Chapter 1 “ Introduction to Chemistry”

1. Chapter 1“Introduction to Chemistry” Charles Page High School Chemistry Stephen L. Cotton

2. Section 1.1Chemistry • OBJECTIVES: • Identify five traditional areas of study in chemistry.

3. Section 1.1Chemistry • OBJECTIVES: • Relate pure chemistry to applied chemistry.

4. Section 1.1Chemistry • OBJECTIVES: • Identify reasons to study chemistry.

5. What is Chemistry? • Chemistry is the study of the composition of “matter” – (matter is anything with mass and occupies space), its composition, properties, and the changes it undergoes. • Has a definite affect on everyday life - taste of foods, grades of gasoline, etc. • Living and nonliving things are made of matter.

6. Chemistry is the study of the composition, structure, and properties of matter and the changes it undergoes – such as burning fuels. C2H5OH+3O2 2 CO2 + 3 H2O + Energy Reactants  Products

7. 5 Major Areas of Chemistry • Analytical Chemistry- concerned with the composition of substances. • Inorganic Chemistry- primarily deals with substances without carbon • Organic Chemistry- essentially all substances containing carbon • Biochemistry- Chemistry of living things • Physical Chemistry- describes the behavior of chemicals (ex. stretching); involves lots of math! Boundaries not firm – they overlap and interact

8. - Page 8

9. What is Chemistry? • Pure chemistry- gathers knowledge for the sake of knowledge • Applied Chemistry- is using chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing – leads to an application * Nylon – Figure 1.3, page 9 * Aspirin (C9H8O4) - to relieve pain * Use of TECHNOLOGY (benefit!)

10. Why Study Chemistry? • Everyone and everything around us involves chemistry – explains our world • What in the world isn’t Chemistry? • Helps you make choices; helps make you a better informed citizen • A possible career for your future • Used to attain a specific goal • What did we describe as “pure” and “applied” chemistry?

11. Why Study Chemistry? • Figure 1.2, page 8 • What benefits do each of the pictures represent in improving our lives? • Give examples in your daily life that involve use of chemistry, and things that do not?

12. Section 1.2Chemistry Far and Wide • OBJECTIVES: • Identify some areas of research affected by chemistry.

13. Section 1.2Chemistry Far and Wide • OBJECTIVES: • Describe some examples of research in chemistry.

14. Section 1.2Chemistry Far and Wide • OBJECTIVES: • Distinguish between macroscopic and microscopic views.

15. Chemistry Far and Wide • Chemists design materials to fit specific needs – velcro (Patented in 1955) on page 12 • perfume, steel, ceramics, plastics, rubber, paints, nonstick cooking utensils, polyester fibers • Two different ways to look at the world: macroscopic and microscopic

16. Chemistry Far and Wide • Energy – we constantly have greater demands • We can conserve it; use wisely • We can try to produce more; oil from soybeans to make biodiesel • fossil fuels, solar, batteries (that store energy – rechargeable?), nuclear (don’t forget pollution!)

17. Chemistry Far and Wide • Medicine and Biotechnology- • Supply materials doctors use to treat patients • vitamin C, penicillin, aspirin (C9H8O4) • materials for artery transplants and hipbones • bacteria producing insulin

18. Chemistry Far and Wide • Agriculture • Produce the world’s food supply • Use chemistry for better productivity – soil, water, weeds • plant growth hormones • ways to protect crops; insecticides • disease resistant plants

19. Chemistry Far and Wide • The Environment • both risks and benefits involved in discoveries • Pollutants need to be 1) identified and 2) prevented • Lead paint was prohibited in 1978; Leaded gasoline? Drinking water? • carbon dioxide, ozone, global warming

20. - Page 16 Let’s examine some information from a graph. 88.2% 440,000 After lead was banned in gasoline and public water supply systems, less lead entered the environment.

21. Chemistry Far and Wide • The Universe • Need to gather data from afar, and analyze matter brought back to Earth • composition of the planets • analyze moon rocks • planet atmospheres • life on other planets?

22. Section 1.3Thinking Like a Scientist • OBJECTIVES: • Describe how Lavoisier transformed chemistry.

23. Section 1.3Thinking Like a Scientist • OBJECTIVES: • Identify three steps in the scientific method.

24. Section 1.3Thinking Like a Scientist • OBJECTIVES: • Explain why collaboration and communication are important in science.

25. Alchemy – developed the tools and techniques for working with chemicals • The word chemistry comes from alchemy – practiced in China and India since 400 B.C. • Alchemy has two sides: • Practical: techniques for working with metals, glass, dyes, etc. • Mystical: concepts like perfection – gold was a perfect metal

26. An Experimental Approach • In the 1500s, a shift started from alchemy to science – King Charles II was a supporter of the sciences • “Royal Society of London for the Promotion of Natural Knowledge” • Encouraged scientists to use more experimental evidence, and not philosophical debates

27. Lavoisier • In the late 1700s, Antoine Lavoisier helped transform chemistry from a science of observation to the science of measurement – still used today • He settled a long-standing debate about burning, which was… • Oxygen was required!

28. The Scientific Method • A logical approach to solving problems or answering questions. • Starts with observation- noting and recording information and facts • hypothesis- a proposed explanation for the observation; must be tested by an experiment

29. Steps in the Scientific Method 1. Observations (uses your senses) a)quantitative involves numbers = 95oF b)qualitative is word description = hot 2. Formulating hypotheses (ideas) - possible explanation for the observation, or “educated” guess 3. Performing experiments (the test) - gathers new information to help decide whether the hypothesis is valid

30. Scientific Method • “controlled” experiment- designed to test the hypothesis • only two possible answers: • hypothesis is right • hypothesis is wrong • We gather data and observations by doing the experiment • Modify hypothesis - repeat the cycle

31. Scientific Method • We deal with variables, or factors that can change. Two types: 1) Manipulated variable (or independent variable) is the one that we change 2) Responding variable (or dependent variable) is the one observed during the experiment • For results to be accepted, the experiment needs to always produce the same result

32. Outcomes over the long term… • Theory (Model) - A set of well-tested hypotheses that give an overall explanation of some natural phenomenon – not able to be proved • Natural Law (or Scientific Law) - The same observation applies to many different systems; summarizes results - an example would be: the Law of Conservation of Mass

33. Law vs. Theory • A law summarizes what has happened. • A theory (model) is an attempt to explain why it happened – this changes as new information is gathered.

34. - Page 22 The procedure that is used to test the hypothesis Using your senses to obtain information Hypothesis is a proposed explanation; should be based on previous knowledge; an “educated” guess Tells what happened A well-tested explanation for the observations; cannot be proven due to new discoveries

35. Collaboration / Communication • When scientists share ideas by collaboration and communication, they increase the likelihood of a successful outcome • Collaboration – Fig. 1.21, p. 24 • How is communication done? • Is the Internet reliable information? • http://www.dhmo.org

36. Section 1.4Problem Solving in Chemistry • OBJECTIVES: • Identify two general steps in problem solving.

37. Section 1.4Problem Solving in Chemistry • OBJECTIVES: • Describe three steps for solving numeric problems.

38. Section 1.4Problem Solving in Chemistry • OBJECTIVES: • Describe two steps for solving conceptual problems.

39. Problem Solving in Chemistry • We are faced with problems each day, and not just in chemistry • A solution (answer) needs to be found • Trial and Error may work sometimes? • But, there is a method to problem solving that works better, and these are skills that no one is born knowing – they need to be learned.

40. Problem Solving in Chemistry • Effective problem solving usually involves two general steps: • Developing a plan • Implementing that plan • The skills you use to solve a word problem in chemistry are NOT different from those techniques used in shopping, cooking, or planning a party.

41. Solving Numeric Problems • Measurements are an important part of chemistry; thus many of our word problems involve use of mathmatics • Word problems are real life problems, and sometimes more information is presented than needed for a solution • Following skills presented will help you become more successful

42. Solving Numeric Problems • The three steps we will use for solving a numeric word problem are: • Analyze • Calculate • Evaluate • The following slides tell the meaning of these three steps in detail. Let’s learn how to ACE these numeric word problems!

43. Solving Numeric Problems • Analyze: this is the starting point • Determine what are the known factors, and write them down on your paper! • Determine what is the unknown. If it is a number, determine the units needed • Plan how to relate these factors- choose an equation; use table or graph • This is the heart of successful problem solving techniques – it is the PLAN

44. Solving Numeric Problems • Calculate:perform the mathematics • If your plan is correct, this is the easiest step. • Calculator used? Do it correctly! • May involve rearranging an equation algebraically; or, doing some conversion of units to some other units.

45. Solving Numeric Problems • Evaluate: – the finishing step • Is it reasonable? Make sense? Do an estimate for the answer, and check your calculations. • Need to round off the answer? • Do you need scientific notation? • Do you have the correct units? • Did you answer the question?

46. Solving Conceptual Problems • Not all word problems in chemistry involve doing calculations • Nonnumeric problems are called conceptual problems – ask you to apply concepts to a new situation • Steps are: • Analyze and 2) Solve • Plan needed to link known to unknown, but no checking units or calculations • Do Conceptual Problem 2.1 on page 46

47. End of Chapter 1 Introduction to Chemistry