range of M.P. & B.P. Single spot on chromatogram Multiple spots on a chromatogram 5 PURE SUBSTANCE VS IMPURE MIXTURE MUST KNOW DARRELL ER (COPYRIGHTED) ©

6 Compound Mixture Formation Chemically combined Physically combined Separation technique Can be separated using chemical methods (Decomposition, electrolysis, reduction with carbon) Can be separated using physical methods (separation techniques) Composition Fixed ratio Any ratio m.p/b.p Fixed mp & bp Have a range of M.P. & B.P. MUST KNOW COMPOUND VS MIXTURE DARRELL ER (COPYRIGHTED) ©

7 Let’s get over the 3 simpler ones first FILTRATION MAGNETIC SEPARATING FUNNEL DARRELL ER (COPYRIGHTED) ©

8 FILTRATION MUST KNOW 1) Put a filter paper onto the filter funnel. 2) Pour the mixture into the filter funnel. 3) The residue will remain in the filter funnel while the filtrate will be collected in the beaker. DARRELL ER (COPYRIGHTED) ©

9 SEPARATING FUNNEL (IMMISCIBLE LIQUIDS) MUST KNOW 1) Oil and water are immiscible (do not dissolve with each other). 2) Oil which is less dense than water will float on top of water. 3) Open the tap and collect the water in a beaker. 4) Drain out the leftover water and some of the oil and throw the impure mixture away. 5) Collect the remaining oil in a separate beaker. DARRELL ER (COPYRIGHTED) ©

10 MAGNETIC SEPARATION MUST KNOW Magnetic separation is used to separate magnetic material from a mixture with other non-magnetic materials. (Scrapeyard) N I C S ickel ron obalt teel Magnetic Materials St’ Nics girls are pretty right? Know a Nicholas that is handsome? Are you attracted? That’s right, magnetic material. DARRELL ER (COPYRIGHTED) ©