Fundamentals of Chemistry

1. Fundamentals of Chemistry Chem 1102 Aspects of Chemistry Fall 2008

2. Chemistry • The Central Science • The study of matter • Explains every aspect of daily life • Is essential to understand nearly all scientific, medical and pharmaceutical disciplines, and engineering • A Qualitative Science • Chemistry is based in experimental observation

3. Chemistry • A Quantitative Science • We want to know how many, how much, how good is the measurement • An Experimental Science • A Method of Inquiry • Based on the Scientific Method • An intellectual pursuit • To probe the world around us

4. Scientific Method • Identify a question • Propose a hypothesis • Construct and carry out experiment to test hypothesis • Observe and record results • Refine hypothesis • Test refined hypothesis with more expts (repeat as needed) • Develop theory that is consistent with observations and accepted laws of nature and predicts future exptal outcomes

5. Chemistry in Daily Life • Health care including diagnostics, treatment, medicine, prevention (p. 1, 17, 18, 78, 102, 113, 118, 128, 166, 172, 178, 208, 226) • Food (p. 2, 5, 7, 11, 13, 21, 29, 36, 52, 66, 83, 84, 100, 116, 118, 175, 197, 199, 205 • Environment (p. 46, 50, 105, 107, 122, 145, 180, 195) • Materials around the house (all the rest)

6. Chemistry • Chemistry is the study of matter • Matter has mass and volume • Matter has physical properties • Matter has chemical properties • There are 3 states of matter • And how matter changes • Life of the cell • Production and decay of material • Combustion of fuels

7. Figure 1.16 Organization of Matter (Zumdahl)

8. Atomic Theory of Matter (1808) • John Dalton (1766-1844) • Elements (matter) are composed of atoms • The atoms of a given element are identical. Each element is characterized by the mass of its atoms. • Compounds are formed when atoms of different elements combine with each other.

9. Atomic Theory of Matter (2) • A given compound is a chemical combination of the same atoms in the same relative numbers. • A chemical reaction is the rearrangement of atoms leading to new compounds. Atoms are neither destroyed nor created in a chemical reaction (Conservation of Mass).

10. http://www.rsc.org/chemsoc/timeline//pages/1911.html

11. A Deeper Look into the Atom

12. Figure 2.13 (Zumdahl) (a) Expected Results of the Metal Foil Experiment if Thomson's Model Were Correct (b) Actual Results

13. More on the Atom • An atom is uniquely defined by #p+ = Z = atomic number (see Periodic Table) • In a neutral atom, #p+ = #e-; note that #n is not equal to #p+ nor #e-. • In an atomic ion, #p+ ≠ #e- resulting in a net nonzero charge on the species • Neutral atoms can lose electrons producing a positive ion or cation because #p+ > #e- • Or gain electrons  - ion or anion because #p+ < #e-

14. Isotope • Atoms which have the same Z (same # p+) but a different A (different # n0) • Most elements have isotopes that occur in nature in precise proportions (fractional abundances, %). • A few elements have no naturally occurring isotopes.

15. Figure 2.21 The Periodic Table

16. Periodic Table • An arrangement of elements according to increasing atomic number (Z) which shows the periodic or regularly repeating nature of elemental properties. • Rows = periods • Columns = groups or families • Metals, Nonmetals, Semimetals • Main group (A), Transition Metals, Lanthanides and Actinides

17. http://www.webelements.com/ • http://periodictable.com/ • http://www.uky.edu/Projects/Chemcomics/

18. On to Molecules (n x 106) • Molecules form when atoms are connected by chemical bonds in which electrons act as the “glue” between atoms. • A compound has more than one type of atom bonded together.

19. Chemical Bond Types • IONIC: metal + nonmetal • Electrons are transferred from metal to nonmetal thus creating a cation (+) and anion (-) which attract each other • COVALENT: nonmetal + nonmetal • Electrons are shared by both atoms • METALLIC: metal + metal

20. Chemical Formula • Shorthand symbol for cmps • Qualitative description of the constituent elements in a molecule or ion. • C12H22O11 contains C, H and O • Quantitative description of the relative numbers (subscripts) of atoms of each element. • One molecule of sucrose has 12-C, 22-H and 11-O

21. Chemical Reaction • A chemical rxn is a rearrangement of atoms in which reactant compounds are converted into product compounds. • During a chem rxn, chemical bonds in the reactants are broken and chemical bonds in the products are created. • A rxn is accompanied by a change in energy (i.e. heat can be absorbed or given off), color, state of matter, etc.

22. Chemical Equation • Shorthand symbolic notation for a chemical reaction • CH4(g) + O2 (g)  H2O(ℓ) + CO2(g) • Note that this reaction is NOT BALANCED • Qualitative aspect • identity of reactants [R] and products [P]; use study of nomenclature to write equations • Identify the state of matter for each [R] and [P] • identify reaction type

23. Chemical Equation (2) • Quantitative aspect • how much reactant is consumed and how much product is formed • coefficients must be consistent with the Law of Conservation of Mass; atoms are neither created nor destroyed in a chemical reaction. • i.e. chemical equation must be balanced • CH4(g) + 2O2 (g)  2H2O(ℓ) + CO2(g) Note that this reaction is BALANCED