1. Chapter 3 MATTER

2. Section 3.1 The Particulate Nature of Matter Objective: Learn about the composition of matter Learn about the composition of matter

3. Matter Matter is anything that: a) has mass, and a) has mass, and b) takes up space b) takes up space Mass = a measure of the amount of “stuff” (or material) the object contains (don’t confuse this with weight, a measure of gravity) Volume = a measure of the space occupied by the object

4. What about atoms? All matter is made up of tiny particles called ATOMS Although objects look quite continuous and uniform, they are really particulate in nature Atoms are not all alike About 100 different types of atoms make up all the different types of matter Think of the alphabet (atoms) and words (matter) Think of the alphabet (atoms) and words (matter)

5. Section 3.3 Elements and Compounds Objective: The difference between a element & compound The difference between a element & compound

6. Element, Compound or Molecule simplest kind of matter Elements simplest kind of matter cannot be broken down any simpler and still have properties of that element! cannot be broken down any simpler and still have properties of that element! all one kind of atom. all one kind of atom. Compounds are substances that can be broken down only by chemical methods when broken down, the pieces have completely different properties than the original compound. when broken down, the pieces have completely different properties than the original compound. made of two or more different atoms, chemically combined (not just a physical blend!) made of two or more different atoms, chemically combined (not just a physical blend!) Molecules are substances that can be broken down only by chemical methods made of two or more atoms, chemically combined (not just a physical blend!) made of two or more atoms, chemically combined (not just a physical blend!)

7. A molecule is what you get when any atoms join together. A compound is what you get when atoms of two or more different elements join together. All compounds are molecules, but not all molecules are compounds. Water is a molecule because it is made from atoms that have been chemically combined. It is also a compound because the atoms that make water are not all the same - some are Water is a molecule because it is made from atoms that have been chemically combined. It is also a compound because the atoms that make water are not all the same - some are oxygen and some are hydrogen. Oxygen in the atmosphere is a molecule because it is made from two atoms of oxygen. It is not a compound because it is made from atoms of only one element - oxygen. This type of molecule is called a diatomic molecule, a molecule made from two atoms of the same type. I am not clear on what a molecule is. If water is a molecule, is it also a compound because the hydrogen and oxygen have been chemically combined? If so, how do you determine whether a substance is a compound or a molecule?

8. Elements vs Compounds Currently, there are 117 elements Elements have a 1 or two letter and compounds have a formula. Elements have a 1 or two letter symbol, and compounds have a formula. An ;, : B, Ba, C, Ca, H, He An element’s first letter always capitalized; if there is a second letter, it is written lowercase: B, Ba, C, Ca, H, He Some names come from Latin or other languages

9. Compounds vs Elements be broken down into simpler substances by chemical means, but Compounds can be broken down into simpler substances by chemical means, but elements cannot. Compounds always contain atoms of different elements…..Always in the same composition Ex. Water is always found as 2 hydrogen atoms combined with 1 oxygen atom

10. Atom Combinations

11. Compound vs. Mixture Compound vs. Mixture *we will come back to mixtures later CompoundMixture Made of one kind of material Made of more than one kind of material Made by a chemical change Made by a physical change Definite composition Variable composition

12. Which is it?

13. Element

14. Which is it?

15. Compound

16. Which is it?

17. Mixture

18. Which is it?

19. Molecule

20. States of Matter Objective: To define the 3 states of matter To define the 3 states of matter

21. States of matter 1)Solid- matter that can not flow (definite shape) and has definite volume. 2)Liquid- definite volume but takes the shape of its container (flows). 3)Gas- a substance without definite volume or shape and can flow. Vapor- a substance that is currently a gas, but normally is a liquid or solid at room temperature. (Which is correct: “water gas”, or “water vapor”?) * Vapor- a substance that is currently a gas, but normally is a liquid or solid at room temperature. (Which is correct: “water gas”, or “water vapor”?)

22. States of Matter Solid Liquid Gas Definite Volume? YES NO Definite Shape? YES NO Result of a Temperature Increase? Small Expands. Large Expands. Will it Compress? NO YES

23. 4 th state: Plasma - formed at high temperatures; ionized phase of matter as found in the sun

24. Three Main Phases Solids – molecule are locked into fixed positions….little movement to move Liquids – molecules can slide past one another Gas – a free to move randomly about

25. Copper Phases - Solid

26. Copper Phases - Liquid

27. Copper Phases – Vapor (gas)

28. Solid Liquid Gas Melt Evaporate Condense Freeze

29. Section 3.2 Physical/Chemical Properties and Changes Objective: To distinguish between physical and chemical properties To distinguish between physical and chemical properties To distinguish between physical and chemical changes To distinguish between physical and chemical changes

30. Properties are… Words that describe matter (adjectives) Physical Properties- a property that can be observed and measured without changing the material’s composition. Describes individual characteristics Examples- color, hardness, m.p., b.p. Chemical Properties- a property that can only be observed by changing the composition of the material. Describes social characteristics Examples- ability to burn, decompose, ferment, react with, etc.

31. Physical vs. Chemical Change Physical change will change the visible appearance, without changing the composition of the material. Boil, melt, cut, bend, split, crack Boil, melt, cut, bend, split, crack Is boiled water still water? Is boiled water still water? Can be reversible, or irreversible Can be reversible, or irreversible Chemical change - a change where a new form of matter is formed. Rust, burn, decompose, ferment Rust, burn, decompose, ferment

32. Recognizing Chemical Changes 1)Energy is absorbed or released (temperature changes hotter or colder) 2)Color changes 3)Gas production (bubbling, fizzing, or odor change; smoke) 4)formation of a precipitate - a solid that separates from solution (won’t dissolve) 5)Irreversibility - not easily reversed But, there are examples of these that are not chemical – boiling water bubbles, etc.

33. Separation of a Mixture Objective: Learn 2 methods of separating mixtures Learn 2 methods of separating mixtures

34. Mixtures vs Pure substance Section 3.4 Mixtures vs Pure substance Objective: To distinguish between mixtures and pure substances To distinguish between mixtures and pure substances

35. Mixtures Mixtures - are a physical blend of at least two substances; have variable composition. They can be either: 1)Heterogeneous– the mixture different it is not uniform in composition 1)Heterogeneous – the mixture different it is not uniform in composition Chocolate chip cookie, gravel, soil.Chocolate chip cookie, gravel, soil. Homogeneous- same composition throughout; called “solutions” 2.) Homogeneous - same composition throughout; called “solutions” Kool-aid, air, salt waterKool-aid, air, salt water Every part keeps it’s own properties.

36. Solutions are homogeneous mixtures Mixed molecule by molecule, thus too small to see the different parts Can occur between any state of matter: gas in gas; liquid in gas; gas in liquid; solid in liquid; solid in solid (alloys), etc. Thus, based on the distribution of their components, mixtures are called homogeneous or heterogeneous.

37. Alloy – mixture of metals Twenty-four-karat gold is an element Eighteen-karat gold is an alloy. Fourteen-karat gold is an alloy. * Twenty-four-karat gold is an element Eighteen-karat gold is an alloy. Fourteen-karat gold is an alloy. *An alloy is a mixture or metallic solid solution composed of two or more elements

38. Classification of Matter

39. Pure Substances Pure substances – always have same composition Either elements or compounds Either elements or compounds Ex pure water is a pure substance – it only contains H 2 O molecules Tap water is a mixture – it contains H 2 O and other minerals such as calcium and magnesium

40. Section 3.5 Separation of Mixtures Objective: Learn 2 methods of separating a mixture Learn 2 methods of separating a mixture

41. Separating Mixtures Some can be separated easily by physical means: rocks and marbles, iron filings and sulfur (use magnet) Differences in physical properties can be used to separate mixtures. Filtration - separates a solid from the liquid in a heterogeneous mixture (by size) – Figure 2.7, page 46

42. Separation of a Mixture Distillation: takes advantage of different boiling points. NaCl boils at 1415 o C

43. Another view of Distillation

44. Filtration separates a liquid from a solid. Filtration separates a liquid from a solid.

45. Separation of a sand-saltwater mixture Separation of a sand-saltwater mixture To separate sand-saltwater mixture: first use filtration to separate sand from saltwater then use distillation to separate salt and water

46. Chapter 3 The End