Chapter 1 Matter, Measurement, and Problem Solving

1. Chemistry: A Molecular Approach, 1st Ed.Nivaldo Tro Chapter 1Matter,Measurement, and Problem Solving Ms. Knick HAHS Honors Chemistry 1A 2008, Prentice Hall

2. What Is Chemistry? • Observation: is sand different than water • Test the similarities and differences between sand and water. • Composition • Types & number of atoms, structure, • Properties • Chemical: how hot, how fast • Physical: size, ability to loose/gain electrons Chemistry is the study of the composition and properties of matter. Tro's "Introductory Chemistry", Chapter 1

3. Matter • Matter is anything that has mass and takes up space (volume) Tro, Chemistry: A Molecular Approach

4. Structure Determines Properties • Everything is made of tiny particles called atoms and molecules. • Chemists study these particles, looking at the kinds, numbers, structure, size which produce varying chemical and physical properties.

5. 6 Branches of Chemistry • Organic Chemistry- The study of most carbon containing compounds. Example: C6H12O6 (Sugar)

6. 6 Branches of Chemistry 2. Inorganic Chemistry- The study of all substances that do not contain carbon. Example: H2O (Water)

7. 6 Branches of Chemistry 3. Physical Chemistry- the study of the properties, changes, and relationship between energy and matter

8. 6 Branches of Chemistry • Analytical chemistry- the identification of the components and composition of materials.

9. 6 Branches of Chemistry 5. Biochemistry- the study of substances and processes occurring in living things. Example: Photosynthesis

10. 6 Branches of Chemistry 6. Theoretical Chemistry- the use of mathematics and computers to design and predict the properties of new compounds.

11. The Feces Question: • 5 chemists from each of the 5 branches of chemistry are out hiking the Appalachian trail on a cold day. They come upon some fresh, steaming pile of dung…..GROSS!!! Did it come from a rabbit? A deer? A bear?! Or worse… a human being?!?! So the question remains….WHO DUNG IT?!?!?

12. With all the chemist abilities they will be able to figure this out!!!

13. Measures the amount of lead in a blood sample. Study non-carbon-based chemicals in rocks Investigate changes that occur when food is digested in the stomach Study carbon based chemicals in coal Explain the energy transfer that occurs when ice melts Test the pH of a solution to see if it is acidic or basic. Study why semi-truck drivers use diesel fuel to run their vehicles. Study the energy a quarterback uses to throws a football Examine a marker to determine the individual colors that make up the final color of the marker Examine a hair sample found at a crime scene to test for DNA Study the gases that make up the atmosphere in outer space Study how the muscles contract when a person starts to run Study the rate at which aspirin is dissolved into the human blood system Examine a sample of Doritos chips to see how much dye is in them Examine a sample of cold medicine to understand why it can help suppress the symptoms of a cold

14. The Scientific Method • 1. Observation • 2. Formulate a Hypothesis • 3. Experiment • 4. State the results/theory Tro, Chemistry: A Molecular Approach

15. Observation • Acquiring information or data using your senses. • Some observations are simple descriptions • “The soda pop is a liquid with a brown color and a sweet taste. Bubbles are seen floating up through it.” • Some observations compare a characteristic. • “A 240-mL serving of soda pop contains 27 g of sugar.” Tro's "Introductory Chemistry", Chapter 1

16. Hypothesis • Making an educated guess based on your observations and previous knowledge: • The sweetness of soda pop is due to the presence of • Sugar or • Aluminum Tro's "Introductory Chemistry", Chapter 1

17. Experiments • Test your hypotheses • with a taste test: sugar and aluminum. Theory • State your experimental findings. This is not the same as a scientific law. • Sugar is sweet Tro's "Introductory Chemistry", Chapter 1

18. Example: In the Garden: Each spring 20 seedlings yield 50-60 tomatoes by fall. However, this fall’s yield = 100 tomatoes.

19. Laws • Typically a fact of nature, often a math constant/number and unit. • Law of Conservation of Mass— “In a chemical reaction matter is neither created nor destroyed.” • Speed of Light, E = mc2, Dalton’s Gas Law, Universal Gas Constant, etc… • Unlike California State laws, you cannot choose to violate a scientific law  Tro's "Introductory Chemistry", Chapter 1

20. Theories • Explains how nature behaves. • Newton’s Gravitational Theory: how an apple falls • Dalton’s Atomic Theory: atoms look like… • Darwin’s Theory of Evolution: we always change • Einstein's Theory of Relativity: light is constant • Used to predict future observations. Tro's "Introductory Chemistry", Chapter 1

21. What’s the Difference Between aLaw and a Theory? • Laws: Very specific, “What will happen” often expressed in mathematical equations. • Theories: Very general, “Why it will happen,” often includes many “Laws” Tro's "Introductory Chemistry", Chapter 1

22. Classification of Matter States of Matter Physical and Chemical Properties Physical and Chemical Changes

23. Identify the following as physical (P) or chemical (C) changes. _____1. NaCl (Table Salt) dissolves in water. ______9. Milk sours. _____2. Ag (Silver) tarnishes. ______10. Sugar dissolves in water. _____3. An apple is cut. ______11. Wood rots. _____4. Heat changes H2O to steam. ______12. Pancakes cook. _____5. Baking soda reacts to vinger. ______13. Grass grows. _____6. Fe (Iron) rusts. ______14. A tire is inflated. _____7. Alcohol evaporates . ______15. Food is digested. _____8. Ice melts. ______16. Paper towel absorbs water. Tro, Chemistry: A Molecular Approach

24. Classification of Matter • matter is anything that has mass and occupies space, • Light, music, microwaves are not matter • we can classify matter based on whether it’s solid, liquid, or gas Tro, Chemistry: A Molecular Approach

25. Solids • the particles in a solid are packed close together and are fixed in position • though they may vibrate • the close packing of the particles results in solids being incompressible • the inability of the particles to move around results in solids retaining their shape and volume when placed in a new container, and prevents the particles from flowing Tro, Chemistry: A Molecular Approach

26. Crystalline Solids • some solids have their particles arranged in an orderly geometric pattern – we call these crystalline solids • salt and diamonds Tro, Chemistry: A Molecular Approach

27. Amorphous Solids • some solids have their particles randomly distributed without any long-range pattern – we call these amorphous solids • plastic • glass • charcoal Tro, Chemistry: A Molecular Approach

28. Liquids • the particles in a liquid are closely packed, but they have some ability to move around • the close packing results in liquids being incompressible • but the ability of the particles to move allows liquids to take the shape of their container and to flow – however, they don’t have enough freedom to escape and expand to fill the container Tro, Chemistry: A Molecular Approach

29. Gases • in the gas state, the particles have complete freedom from each other • the particles are constantly flying around, bumping into each other and the container • in the gas state, there is a lot of empty space between the particles • on average Tro, Chemistry: A Molecular Approach

30. Classification of Matterby Composition • matter whose composition does not change from one sample to another is called a pure substance • made of a single type of atom or molecule • because composition is always the same, all samples have the same characteristics • matter whose composition may vary from one sample to another is called a mixture • two or more types of atoms or molecules combined in variable proportions • because composition varies, samples have the different characteristics Tro, Chemistry: A Molecular Approach

31. Classification of Matterby Composition • made of one type of particle • all samples show the same intensive properties • made of multiple types of particles • samples may show different intensive properties Tro, Chemistry: A Molecular Approach

32. Classification of Pure Substances • substances that cannot be broken down into simpler substances by chemical reactions are called elements • basic building blocks of matter • composed of single type of atom • substances that can be decomposed are called compounds • chemical combinations of elements • composed of molecules that contain two or more different kinds of atoms • all molecules of a compound are identical, so all samples of a compound behave the same way • most natural pure substances are compounds Tro, Chemistry: A Molecular Approach

33. Classification of Pure Substances • made of one type of atom (some elements found as multi-atom molecules in nature) • combine together to make compounds • made of one type of molecule, or array of ions • molecules contain 2 or more different kinds of atoms

34. Elements vs. Compounds Na Cl NaCl Tro, Chemistry: A Molecular Approach

35. Classification of Mixtures • homogeneous = mixture that has uniform composition throughout • every piece of a sample has identical characteristics, though another sample with the same components may have different characteristics • atoms or molecules mixed uniformly • heterogeneous = mixture that does not have uniform composition throughout • contains regions within the sample with different characteristics • atoms or molecules not mixed uniformly Tro, Chemistry: A Molecular Approach

36. Classification of Mixtures • made of multiple substances, whose presence can be seen • portions of a sample have different composition and properties • made of multiple substances, but appears to be one substance • all portions of a sample have the same composition and properties

37. Homogeneous vs. Heterogeneous Tro, Chemistry: A Molecular Approach

38. Different Physical Property Technique Boiling Point Distillation State of Matter (solid/liquid/gas) Filtration Adherence to a Surface Chromatography Volatility Evaporation Density Centrifugation & Decanting Separation of Mixtures • separate mixtures based on different physical properties of the components • Physical change Tro, Chemistry: A Molecular Approach

39. Distillation

40. Filtration

41. Problem:You obtain a mixture of iron, sand, and salt. Describe how each substance can be separated using the separation techniques discussed. Youwill use more than one separation technique. You may need to add another substance. Tro, Chemistry: A Molecular Approach

42. Turn in (1 per group) Group Names Title Date Observations Before: Safety: You must wear goggles. Include any other precautions. Procedure: Numbered List. You must be specific Observations After: Conclusions: Successful? Improvements? Tro, Chemistry: A Molecular Approach

43. Physical Changes • Physical change is any change that do • Does NOT result in a change in identity. Examples cutting wire, crushing a solid, gas expanding. • Changes in state of matter is a physical change. Example: melting,boiling, freezing.

44. Physical Properties • Physical properties can be observed or measured without altering the identity of a material. Example: color, texture, melting point, state of matter.

45. Chemical Properties • Chemical Properties relates to a substances ability to undergo changes that alters its identity. • Example a chemical’s reactivity.

46. Chemical Change • Chemical change is when a substance is converted into different substance. • Examples: milk souring, leaves changing color in the fall. • The process CANNOT be reversed.

47. Signs of a Chemical Change • Color Change • Heat and/or light is produced • Bubbles form (gas) • A precipitate is produced (A precipitate is a solid)

48. Energy

49. Energy Changes in Matter • changes in matter, both physical and chemical, result in the matter either gaining or releasing energy • energy is the capacity to do work • work is the action of a force applied across a distance • a force is a push or a pull on an object • electrostatic force is the push or pull on objects that have an electrical charge Tro, Chemistry: A Molecular Approach

50. Energy of Matter • all matter possesses energy • energy is classified as either kinetic or potential • energy can be converted from one form to another • when matter undergoes a chemical or physical change, the amount of energy in the matter changes as well Tro, Chemistry: A Molecular Approach