Always have the same composition and are formed by chemical processes. Pure Substances Always have the same composition and are formed by chemical processes. Either elements or compounds. Examples: Pure water (H2O), carbon dioxide (CO2), hydrogen (H2), gold (Au) Copyright © Cengage Learning. All rights reserved

Have variable composition. Examples Wood, wine, coffee, granite Mixtures Have variable composition. Examples Wood, wine, coffee, granite Can be separated into pure substances: elements and/or compounds using physical processes.

Having visibly indistinguishable parts. A solution. Homogeneous Mixture Same throughout. Having visibly indistinguishable parts. A solution. Does not vary in composition from one region to another. Apple Juice Salt and water Orange Juice

Heterogeneous Mixture Having visibly distinguishable parts. Contains regions that have different properties from those of other regions.

How can mixtures be separated? If you have a salad containing an ingredient you don't like, how can you remove it? This ppt introduces and reviews ways of separating mixtures

Physical properties-Separation techniques Melting point Boiling point Freezing point Density Electrical conductivity Magnetic Particle size

a) Magnet b) Filtration c) Chromatography d) Distillation Separation techniques How can we physically separate (purify) substances from mixtures and solutions into pure substances? a) Magnet b) Filtration c) Chromatography d) Distillation Physical means are those that do not change the nature of the substances being separated.

A magnet Can be used to separate a magnetic substance from a non-magnetic substance (Magnetic properties) Magnets are used in the re-cycling industry to separate ferrous and non ferrous metals.

Filtration Funnel Filtration can be used to separate an insoluble substance from a soluble substance (heterogenous mixture) Ex. Coffee grounds are separated by water through filtration Solid Here you can introduce the terms Filtrate and residue. Liquid

Chromatography From Greek Chroma which means "color" and graphein "to write" Used to separate complex mixtures that rely on the differential affinities of substances Ex. Paper chromatography separate black ink into the colored dyes it contains.

Separate substances that have different boiling points Distillation Separate substances that have different boiling points Ex. Separating alcohol from water Boiling pt of alcohol is 70 C. Boiling pt of water is 100 C. The liquid is boiled to produce a vapor that is then condensed into a liquid.

Separating a Heterogeneous Mixture Sample Problem Separating a Heterogeneous Mixture How could a mixture of aluminum nails and iron nails be separated? Analyze Identify the relevant concepts. 1 In order to identify how to separate aluminum and iron nails, the properties of both aluminum and iron must be known. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved

Solve Apply concepts to this situation. Sample Problem Solve Apply concepts to this situation. 2 List the properties of each substance in the mixture. Iron metal gray color doesn’t dissolve in water attracted to magnet Aluminum metal gray color doesn’t dissolve in water not attracted to magnet You could use a magnet to remove the iron nails from a mixture of iron and aluminum.

Distillation relies on the boiling point of the substance. Which physical property does filtration rely on to separate mixtures? Which does distillation rely on? Filtration relies on the size of a particle, or molecule, of a substance. Distillation relies on the boiling point of the substance.

Classification of Matter