Matter and Energy

1. Matter and Energy Chapter 3

2. A System – What is being studied • Universe = System + Surroundings (everything else not being studied) • Matter is the part of the system that has mass and volume • Energy is the part of the system that has the ability to do work • Chemistry is primarily the study of matter • The properties of different types of matter • The way matter behaves when influenced by other matter and/or energy

3. Definition of Properties of Matter • Properties of Matterare characteristics of the substance under observation • Properties can be either • directly observable or • the manner in which something interacts with other substances in the system or in the surroundings

4. Why does soda fizz when you open the bottle?

5. Properties of Matter • Physical Properties are the characteristics of matter that can be changed without changing its composition • Characteristics that are directly observable • Chemical Properties are the characteristics that determine how the composition of matter changes as a result of contact with other matter or the influence of energy • Characteristics that describe the behavior of matter

6. Classify Each of the following as Physical or Chemical Properties • The boiling point of ethyl alcohol is 78°C. • Diamond is very hard. • Sugar ferments to form ethyl alcohol.

7. ANSWERS - Classify Each of the following as Physical or Chemical Properties • The boiling point of ethyl alcohol is 78°C. • Physical property – describes inherent characteristic of alcohol – boiling point • Diamond is very hard. • Physical property – describes inherent characteristic of diamond – hardness • Sugar ferments to form ethyl alcohol. • Chemical property – describes behavior of sugar – forming a new substance (ethyl alcohol)

8. States of Matter • The three common states of matter are solid, liquid, and gas. • Plasma is not a common state of matter. • A plasma is a very hot gaseous fluid of ionized particles, meaning that the particles have an electrical charge. • A place to find matter in a plasma state is in the sun.

9. Comparison of the States of Matter

10. Said Another Way…

11. Figure 3.1: Liquid water takes the shape of its container.

12. An iron pyrite crystal (gold color) on a white quartz crystal. Source: Chip Clark

13. At the Molecular Level • The molecules in a fluid are able to move freely, that is to flow. • Thus, liquids and gases are fluids. • Viscosity is a measure of the resistance of a fluid to flowing. • A highly viscous fluid flows more slowly than a low-viscosity fluid. • Don’t confuse viscosity with density!

14. Molecular Motion in a Solid Figure 3.11: In ice, the water molecules vibrate randomly about their positions in the solid. Their motions are represented by arrows.

15. Elements and Compounds • Substances which can not be broken down into simpler substances by chemical reactions are called elements • Most substances are chemical combinations of elements. These are called compounds. • Compounds are made of elements that are chemically bonded to each other • Compounds can be broken down into elements • Properties of the compound not related to the properties of the elements that compose it • Same chemical composition at all times

16. Classification of Matter • Homogeneous = uniform throughout, appears to be one thing • pure substances (elements and compounds by themselves) • solutions (homogeneous mixtures) • Heterogeneous = non-uniform, contains regions with different properties than other regions of a mixture

17. Pure Substances vs. Mixtures • Pure Substances • All samples have the same physical and chemical properties • Constant Composition  all samples have the same composition • Homogeneous • Separate into components based on chemical properties • Mixtures • Different samples may show different properties • Variable composition • Homogeneous or Heterogeneous • Separate into components based on physical properties • All mixtures are made of pure substances

18. Identity Each of the following as a Pure Substance, Homogeneous Mixture or Heterogeneous Mixture • Gasoline • A stream with gravel on the bottom • Copper metal

19. ANSWERS - Identity Each of the following as a Pure Substance, Homogeneous Mixture or Heterogeneous Mixture • Gasoline • a homogenous mixture • A stream with gravel on the bottom • a heterogeneous mixture • Copper metal • A pure substance (all elements are pure substances)

20. Figure 3.10: The organization of matter.

21. HOMEWORK • READ/STUDY Sections 3-1, 3-3, and 3-4 • ANSWER the questions on "Ch. 3 Worksheet 1" - DUE THURSDAY, 9/20. • DO your Ch. 2 Test error analysis/corrections with explanations BY FRIDAY for extra points.

22. Things to do … • Get a copy of “Chapter 3 Worksheet 2” from the counter. This is tonight’s homework, due tomorrow. • Get a copy of “Chapter 3 Worksheet 3” from the counter. This is tomorrow night’s homework, due Thursday, 9/28.

23. A creation foundation Your word, O LORD, is eternal; it stands firm in the heavens. Psalm 119:89 Ref. 11-9

24. Mixture Separation Techniques Decanting Filtration Extraction Evaporation Distillation Miscellaneous Techniques

25. Decanting • A fancy word for pouring • Supernatant is a fancy word for the liquid portion of the mixture. • Used to separate an insoluble solid from a liquid CLICK PICTURE to the right to start video.

26. Filtration • Filtration uses a filter paper or fine porous ceramic to separate a solid from a liquid. • The solid remains in the filter paper and the liquid goes through the paper into the beaker. • It works because the tiny dissolved particles are too small to be filtered BUT any non-dissolved solid particles are too big to go through CLICK PICTURE to the right to start video.

27. Additional Filtering Information CLICK PICTURES to start video.

28. Evaporation • Evaporation means a liquid changing to a gas or vapor. • In separation, its removing the liquid from a solution, usually to leave a solid. • It can be done quickly with gentle heating or left out to 'dry up' slowly. • The solid will almost certainly be less volatile than the solvent and will remain as a crystalline residue.

29. Extraction • One variation uses a solvent (like water) to selectively dissolve one component of the solid-solid mixture. • With this technique, a soluble solid can be separated from an insoluble solid. • Usually followed by filtration and evaporation. • Example – separating salt from sand

30. Distillation • Distillation involves 2 stages and both are physicalstatechanges. • (1) The liquid or solution mixture is boiled to vaporize the most volatile component in the mixture (liquid ==> gas). The ant-bumping granules give a smoother boiling action. • (2) The vapor is cooled by cold water in the condenser to condense (gas ==> liquid) it back to a liquid (the distillate) which is collected.

31. Fractional Distillation • It can only work with liquids with different boiling points. However, this method only works if all the liquids in the mixture are miscible and do NOT separate out into layers like oil/water. • (1) The liquid or solution mixture is boiled to vaporize the most volatile component in the mixture (liquid ==> gas). • (2) The vapor passes up through a fractionating column, where the separation takes place (theory on next slide). • (3) The vapor is cooled by cold water in the condenser to condense (gas ==> liquid) it back to a liquid (the distillate) which is collected. • This can be used to separate alcohol from a fermented sugar solution. • It is used on a large scale to separate the components of crude oil, because the different hydrocarbons have different boiling and condensation points

32. Fractional Distillation Theory Imagine green liquid is a mixture of a blue liquid (boiling point 80 oC) and a yellow liquid (boiling point 100 oC), so we have a colored diagram simulation of a colorless alcohol and water mixture! As the vapor from the boiling mixture enters the fractionating column it begins to cool and condense. The highest boiling or least volatile liquid tends to condense more i.e. the yellow liquid (water). The lower boiling more volatile blue liquid gets further up the column. Gradually up the column the blue and yellow separate from each other so that yellow condenses back into the flask and pure blue distills over to be collected. The 1st liquid, the lowest boiling point, is called the 1st fraction and each liquid distills over when the top of the column reaches its particular boiling point to give the 2nd, 3rd fraction etc.

33. Fractional Distillation (continued) • To increase the separation efficiency of the tall fractionating column, it is usually packed with glass beads, short glass tubes or glass rings etc. which greatly increase the surface area for evaporation and condensation.  • In the distillation of crude oil the different fractions are condensed out at different points in a huge fractionating column. At the top are the very low boiling fuel gases like butane and at the bottom are the high boiling big molecules of waxes and tar.

34. Paper Chromatography Process The concept behind this techniques is that different constituent in a mixture have different solubility. As the solvent moves up the paper the less soluble constituent will travel at a slower rate than those of more soluble constituents. Hence the mixture will eventually separate into different colored spots as the solvent moves to the top. CLICK PICTURE to the right to start video.

35. Types of Chromatography • Liquid Chromatography is used in the world to test water samples to look for pollution in lakes and rivers. It is used to analyze metal ions and organic compounds in solutions. Liquid chromatography uses liquids which may incorporate hydrophilic, insoluble molecules. • Gas Chromatography is used in airports to detect bombs and is used is forensics in many different ways. It is used to analyze fibers on a persons body and also analyze blood found at a crime scene. In gas chromatography helium is used to move a gaseous mixture through a column of absorbent material. • Thin-layer Chromatography uses an absorbent material on flat glass or plastic plates. This is a simple and rapid method to check the purity of an organic compound. It is used to detect pesticide or insecticide residues in food. Thin-layer chromatography is also used in forensics to analyze the dye composition of fibers. • Paper Chromatography is one of the most common types of chromatography. It uses a strip of paper as the stationary phase. Capillary action is used to pull the solvents up through the paper and separate the solutes.

36. Separatory Funnels A separatory funnel is useful for performing extractions. Extraction is one way of purifying a substance. In an extraction, a solute is transferred from one solvent to another. One type of extraction involves removing polar solutes from an organic solvent that is immiscible with water. The organic solution and water are added to the separatory funnel, shaken, and allowed to separate into layers. The polar molecules preferentially dissolve in the water, and because the organic solvent and the water are immiscible, the water layer may be separated from the organic layer. By this process, a polar compound can be isolated from impurities, which remain in the organic phase.

37. Using a Separatory Funnel First, fill the separatory funnel. Next, mix things. Finally, drain the funnel.

38. Mixture Separation Examples • (1) separating dyes in inks, or chlorophyll in plants (ethanol as solvent) – chromatography; • (2) separating sand from water – filtration; • (3) separating ethanol and water – fractional distillation; • (4) separating water from ink – simple distillation; • (5) separating salt from water – evaporation

39. Things to do … • Turn in Ch. 3 Worksheet 2 on the counter. It is due NOW at the beginning of class. NO LATE WORK ACCEPTED.

40. Physical vs. Chemical Properties and Changes Section 3-2

41. Gallium metal has such a low melting point (30°C) that it melts from the heat of a hand.Is a physical or chemical change taking place?

42. Oxygen combines with the chemicals in wood to produce flames.Is a physical or chemical change taking place?

43. Changes in Matter • Physical Changes are changes to matter that do not result in a change the fundamental components that make that substance • State Changes – boiling, melting, condensing • Chemical Changes involve a change in the fundamental components of the substance • Produce a new substance • Chemical reaction • Reactants  Products

44. Classify Each of the following as Physical or Chemical Changes • Iron metal is melted. • Iron combines with oxygen to form rust. • Sugar ferments to form ethyl alcohol.

45. Classify Each of the following as Physical or Chemical Changes • Iron is melted. • Physical change – describes a state change, but the material is still iron • Iron combines with oxygen to form rust.. • Chemical change – describes how iron and oxygen react to make a new substance, rust • Sugar ferments to form ethyl alcohol. • Chemical change – describes how sugar forms a new substance (ethyl alcohol)

46. Different Physical Property Technique Boiling Point Distillation State of Matter (solid/liquid/gas) Filtration Adherence to a Surface Chromatography Volatility (n.); volatile (adj.) Evaporation Separation of Mixtures • Separate mixtures based on different physical properties of the components • Physical change

47. IN CONTRASTFigure 3.3: Electrolysis, the decomposition of water by an electric current, is a chemical process.

48. HOMEWORK • COMPLETE Ch. 3 Worksheet 3 • READ Lab 2 and design your lab group’s mixture separation technique. Outline measurements you will need to make in order to determine the mass of each component of the mixture. • REVIEW ALL of your Ch. 3 notes that you have so far.

49. Energy, Heat, and Temperature Sections 3-6 and 3-7 TEST on Ch. 3 on FRIDAY, 10/5.

50. Energy and Energy Changes • Capacity to do work • chemical, mechanical, thermal, electrical, radiant, sound, nuclear • Energy may affect matter • e.g. raise its temperature, eventually causing a state change • All physical changes and chemical changes involve energy changes