Elements, compounds and mixtures

1. Elements, compounds and mixtures

2. What is an element?

3. An element is… • material made of just one type of atom • A substance that can not be separated or broken down into simpler substances by chemical means

4. What are the 3 most abundant elements that make up the earth?

5. answer • Oxygen • Iron • silicon

6. Composition of the earth

7. What are 3 most common elements that make up a human being?

8. answer • Oxygen • Carbon • hydrogen

9. Elements that compose a human body

10. What is an Atom?

11. atom • The smallest unit of an element that maintains the properties of the element

12. What is a compound?

13. Compound • A substance made of two or more different elements that are combined chemically • Properties of compounds may not be the same as properties of elements that make them up

14. Compounds • Substances composed of 2 or more elements that have been chemically combined • Glass • Sugar • Water • Salt

15. compounds in real life • My gold ring • Water in a bottle • Metal cart • Copper wiring

16. Elements in real life • Neon lights • 24 Karat gold bar • Oxygen in a scuba tank

17. What is a molecule?

18. Molecule • The smallest amount of a compound that still retains the qualities of the compound • 1 molecule of water is composed of 2 hydrogen and 1 oxygen atom

19. Sugar molecule: Made up of atoms combined in a specific way Oxygen atoms are red, gray Carbon atoms are white Hydrogen are small white with red dots

20. Water on a molecular level

21. Comparisons and contrasts • Element and compound • Comparison: Both are pure substances • Contrast: Elements can only be composed of one type atom, Compounds are composed 2 or more types atoms (elements)

22. Atom and Molecule • Comparison: The smallest unit that still retains material’s properties • Contrast: Atom is the smallest unit of an element, Molecule is the smallest unit of a compound. Molecules can be composed of different types of atoms

23. What is a pure substance?

24. What does it mean to be a pure substance? “100% pure Honey” “100% pure salt or sugar”

25. Pure substance • Substance composed of either a single type of element or compound chemically combined • If a Compound, a pure substance has a fixed composition or proportions of elements • every molecule of water has 2 hydrogen and one oxygen atom • All compounds can be written with a chemical formula

26. Pure Substance • An amount of matter , either single element or one compound that exhibits distinct chemical and physical properties • Table Salt (if just made with NaCl) is a pure substance • Grape Juice is not (Water, Sugars, Vitamins)

27. What is a mixture?

28. Mixture • A combination of 2 or more pure substance combined physically • Classified by how thoroughly they are mixed • Properties of mixture similar to properties of components

29. Mixtures • If you can separate the substances, it’s a mixture • If it has ingredients, it’s a mixture

30. Types of Mixtures • Heterogeneous • Homogeneous • Miscible • Immiscible • Alloy

31. Heterogeneous mixture • Mixtures with ingredients that do not mix well or stay mixed long • Examples: Chocolate syrup and milk

32. Homogeneous Mixture • Mixtures that mix very well • Solutions where substances dissolve well into each other • Can not visually see any separation of the ingredients • Examples: Gasoline, Soda

33. Pure substance and mixtures • Comparison: both are composed of elements • Contrast: Pure substance is composed of an element or compound whose composition is fixed. Mixture is composed of a combination of pure substances whose composition can vary

34. What is the difference between heterogeneous and homogeneous mixtures?

35. Heterogeneous and homogeneous mixtures • Comparisons: both mixtures • Contrast: Heterogeneous materials do not mix well or evenly. They are easily separated. Homogeneous mixtures do mix well and evenly, not easily separated

36. Difference… • Heterogeneous mixtures: are mixtures of 2 or more substances that are not completely soluble (bits of each are seen in mixture) • Homogeneous mixtures: are mixtures of 2 or more substances that are completely soluble (blend completely, can not tell components)

37. Miscible mixture • Extremely homogeneous • Dissolves completely • Example: Air

38. Miscibilitity • How well substances mix together • The greater the ability to mix (solubility), the more miscible it is. • Oil and water are immiscible (insoluble) • Carbon dioxide and water (very soluble)

39. Immiscible mixture • Extremely heterogeneous • Don’t mix well at all • Examples water and granite

40. Immiscible Mixture Gasoline, Soda

41. Solubility • Measurement of the ability of one substance (solute) to dissolve into another substance (solvent)

42. What is an alloy?

43. Alloy • An alloy is a solid homogenous mixture of two or more metals. • The there is not chemical reaction occurring, and the original materials can be recreated by melting. • There are thousands of different alloys, and people use them for many different purposes.

44. Different common alloys