Nuclear Chemistry & Organic Chemistry

1. Nuclear Chemistry & Organic Chemistry

2. Nuclear chemistry • Nucleus of an atom contains protons and neutrons • Strong forces (nuclear force) hold nucleus together • Protons in nucleus have electrostatic repulsion • however, strong force overcomes this repulsion • Strong force: the interaction that binds nucleus together • Nuclear force (strong force) is MUCH stronger than electrostatic force • Strong force increases over short distances

3. Radioisotopes • Radioisotopes- unstable isotopes that gain stability by releasing particles. alpha Unstable isotope stable beta gamma

4. Characteristics of Some Radiation

5. A X Mass Number Element Symbol Z Atomic Number 235 238 U U 92 92 Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutrons Isotopes are atoms of the same element (X) with different numbers of neutrons in their nuclei 2.3

6. Alpha radiation: consists of He nucleus • 23892 U  42 He + 23490 Th • Beta radiation: electrons formed by the decomposition of a neutron • 146 C  0-1 e + 147 N • Gamma radiation: high energy electromagnetic radiation; often emitted with alpha or beta radiation

7. Alpha emission (decay) 4 2 He Identify the product formed when uranium-238 alpha decays 4 2 He +234 90 Th 238 92 U Determines which atom from the periodic table

8. beta emission (decay) 0-1 e Identify the product formed when carbon-14 emits beta particle 0 -1 e + 14 7 N 14 6 C

9. gamma emission (decay) 00 γ Identify the product formed when carbon-14 releases gamma rays 0 0 γ +14 6 C 14 6 C

10. Half-Life 100 g 50 g 25 g • Half-life is the time required for half of a radioactive substance to decay. • 100 g sample has a half-life of 5 years. How much is left after 5 years? • 50 g • How much is left after 1 half-life? • 50 g • How much is left after 2 half-lives? • 25 g

11. N-13 emits beta radiation with a half-life of 10 min. How long is three half lives? • 30 min • How many grams of the isotope will be left if there were 10 g of N-13? • 1.25 g

12. Fission vs. Fusion • Fission: splitting of the nucleus into smaller fragments • Think of the domino effect; atomic bomb • U-235 + slow moving 10 n  smaller atoms + more slow moving 10 n + a lot of energy • Fusion: combining of the nuclei to produce a greater nucleus • Think of the sun; hydrogen bomb • 411 H + 2 0-1 e  42 He + energy

13. What information do the experimental results above reveal about the nucleus of the gold atom? • A The nucleus contains less than half the mass of the atom. • B The nucleus is small and is the densest part of the atom. • C The nucleus contains small positive and negative particles. • D The nucleus is large and occupies most of the atom’s space.

18. Organic Chemistry & Biochemistry Lysozyme – a protein

19. Organic Compounds - Carbon • Organic compounds contain carbon, and most also contain atoms of hydrogen. • They can contain other elements, such as oxygen, nitrogen, sulfur, phosphorus, and the halogens. • The simplest class of organic compounds, hydrocarbons, contain only carbon and hydrogen.

21. Hydrocarbons • Alkanes are hydrocarbons with carbon atoms that are connected only by single bonds.

22. Alkenes are hydrocarbons that contain at least one double bond between two carbon atoms.

23. Alkynes are hydrocarbons that contain at least one triple bond between two carbon atoms.

24. Organic Reactions • Substitution – one or more atoms replace another atom or group of atom in a molecule • Addition – an atom or molecule is added to a molecule

25. Condensation – two or more molecules combine to produce water or another simple molecule • Elimination – simple molecule is removed and a new compound is produced

26. Monomer, Polymer • Polymers are very long organic molecules formed by addition of monomers

27. Carbohydrates There are two types of carbohydrates: The simple sugars Glucose, sucrose, fructose (and many others) The complex carbohydrates. Carbohydrates that are made of long chains of sugars Starches, cellulose

28. Simple Sugars (monosaccharide) All carbohydrates are made up of units of sugar (also called saccharide units). Carbohydrates that contain only one sugar unit are called monosaccharides. Glucose Fructose

29. Simple Sugars - disaccharides Disaccharides have two sugar units bonded together. For example, common table sugar is sucrose (below), a disaccharide that consists of a glucose unit bonded to a fructose unit. 

30. Complex Carbohydrates- polysaccharides Complex carbohydrates are polymers of the simple sugars.  In other words, the complex carbohydrates are long chains of simple sugar units bonded together. For this reason the complex carbohydrates are often referred to as polysaccharides. 

31. Complex Carbohydrates Starch (below) is a polymer of the monosaccharide glucose (n is the number of repeating glucose units and ranges in the 1,000's). Starches and cellulose are complex carbohydrates used by plants for energy storage and structural integrity.

32. Complex Carbohydrates Glycogen, another polymer of glucose, is the polysaccharide used by animals to store energy. Both starch and glycogen are polymers of glucose. Starch is a long, straight chain of glucose units, whereas glycogen is a branched chain of glucose units.

33. Structure of Glycogen

34. Proteins Proteins are polymers of amino acids. Amino acids all have the general structure: The R in the diagram represents a functional group that varies depending on the specific amino acid in question.

35. Twenty amino acids in human metabolism

36. Proteins When 2 amino acids bond together, water is released as the carboxyl end of one amino acid bonds to the amine end of the adjacent one forming a peptide bond, as illustrated at the left. • Because water is lost, the process is called: • Condensation synthesis, or… • Condensation polymerization

37. Proteins When many amino acids bond together to create long chains, the structure is called a protein (it is also called a polypeptide because it contains many peptide bonds).

38. Proteins Proteins are large molecules that may consist of hundreds, or even thousands of amino acids. While there are hundreds of thousands of different proteins that exist in nature, they are all made up of different combinations of amino acids.

39. Insulin

40. Methane - Tetrahedral sp3 Structure • Carbon atoms can form 4 bonds • 4 single bonds = sp3 = tetrahedral

41. Bonding in Ethene & Ethyne • Double bonds = sp2 = trigonal • Triple bonds = sp = linear

42. Carbon • There are four types of solid carbon, 4 allotropes of solid carbon. • Amorphous - coal uninteresting. • Diamond - hardest natural substance on earth, insulates electricity. • Graphite - slippery, conducts electricity. • Fullerenes - look like a soccer ball • How the atoms in these network solids are connected explains why they have different properties.

43. Diamond- each Carbon is sp3hybridized, connected to four other carbons. • Carbon (diamond) atoms are locked into tetrahedral shape. • Strong s bonds give the huge molecule its hardness.

44. Graphite is different. • Each carbon is connected to three other carbons and sp2hybridized. • So, the molecule is flat with 120º angles in fused 6-member rings. • The p bonds extend above and below the plane.

45. This p bond overlap forms a huge p bonding network. • Electrons are free to move through out these delocalized orbitals. • So, the layers slide by each other.

46. Figure 2The Structures of Diamond and Graphite 46

47. Organic Compounds • Contain carbon • Have covalent bonds • Have low melting points • Have low boiling points • Burn in air (oxygen) • Are soluble in nonpolar solvents • Form large molecules

48. Naming Hydrocarbons(nomenclature)

49. Hydrocarbons • Alkanes are hydrocarbons with carbon atoms that are connected only by single bonds.

50. Alkenes are hydrocarbons that contain at least one double bond between two carbon atoms.