Sections 1.1 and 1.2. Speaking the language Science and the scientific process Forces Matter. Sections 1.3 and 1.4. Representations of matter Scale

Transcription

1 Introduction

2 Chapter 1 The Study of Chemistry (1.1) The Scientific Method (1.2) Classifications of Matter (1.3) Physical and Chemical Properties of Matter (1.4) Measurement (1.5) Handling Numbers (1.6) Dimensional Analysis in Solving Problems (1.7)

3 Outline Overall Concepts Sections 1.1 and 1.2 Speaking the language Science and the scientific process Forces Matter Sections 1.3 and 1.4 Representations of matter Scale Sections Measurements and units

4 Overall Concepts Science and the scientific process Definition: Theory Speaking the language Definitions Equations Representations Formula Definition: Matter Definition: Force Figure 1.1, p. 3

5 1.3 Representations H 2 O(g) H 2 O(l) H 2 O(s) Figure 1.2, p. 4

6 1.3 Classification of Matter Figure 1.5, p. 7

7 1.4 Physical and Chemical Properties of Matter Physical property Chemical property Intensive property Extensive property Macroscopic property Microscopic property

8 1.3 Representations H 2 O(g) H 2 O(l) H 2 O(s) Figure 1.2, p. 4

9 Scale: What is scale? Scale is a slippery concept, one that is sometimes easy to define but often difficult to grasp... there is much equivocation about scale, as it is at the same time a concept, a lived experience and an analytical framework (p. 1). Lock G. & Molyneaux B. (Eds.), (2006). Confronting scale in archeology. NY: Springer.

10 Scale: What is scale? Understanding and applying scale involves a number of concepts and processes such as quantity, distance, measurement, estimation, proportion, and perspective. Although most applications of scale involve linear distances, other variables such as temperature, time, volume, or mass are also important. A broad definition of scale can be any quantification of a property that is measured. Or any quantification of a property of size that is measured. Jones, M.G. and Taylor, A.R. (2009) Journal of Research in Science Teaching, 46,

11 Science Literacy Why should I care about scale? What goes into science literacy? Scale Workshop According the National Research Council (NRC) of the National Academies of Science, Board on Science Education: Patterns Cause and effect: Mechanism and explanation Scale, proportion, and quantity Systems and system models Energy and matter: Flows, cycles, and conservation Structure and function Stability and change National Research Council, Board on Science Education, Division of Behavioral and Social Sciences and Education (2011) A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas, National Academies Press, Washington, D.C This work is supported by the National Science Foundation [NSF (DUE )]

12 Scale: Why should we care about it? Experts in their fields cited scale as critical to their ability to be successful in their careers. Who are these experts? Jones, M.G. and Taylor, A.R. (2009) Journal of Research in Science Teaching, 46,

13 Scale: Why should we care about it? Experts in their fields cited scale as critical to their ability to be successful in their careers. What did they say on the importance of scale? Jones, M.G. and Taylor, A.R. (2009) Journal of Research in Science Teaching, 46,

14 Oh well, everything has to do with scale. I d say it s critical I think it s critical to understand scale. It s absolutely one of the first things that we do. I mean obviously it is very important. It comes in at so many different levels, each one of them have scales within it, scales not just the fact that I am looking at something small It s key. I mean in chemistry it is key. Again because we are living in a microscopic world and all the things that are composed are microscopic Extremely!! It s a pretty big part of it. It has now become second nature I probably wouldn t be able to do it if I didn t understand scale. Extremely important It s very important to my job because if I m not accurate with my scale, or the information I get isn t accurate, it can completely throw off all of my results

15 Scale: What does scale involve? This begins with: Visual spatial skills Making measurements Measurement and estimation

16 1.3 Representations H 2 O(g) H 2 O(l) H 2 O(s) Figure 1.2, p. 4

17 Scale: What does scale involve? This extends into: Creating reliable scales Visualizing scales Relating scales Converting Number sense

18 1.3 Representations H 2 O(g) H 2 O(l) H 2 O(s) Figure 1.2, p. 4

19 Scale: What does scale involve? This completes with: Applying conceptual anchors Unitizing to self Understanding relative sizes Understanding different scales

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29 1.5 Measurement Table 1.3, p. 10

30 1.5 Measurement Figure 1.6 p. 9

31 1.5 Measurement Figure 1.6 p. 9

32 1.5 Measurement Table 1.2, p. 9

33 1.5 Measurement Figure 1.7 p. 10 Figure 1.6 p. 9

34 1.5 Measurement Table 1.4, p. 11 Margin figure, p. 11

35 1.5 Measurement Figure 1.8, p. 12

36 1.6 Scientific Notation Make sure you are comfortable with the rules associated with converting between scientific and standard decimal notation as well as rules for exponents when using mathematical operations.

37 1.6 Significant Figures Make sure you are comfortable with the rules associated with determining the number of significant figures in a value and preserving the correct number of significant figures when using mathematical operations.

38 1.7 Dimensional Analysis in Problem Solving Remember equivalencies and the rules governing these check yourself while you have the anchor of understanding the problem (unit conversions) so you can be more confident when you are in the abstract. It will not always help you.

39 1.7 Dimensional Analysis in Problem Solving 1. Identify the problem (read the problem) you will have to determine what you need to do. 2. Identify what you are given and what you need. 3. Determine how to set up your solution (with a picture this may be easier). 4. Calculate or determine your answer. 5. Report your answer. Remember units and significant figures. 6. Check your answer. Did you answer the question and (most importantly) does your answer make sense and is it reasonable?

40 Practice Example #25: Convert to meters order by size 100 nm 0.01 cm 10 mm 0.10 km 10 m 0.01 μm 100 pm 0.01 nm

41 Practice Example #26: Comparisons of size, part 1 What would a person look like next to the picture below?

42 Practice Example #27: Comparisons of size, part 2 What is one object that would be visible on the earth from space?

43 Practice Example #28: Comparisons of size, part 3 What would a water molecule look like in relation to a virus?

44 Practice Example #29: Comparisons of size, part 4 What would a water molecule look like in relation to a bacterium?

45 Practice Example #30: Comparisons of size, part 5 What would a water molecule look like in relation to a cell?

46 Practice Example #31: Comparisons of size, part 6 What would a water molecule look like in relation to a sugar crystal?

47 Practice Example #32: Comparisons of size, part 7 Revisit this comparison of a water molecule in relation to a cell and consider Figure (p. 457) This is described as A cell in an isotonic solution What is wrong with this picture?

48 Practice Example #33: Using cubic units and unit conversions One gallon of paint is used to paint the walls and ceiling of a room with no windows (or door). The room measures 12 feet by 12 feet (cube). What is the thickness in μm of the (wet) paint? (1 in = 2.54 cm; 1 qt = L; 4 qt = 1 gallon)

49 Examples from past exams If the original volume of the liquid in the graduated cylinder was ml and the metal has a mass of 31.4 g, what is the density of the metal (in g cm 3 )? A. 1.1 g cm 3 B. 1.3 g cm 3 C. 7.9 g cm 3 D. 9.0 g cm 3

50 Examples from past exams A reaction between carbon monoxide and oxygen occurs as shown in the particulate drawing. This is an example of a A. chemical change with a product that is a compound. B. chemical change with a product that is a mixture. C. physical change with a product that is a compound. D. physical change with a product that is a mixture.