1 Ch. 1: Chemical Foundations · Chemistry: An Overview What is matter made of ?

The Nobel Prize in Physics 1986 L: Heinrich Rohrerb(b1933), R: Gerd Binnig(1947), IBM Zurich Research Laboratory Rüschlikon, Switzerland Scanning Tunneling Microscope (STM)

3 Figure 1.01a: The surface of a single grain of table salt.

4 Figure 1.01b: An oxygen atom on a gallium arsenide surface.

5 Figure 1.01c: Scanning tunneling microscope image showing rows of ring-shaped clusters of benzene molecules on a rhodium surface.

6 Figure 1.2: A charged mercury atom shows up as a tiny white dot.

7 Figure 1.3: Sand on a beach looks uniform from a distance, but up close the irregular sand grains are visible.

8 Oxygen atom, hydrogen atom, water molecule ＊ Substances are made of ~100 atoms

9 Water turning to oxygen and hydrogen

10 Oxygen and hydrogen becoming water

11 Figure 1.4: The fundamental steps of the scientific method.

12 Steps in the Scientific Method 1.Observations  quantitative  qualitative 2.Formulating hypotheses  possible explanation for the observation 3.Performing experiments  gathering new information to decide whether the hypothesis is valid whether the hypothesis is valid

13 Outcomes Over the Long-Term Theory (Model)  A set of tested hypotheses that give an overall explanation of some natural phenomenon. overall explanation of some natural phenomenon. Natural Law  The same observation applies to many different systems different systems  Example - Law of Conservation of Mass

14 Law vs. Theory A law summarizes what happens; A theory (model) is an attempt to explain why it happens.

15 Figure 1.5: The various parts of the scientific method.

However, we tend to see what we expect to see and often fail to notice things that we do not expect. Thus the theory we are testing helps us because it focuses our questions. However, this focusing process may limit our ability to see other possible explanation. It is also important to keep in mind that scientists are human. They have prejudices; they misinterpret data; they become emotionally attached to their theory and thus lose objectivity; and they play politics. Science is affected by profit motives, budgets, fads, wars, and religious beliefs. The scientific methods are only as effective as the humans using them. They do not automatically lead to progress.

17 Nature of Measurement Measurement - quantitative observation consisting of 2 parts Part 1 - number Part 2 - scale (unit) Part 2 - scale (unit)Examples: 20 grams 6.63    Joule seconds

18 International System Based on metric system and units derived from metric system. English System

19 The Fundamental SI Units

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22 Figure 1.6: Measurement of volume 1 liter = 1000 cm 3 = 1000 mL

23 Figure 1.7: Common types of laboratory equipment used to measure liquid volume.

24 Figure 1.8: An electronic analytical balance.

25 Uncertainty in Measurement A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty.

26 Figure 1.9: Measurement of volume using a buret. The volume is read at the bottom of the liquid curve (called the meniscus).

27 Precision and Accuracy Accuracy refers to the agreement of a particular value with the true value. Precision refers to the degree of agreement among several elements of the same quantity.

28 Figure 1.10: The results of several dart throws show the difference between precise and accurate.

29 Types of Error Random Error (Indeterminate Error) - measurement has an equal probability of being high or low. Systematic Error (Determinate Error) - Occurs in the same direction each time (high or low), often resulting from poor technique.

Type of Errors: (1). Determinate (or systematic) error: Can be detected, measured, and eliminated; affect the accuracy of results. 1. Instrument errors-Calibration 2. Method errors -Analysis of standard samples -Independent analysis -Blank determinations -Variation in sample size 3. Personal errors -Care and self-discipline (2). Indeterminate (or random) errors: Cannot predict exactly a results from examination of other results; affect the precision of measurement. -Overall uncertainty.

Precision and Accuracy (exercise 1.2) Volume shown by Volume shown Trial graduated cylinderby the buret mL26.54 mL 2 25 mL26.51 mL 3 25 mL26.60 mL 4 25 mL26.49 mL 5 25 mL26.57 mL Average25 mL26.54 mL Results: Good precision for a graduated cylinder. This graduated cylinder is not very accurate. It has systematic error.

32 Significant Figures and Calculations

33 Rules for Counting Significant Figures - Overview 1.Nonzero integers 2.Zeros  leading zeros  captive zeros  trailing zeros 3.Exact numbers Exact numbers were determined by counting, not obtained from measurement. Exact numbers were determined by counting, not obtained from measurement.

34 Rules for Counting Significant Figures - Details Nonzero integers always count as significant figures has 4 sig figs.

35 Rules for Counting Significant Figures - DetailsZeros  Leading zeros do not count as significant figures has 3 sig figs.

36 Rules for Counting Significant Figures - DetailsZeros  Captive zeros always count as  Captive zeros always count as significant figures has 4 sig figs.

37 Rules for Counting Significant Figures - DetailsZeros  Trailing zeros are significant only  Trailing zeros are significant only if the number contains a decimal point has 4 sig figs.

38 Rules for Counting Significant Figures - Details Exact numbers have an infinite number of significant figures. 1 inch = 2.54 cm, exactly

39 Rules for Significant Figures in Mathematical Operations Multiplication and Division: # sig figs in the result equals the number in the least precise measurement used in the calculation  2.0 =  13 (2 sig figs)

40 Rules for Significant Figures in Mathematical Operations Addition and Subtraction: # sig figs in the result equals the number of decimal places in the least precise measurement =  18.7 (3 sig figs)

41 Dimensional Analysis Proper use of “unit factors” leads to proper units in your answer.

42 Temperature Celsius scale =  C Kelvin scale =  K Fahrenheit scale =  F

43 Temperature

44 Density Density is the mass of substance per unit volume of the substance:

45 Matter: Anything occupying space and having mass.

46 Classification of Matter Three States of Matter: Solid: rigid - fixed volume and shape Liquid: definite volume but assumes the shape of its container Gas: no fixed volume or shape - assumes the shape of its container

47 Figure 1.13: The three states of water (where red spheres represent oxygen atoms and blue spheres represent hydrogen atoms).

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49 Types of Mixtures Mixtures have variable composition. A homogeneous mixture is a solution (for example, vinegar) A heterogeneous mixture is, to the naked eye, clearly not uniform (for example, a bottle of ranch dressing)

50 Figure 1.14: Simple laboratory distillation apparatus.

51 Pure Substances Can be isolated by separation methods:  Chromatography  Filtration  Distillation  Crystalizatiom  Crystalizatiom

52 Element: A substance that cannot be decomposed into simpler substances by chemical means. Compound: A substance with a constant composition that can be broken down into elements by chemical processes.

分離的分類（以物質狀態）： 固體 - 固體混合物： 固體 - 液體混合物： 固體 - 氣體混合物： 液體 - 液體混合物： 氣體 - 氣體混合物： 分離的分類（以方法）： 利用大小的差異：利用薄膜： 利用相的變化：其他分離方法 : 利用化學性親和力： 利用色層分離： 分離科學，楊思廉審定，銀禾文化出版。

54 利用大小的差異： 過濾

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利用大小的差異：

利用相的變化：

利用化學性親和力： （ A ）溶劑 ( 媒）萃取（ like dissolves like ） 液體 - 液體萃取 : 超臨界流體（ Supercritical fluid) 萃取 : de-caffeine, proteins, vitamin Solvent of Green (sustainable) Chemistry (B) 吸附 ( 液體 - 固體、氣體 - 固體）： 吸附劑：活性炭、矽膠、粘土、沸石、陰陽離子交換樹脂

色層分離 (chromatography separation) 移動相固定相方法 氣體固體，液體 GSC, GLC 氣相體色層分離 液體固體，液體 LC 液相色層分離 超臨界流體固體，液體 SFC 超臨界流體色層分離

對掌性異構物 (enantiomers): 具有相同的物性及化性 （乳酸）

對掌性 (Chiral) 的重要性 R form S form R form S form 鎮靜效果 畸胎原 Different biological effect ( 沙利竇邁 )

Taste and absolute configuration of some amino acids Amino acidTaste/enantiomer D-form L-form Asparaginesweettasteless Histidinesweettasteless Isoleucinesweetbitter Leucinesweetbitter Tryptophansweettasteless Tyrosinesweetbitter

Odour of two terpenes Terpene Odour R-(-)-carvonespearmint S-(+)-carvonecaraway R-(+)-limoneneorange S-(-)-limonenelemon