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Slide 2 By Liz LaRosa revised by Karen Meadows www.middleschoolscience.comwww.middleschoolscience.com 2009 Classifying Matter: Elements, Compounds, and Mixtures Slide 3 Pure Substances A sample of matter that has definite chemical and physical properties. Slide 4 Elements pure substance that cannot be separated into simpler substance by physical or chemical means. Slide 5 Compounds Pure substance composed of two or more different elements joined by chemical bonds. Made of elements in a specific ratio that is always the same Has a chemical formula Can only be separated by chemical means, not physically Slide 6 Mixtures A combination of two or more pure substances that are not chemically combined. substances held together by physical forces, not chemical No chemical change takes place Each item retains its properties in the mixture They can be separated physically Chem4kids.com Slide 7 Mixtures vs. Compounds http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/elements_com_mix_6.shtml Slide 8 Can you identify the following? You will be shown a series of photos. Tell if each photo represents an item composed of an element, compound, or mixture. Review: An element contains just one type of atom. A compound contains two or more different atoms joined together. A mixture contains two or more different substances that are only physically joined together, not chemically. A mixture can contain both elements and compounds. Slide 9 Element, Compound, or Mixture? Rocks Slide 10 Element, Compound, or Mixture? Rocks Slide 11 Element, Compound, or Mixture? Copper Slide 12 Element, Compound, or Mixture? Copper Slide 13 Element, Compound, or Mixture? Jelly Beans Slide 14 Element, Compound, or Mixture? Jelly Beans Slide 15 Element, Compound, or Mixture? Table Sugar Slide 16 Element, Compound, or Mixture? Table Sugar Slide 17 Element, Compound, or Mixture? Diamond Slide 18 Element, Compound, or Mixture? Diamond Slide 19 Element, Compound, or Mixture? Tea Slide 20 Element, Compound, or Mixture? Tea Slide 21 Element, Compound, or Mixture? Salt Slide 22 Element, Compound, or Mixture? Salt Slide 23 Element, Compound, or Mixture? Neon Gas Slide 24 Element, Compound, or Mixture? Neon Gas Slide 25 Element, Compound, or Mixture? Salad Slide 26 Element, Compound, or Mixture? Salad Slide 27 Element, Compound, or Mixture? Pure Water Slide 28 Element, Compound, or Mixture? Pure Water Slide 29 Element, Compound, or Mixture? Aluminum Slide 30 Element, Compound, or Mixture? Aluminum Slide 31 Element, Compound, or Mixture? Lemonade Slide 32 Element, Compound, or Mixture? Lemonade Slide 33 Element, Compound, or Mixture? Silver Slide 34 Element, Compound, or Mixture? Silver Slide 35 Element, Compound, or Mixture? Sand Slide 36 Element, Compound, or Mixture? Sand Slide 37 Slide 38 Notes Detailed notes are located at: http://www.middleschoolscience.com/elements-compounds- mixtures-notes-isn.pdf Flow Chart: http://www.middleschoolscience.com/matter-flow-chart- isn.pdf Slide 39 Mixtures A combination of 2 or more substances that do not combine chemically, but remain the same individual substances Can be separated by physical means Two Types: 1. Heterogeneous 2. Homogeneous Slide 40 Heterogeneous Mixture Hetero means different Visibly different substances or phases (solid, liquid, gas) Suspension A special type of heterogeneous mixture A mixture of larger particles that eventually settle Slide 41 Homogeneous Mixture Homo means the same Has the same uniform appearance and composition throughout Maintains one phase (solid, liquid, gas) Commonly referred to as solutions Example: Salt water Slide 42 Slide 43 Methods of Separating Mixtures Slide 44 Filtration can be used to separate an insoluble substance from a soluble substance Slide 45 Slide 46 Slide 47 Slide 48 Slide 49 Evaporation can be used to separate a solute from the solvent in a solution Slide 50 Slide 51 Evaporation of sea water to produce salt Slide 52 Distillation allows the separation of a solvent from a solution Slide 53 Slide 54 Slide 55 Slide 56 A separating funnel can be used to separate two liquids which are immiscible Slide 57 Chromatography allows separation of different pigment colours Slide 58 Slide 59 A magnet Can be used to separate a magnetic substance from a non-magnetic substance