Classifying Matter: Elements, Compounds, and Mixtures

1. Classifying Matter:Elements, Compounds, and Mixtures By Liz LaRosa revised by Karen Meadows www.middleschoolscience.com 2009

2. Pure Substances • A sample of matter that has definite chemical and physical properties. Atoms Elements Compounds Molecules

3. Elements • pure substance that cannot be separated into simpler substance by physical or chemical means.

4. 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 H2O NaCl CO2

5. 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

6. Mixtures vs. Compounds http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/elements_com_mix_6.shtml

7. 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.

8. Element, Compound, or Mixture? Rocks

9. Element, Compound, or Mixture? Rocks

10. Element, Compound, or Mixture? Copper

11. Element, Compound, or Mixture? Copper Cu

12. Element, Compound, or Mixture? Jelly Beans

13. Element, Compound, or Mixture? Jelly Beans

14. Element, Compound, or Mixture? Table Sugar

15. Element, Compound, or Mixture? Table Sugar C12H22O11

16. Element, Compound, or Mixture? Diamond

17. Element, Compound, or Mixture? Diamond C

18. Element, Compound, or Mixture? Tea

19. Element, Compound, or Mixture? Tea

20. Element, Compound, or Mixture? Salt

21. Element, Compound, or Mixture? NaCl Salt

22. Element, Compound, or Mixture? Neon Gas

23. Element, Compound, or Mixture? Ne Neon Gas

24. Element, Compound, or Mixture? Salad

25. Element, Compound, or Mixture? Salad

26. Element, Compound, or Mixture? Pure Water

27. Element, Compound, or Mixture? Pure Water H2O

28. Element, Compound, or Mixture? Aluminum

29. Element, Compound, or Mixture? Aluminum Al

30. Element, Compound, or Mixture? Lemonade

31. Element, Compound, or Mixture? Lemonade

32. Element, Compound, or Mixture? Silver

33. Element, Compound, or Mixture? Silver Ag

34. Element, Compound, or Mixture? Sand

35. Element, Compound, or Mixture? Sand

37. 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

38. 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: • Heterogeneous • Homogeneous

39. 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

40. 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

42. Methods of Separating Mixtures

43. Filtration can be used to separate an insoluble substance from a soluble substance

48. Evaporation can be used to separate a solute from the solvent in a solution

50. Evaporation of sea water to produce salt