Basic Chemistry

1. Basic Chemistry

2. Why do we Study Chemistry?

3. Matter and Energy • Matter– anything that occupies space has mass (weight) • Energy – the ability to do work • Chemical Energy- released when bonds are broken (ATP) • Electrical Energy- movement of charged particles • Mechanical Energy- movement of objects (muscles) • Radiant Energy- electromagnetic waves

4. Composition of Matter • Elements • Fundamental units of matter • 96% of the body is made from four elements • Carbon (C) • Hydrogen (H) • Oxygen (O) • Nitrogen (N) • Atoms • Building Blocks of elements

5. Atomic Structure • Nucleus • Protons (p+) • Neutrons (n0) • Outside of nucleus • Electrons (e-) Figure 2.1

6. Identifying Elements • Atomic number • Equal to the number of Protons that the atoms contain • Also equal to the number of Electrons • Atomic mass number • Sum of the Protons and Neutrons • Atomic Symbol

7. Isotopes and Atomic Weight • Isotopes • Have the same number of Protons • Vary in number of Neutrons Figure 2.3

8. Molecules and Compounds • Molecules – two or more atoms combined chemically • Ex: O2, H2O, NaCl, H2 • Compound – two or more different elements combined chemically • Ex: H2O, NaCl, C6H12O6, OH-, CH4

9. Chemical Reactions • Chemical Reaction – When bonds break, atoms rearrange, and new bonds form. • Atoms are united by chemical bonds • Atoms dissociate from other atoms when chemical bonds are broken • Atoms may rearrange, form new bonds, and make a different new molecule

10. Electrons and Bonding • Electrons occupy energy levels called electron shells • Electrons closest to the nucleus are most strongly attracted • Each shell has distinct properties • Number of electrons has an upper limit • Shells closest to nucleus fill first

11. Electrons and Bonding • Bonding involves interactions between electrons in the outer shell (valence shell) • Full valence shells do not form bonds • Inert Elements (Noble Gases) • Nonreactive

12. Inert Elements • Have Complete valence shells and are stable • Shell 1 has 2electrons • Shell 2 has 8electrons • Shell 3 has 8electrons Figure 2.4a

13. Reactive Elements • Valence shells are not full and are unstable • Tend to gain, lose, or share electrons • Allows for bond formation, which produces a stable valence Figure 2.4b

14. Chemical Bonds Ions • Charged particles • Result when atoms gain or lose electrons • Anions are negatively charged • Cations are positively charged • Ionic Bonds • Form when electronsare completely transferred from one atom to another • Opposite charges attract & form ionic bonds PRESS TO PLAY IONIC BONDS ANIMATION

15. Chemical Bonds • Covalent Bonds • Atoms become stable through shared electrons • Single covalent bonds share one pair of electrons • Double covalent bonds share two pairs of electrons • Triple covalent bonds share three pairs of electrons Figure 2.6c

16. Examples of Covalent Bonds PRESS TO PLAY COVALENT BONDS ANIMATION Figure 2.6a–b

17. Polarity • Covalent bondedmolecules • Some are non polar • Electrically neutralas a molecule • Electrons shared equally • Some are Polar • Have a positiveand negative side • Electrons shared unequally Figure 2.7

18. Chemical Bonds • Hydrogen bonds • Weak chemical bonds • Hydrogen is attracted to negative portion of polar molecule • Provides attraction between molecules • Water behaves as a “magnet”, pulling other molecules apart. Thus it is an important solvent.

19. Patterns of Chemical Reactions • Synthesis reaction (A+BAB) • Atoms or molecules combine • Energy is absorbed for bond formation • Endergonic or Anabolic reaction • Growth & Repair. Ex: Amino Acids form proteins, Nucleotides join to form nucleic acids. • Decomposition reaction (ABA+B) • Molecule is broken down • Chemical energy is released • Exergonic or Catabolic reaction • Digestion. Ex: Glycogen  Glucose

20. Synthesis and Decomposition Reactions Figure 2.9a–b

21. Patterns of Chemical Reactions • Exchange reaction (AB + C AC+B) (AB + CD  AD + CB) • Involves both synthesis and decomposition reactions • A switch is made between molecule parts and different molecules are made Figure 2.9c

22. Matter • Matter is classified into 2 categories: • Organic • Inorganic

23. Biochemistry: Essentials for Life • Organic compounds • Contain Carbon and Hydrogen • Most have strong covalent bonds • Large Molecules • Example: C6H12O6 (Glucose) • Inorganic compounds • Lack Carbon • Tend to be simpler & smaller compounds • Example: H2O (Water), NaCL (Salt)

24. Important Inorganic Compounds • Water • Most abundant inorganic compound • (2/3rds of body weight) • Vital properties • High heat capacity • Polarity/Solvent properties • Chemical reactivity • Cushioning

25. Important Inorganic Compounds • Water • High heat capacity: • Prevents temperature changes • Absorbs & transports heat • Polarity/Solvent properties: • Universal solvent • Chemical reactions require water

26. Important Inorganic Compounds • Water • Chemical reactivity: • Hydrolysis- water dissociates & joins larger molecules • Cushioning: • Cerebrospinal fluid- brain, spine • Amniotic fluid- baby • Serous- organs • Synovial- joints • Mucous- membrane linings

27. Important Inorganic Compounds • Salts • Easily dissociate into ions in the presence of water • Ex: NaCl  Na+ + Cl- • Vital to many body functions • Electrolytes: (conduct electrical currents) (release ions in water)

28. Important Inorganic Compounds • Acids • Proton donors *Sour • Release Hydrogen ions (H+) *Corrosive • Electrolytes • Bases *Slippery • Proton acceptors *Bitter • Release OH- (Hydroxide), (Electrolytes) • Neutralization reaction • Acids and bases react to form water and a salt • Ex: HCl + NaOH  H2O + NaCl

29. pH • Measures relative concentration of hydrogen ions • pH 7 = neutral • pH 0 to < 7 = acid • pH > 7 to 14 = base • Buffers: chemicals that can regulate pH change Figure 2.11

30. Important Organic Compounds • Carbohydrates • Contain carbon, hydrogen, and oxygen • Include sugars and starches • Classified according to size • Monosaccharides – simple sugars • Disaccharides – two simple sugars joined by dehydration synthesis • Polysaccharides – long branching chains of linked simple sugars

31. Important Organic Compounds • Lipids • Contain carbon, hydrogen, and oxygen • Carbon and hydrogen outnumber oxygen • Insoluble in water PRESS TO PLAY LIPIDS ANIMATION

32. Lipids • Common lipids in the human body • Neutral fats (triglycerides) • Found in fat deposits • Composed of fatty acids and glycerol • Source of stored energy • Phospholipids • Form cell membranes • Steroids • Include cholesterol, bile salts, vitamin D, and some hormones

33. Important Organic Compounds • Proteins • Made of amino acids • Contain carbon, oxygen, hydrogen, nitrogen, and sometimes sulfur • Account for over half of the body’s organic matter • Provides for construction materials for body tissues • Plays a vital role in cell function • Act as enzymes, hormones, and antibodies

34. Important Organic Compounds • Nucleic Acids • Provide blueprint of life • Nucleotide bases • A = Adenine • G = Guanine • C = Cytosine • T = Thymine • U = Uracil • Make DNA and RNA

35. Important Organic Compounds • Adenosine Triphosphate (ATP) • Chemical energy used by all cells • Energy is released by breaking high energy phosphate bond • ATP is replenished by oxidation of food fuels