INTRODUCTION and CHAPTER ONE

1. INTRODUCTIONandCHAPTER ONE General Chemistry 200 Read the Introduction and Chapter 1. Chemistry is NOT a spectator sport. Work out complete solutions for all the bold numbered problems.

2. Welcome to the World of Chemistry

3. Beginning Chemistry 200 • Read the book before class! • Study the examples and do the practice exercises. • Be prepared for each class session, lecture and laboratory. • Don’t get behind.

4. Outline for Chapter 1 • Definitions • Homogenous and Heterogeneous • Matter ? • 3 states of matter • Chemical –vs.- Physical Change • Calculations • Density • Temperature • Kelvin  Celsius  Fahrenheit • Fahrenheit  Celsius  Kelvin • Significant Figures (Sig Figs)

5. Matter

6. Mixtures (a)Heterogeneous Cookie (b)Suspension Blood (c)Homogenous Salt water

7. The Language of Chemistry • CHEMICAL ELEMENTS - pure substances that cannot be decomposed by ordinary means to other substances. Aluminum Bromine Sodium

8. The Language of Chemistry • The elements, their names, and their symbols are given on the PERIODIC TABLE • How many elements are there?

9. The Periodic Table Dmitri Mendeleev (1834 - 1907)

10. Sodium Find sodium, Na, on the chart.

11. Copper atoms on silica surface. • An atomis the smallest particle of an element that has the chemical properties of the element. Find copper on the chart.

12. The Atom An atom consists of a nucleus (of protons and neutrons) and electrons in space about the nucleus. Electron cloud Nucleus

13. Thered compound is composed of • Ni- Nickel• C- Carbon• O- Oxygen• N- Nitrogen CHEMICAL COMPOUNDS are composed of atoms and so can be decomposed to those atoms. Fixedcomposition

14. MOLECULE The smallest unit of a compound that retains the chemical characteristics of the compound. MOLECULAR FORMULA Composition of molecules C8H10N4O2- Caffeine H2O

15. The Nature of Matter Chemists are interested in the nature of matter and how this is related to its atoms and molecules. Mercury Hg Gold Au

16. Graphite layer structure of carbon atoms reflects physical properties.

17. Chemistry & Matter • We can explore the MACROSCOPIC world — what we can see — • Understand the PARTICULATE world — we cannot see — We can write SYMBOLS to describe these worlds.

18. A Chemist’s View Macroscopic Particulate Symbolic- 2 H2(g) + O2 (g) --> 2 H2O(g)

20. STATES OF MATTER • SOLIDS — have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement. • Reasonably well understood. • LIQUIDS — have no fixed shape and may not fill a container completely. • Not well understood. • GASES — expand to fill their container. • Good theoretical understanding.

21. THE THREE STATES OF MATTER Bromine (gas) Aluminum (solid) Water or H2O (liquid)

22. KINETIC NATURE OF MATTER Matter consists of atoms and molecules in motion.

23. Physical Properties What are some physical properties? • Color • Melting and boiling point • Odor • Conductivity • Density

24. Physical Changes Some physical changes would be • boiling of a liquid • melting of a solid • dissolving a solid in a liquid to give a homogeneous mixture

25. mass ( g ) = Density 3 volume ( cm ) Gold 19.3 g/cm3 13.6 g/cm3 DENSITY- an important and useful physical property Mercury

26. Which is more dense?

27. Relative Densities of the Elements

28. Sig Figs Sig Fig PPT

29. mass ( g ) = Density 3 volume ( cm ) Problem: A piece of copper has a mass of 57.54 g. It is 9.36 cm long, 7.23 cm wide, and 0.95 mm thick. Calculate density (g/cm3).

30. 1cm 0 95 mm • 0.095 cm3 10 mm 6.4 cm3 = 9.0g/cm3 57.54g . = SOLUTION 1. Get dimensions in common units. 2. Calculate volume in cubic centimeters. 3. Calculate the density. (9.36 cm)(7.23 cm)(0.095 cm) = 6.4 cm3

31. PROBLEM: Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg? In grams? In pounds? Solve the problem usingDIMENSIONAL ANALYSIS.

32. 13.6 g 3 3 95 cm • = 1.3 x 10 g 3 cm PROBLEM: Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg? First, note that1 cm3 = 1 mL Then, use dimensional analysis to calculate mass. See next slide What is the mass in pounds?

33. The milliliter and the cubic centimeter are equivalent. Notice the units of 10’s. back

34. 1 lb 3 1.3 x 10 g • = 2.8 lb 454 g PROBLEM: Mercury (Hg) has a density of 13.6 g/cm3. What is the mass of 95 mL of Hg? What is the mass in pounds? (1 lb = 454 g)

35. PROBLEM: An object weighing 15.67 g is placed in water starting at 6.8 mL, then displaces water to 20.2 mL. What is the density of the object? Density 20.2 6.8 20.2mL - 6.8mL = 13.4mL

36. PROBLEM: An object weighing 15.67 g is placed in water starting at 6.8 mL, then displaces water to 20.2 mL. What is the density of the object? 1 15.67g = 1.17g/cm3 (20.2 - 6.8)ml

37. Chemical Properties and Chemical Change • Burning hydrogen (H2) in oxygen (O2) gives H2O.

38. Chemical Properties • Similar to Physical Properties only with reference to a Chemical reactions • Heat and or light produced • Color • Oder

39. Chemical Properties and Chemical Change • Burning hydrogen (H2) in oxygen (O2) gives H2O. • Chemical change or chemical reaction involves the transformation of one or more atoms or molecules into one or more different molecules.

40. 2 Al + 3 Br2 Chemical Change Al2Br6

41. Electrolyzing water

42. UNITS OF MEASUREMENT • We make QUALITATIVE observations of reactions — changes in color and physical state. • We also make QUANTITATIVEMEASUREMENTS, which involve numbers. • Use SI units — based on the metric system

43. UNITS OF MEASUREMENT Use SI units — based on the metric system length (meter, m) mass (kilogram, kg, and gram, g) time (second)

44. Units of Length • 1 kilometer (km) = ? meters (m) • 1 meter (m) = ? centimeters (cm) • 1 centimeter (cm) = ? millimeter (mm) • 1 nanometer (nm) = 1.0 x 10-9 meter O—H distance = 9.4 x 10-11 m 9.4 x 10-9 cm 0.094 nm 94 pm

45. Measurement • Learn the prefixes in Table 1.4 • Other Relationships 1 cm3= 1 mL = 0.001 L 1.00 lb = 454 g 1.00 in = 2.54 cm 1.06 qt = 1.00 L Significant figuresPage 47 Precision and accuracy Page 43 Examples

46. Temperature Scales • Fahrenheit • Celsius • Kelvin Anders Celsius 1701-1744 Lord Kelvin (William Thomson) 1824-1907

47. Temperature Scales Notice that1 Kelvin degree = 1 degree Celsius

48. Calculations Using Temperature • Generally require temp’s in Kelvin • T (K) = t (°C) + 273 • Body temp = 37 oC + 273 = 310. K • Liquid nitrogen = -196 oC + 273 = 77 K

49. In Class Problems • A rectangular box has dimensions of 20.0 cm15.0 cm8.00 mm. Calculate the volume of the box in liters. • A standard sheet of paper has dimensions of 8.5 inch by 11 inch. A sheet of paper weighs on the average 0.150 g and has a density of 0.710 g/cm3. Calculate the thickness of the paper in cm. • A gallon (3.78 L) of latex paint can cover 385 ft2 of the surface of a wall. What is the average thickness of one coat of paint (in micrometers)?

50. Sample problems • Calculate the volume of 525 g of mercury, d=13.534g/cm3. • The melting point of tin is 505.5 K. Calculate the Celsius temperature. • Find the symbol for gold and the element name for K. • An iron sheet is 3.50 cm square and has a mass of 15.396 g. The density of iron is 7.87 g/cm3. Calculate the thickness of the iron sheet in mm. The End!