1. Magnetic Attraction 7 Fun stuff! Research online for “ferrofluid” and find out how it works!
1. Magnetic Attraction 8 Uses: Scrapyards use strong electromagnets to salvage scrap iron and steel from other junk materials separating magnetic ores from non-magnetic ones in mining food processing
1. Magnetic Attraction 9 Let’s see a magnetic crane in action!
Uses of Evaporation 23 To obtain salt from sea water
24 Devil’s Golf Course, Death Valley National Park, California. Evaporated salt has formed into gnarled, complex crystalline shapes in on the salt pan, one of the largest in the world. The shapes are constantly evolving as occasional floods submerge the salt concretions before receding and depositing more salt.
Evaporation 25 Used to separate a dissolved solidfrom a liquid in a solid-liquid mixture. residue mixture
Distillation 26 Arnold Bochmove (1235 - 1310) gave recipes for liqueurs based on distilling wine with spices and herbs. Distillation of wine to produce gin and liqueurs became known in Paris by 1332 and spread throughout Europe.
Oil refineries use fractional distillation to separate crude oil into useful product such as petrol, diesel and kerosene
How can we help? Ahmad the fisherman wishes to use salt to make some salted fish. But he has run out of salt supply! He knows that seawater contains salt. How can we help him obtain pure salt from seawater containing sand and pebbles? Dried Salted Fish
How can we help?? How can Ahmad get pure water from the seawater? Ahmad spotted some shimmering specks in the sand mixture which he thinks is iron metal. How can Ahmad get the iron? Ahmad accidentally spilled his bottle of wine(alcohol) into a pail of seawater. How can he obtain the wine again?
Paper Chromatography 40 Used to separate small amounts of mixtures Makes use of the fact that different substances dissolve to different extent in a solvent move at different rates through any particular solvent/medium.
Paper chromatography is used to identify the contents of a mixture or to test the purity of a liquid. 41 Different substances in the mixture are separated on the chromatography paper.
Uses of Paper Chromatography 42 Can be used to separate mixtures of coloured substances such as ink and dyes. e.g. dyes used in ink dyes used in food
Food for thought 44 How do you think forensic scientists make use of tiny amount of DNA available to make identifications? Hint: the method uses similar principle as paper chromatography. Do some research online!
What is “osmosis”? 46 Move of water molecules across a partially permeable membrane from a region of high water potential (in other words, low solute concentration) to a region of low water potential (i.e. high solute concentration).
Reverse osmosis 51 a filtration method removes many types of large molecules and ions from solutions by applying high pressure to the solution when it is on one side of a partially permeable membrane. Solutes are retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side.
Applications of Reverse Osmosis 52 Can be used for desalination Sea water is pre-treated to remove debris and contaminants pumped at high pressure through partially permeable membranes removes all traces of bacteria, viruses, chemicals and dissolved minerals