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The Chemistry of Life: Carbon and the Nature of Matter

Explore the structure of atoms, the properties of isotopes, the formation of chemical compounds, and the different types of chemical bonds. Learn about the polar nature of water, solutions, suspensions, and the pH scale.

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The Chemistry of Life: Carbon and the Nature of Matter

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  1. Chapter 2 6 C The Chemistry of Life Carbon 12.011

  2. 2-1: The Nature of Matter OBJECTIVES • What three subatomic particles make up atoms? • How are all of the isotopes of an element similar? • What are the two main types of chemical bonds?

  3. Atoms • Atoms are the basic unit of matter • Subatomic particles include protons, neutrons, and electrons • Protons (+) and neutrons (neutral) are in the nucleus and have the same mass • Electrons (-) surround the nucleus and balance out the charge of the protons

  4. Atomic Structure

  5. Elements & Isotopes • Elements consist of only one type of atom • The atomic number is the number of protons • Isotopes are when the same element has different numbers of neutrons • Because they have the same number of electrons, all isotopes of an element have the same chemical properties • Some isotopes are radioactive and can be used to: • Determine the age of rocks and fossils • Treat cancer - Kill bacteria • Trace movements of substances within organisms

  6. Isotopes of Carbon Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 8 neutrons

  7. Chemical Compounds • Chemical compounds are substances formed by the chemical combination of two or more elements in definite proportions • Example: H2O, NaCl • The properties of compounds can be very different from the elements that form them • Example: Sodium and Chlorine

  8. Table Salt is made from Sodium (Explosive when mixed with water) and Chlorine (poison gas) • Table Salt Sodium Chlorine

  9. Sugar Carbon Hydrogen Oxygen

  10. Chemical Bonds • Ionic bonds are formed when one or more electrons are transferred from one atom to another • Ions are atoms with positive or negative charges • Covalent bonds form when electrons are shared between atoms (can be single, double, or triple) • Van der Waals forces are slight attractions that develop between oppositely charged regions or nearby molecules

  11. Ionic Bonding Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1

  12. Ionic Bonding

  13. Covalent Bonding

  14. 2-1 Section Assessment • Describe the structure of an atom. • Why do all isotopes of an atom have the same chemical properties? In what way do isotopes of an element differ? • What is a covalent bond? An ionic bond? • What is a compound. How are compounds related to molecules? • How do van der Waals forces hold molecules together? • How are ionic bonds and van der Walls forces similar? How are they different?

  15. 2-2: Properties of Water • Water is the most abundant compound in most living things • Why are water molecules polar? • What are acidic solutions? • What are basic solutions? OBJECTIVES

  16. The Water Molecule • A water molecule is neutral, however, regions of it have a slight charge • The 8 protons in oxygen pull the electrons away from the hydrogen resulting in a slight – charge near the O and a slight + charge near the H (POLAR) • Hydrogen bonds are weak bonds that form easily in water and give water some special properties: • Cohesion – Attraction between molecules of the same substance • Adhesion – Attraction between molecules of different substances

  17. The Water Molecule

  18. WHITE BOARDS: • Draw a water molecule. Label the Hydrogen and oxygen atoms. Label the “+” and “-” regions.

  19. Solutions & Suspensions • A mixture is a material composed of two or more elements or compounds that are physically (not chemically) combined • Solutions involve the even distribution of components • Solute – The substance that is dissolved • Solvent – The substance in which the solute dissolves • Suspensions are mixtures of water and nondissolved material

  20. Solutions & Suspensions NaCl Dissolving in Water When an ionic compound such as sodium chloride is placed in water, water molecules surround and separate the positive and negative ions.

  21. WHITE BOARDS: • When salt (NaCl) dissolves in water (H2O), salt is the ___________ and water is the ___________.

  22. WHITE BOARDS: • A _______________ is a material composed of two or more elements or compounds that are physically (not chemically) combined.

  23. *Acids, Bases, and pH • The pH scale indicates the concentration of H+ ions in solution • pH scale ranges from 0 (acidic) to 14 (basic) with 7 being neutral (H + = OH-) • Acids form H+ ions in a solution • A base is a compound that produces hydroxide (OH-) ions in a solution (AKA Alkaline)

  24. WHITE BOARDS: • Draw a line (like the one below). Label Acidic, Basic, and Neutral. Place the numbers 0, 7, and 14 on the line.

  25. *Buffers • Maintaining a pH between 6.5 and 7.5 is important for homeostasis • The body controls pH with buffers – weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH

  26. 2-2 Section Assessment • Use the structure of a water molecule to explain why it is polar. • Compare acidic and basic solutions in terms of their H+ and OH- ion concentrations. • What is the difference between a solution and a suspension? • What does pH measure? • The strong acid hydrogen fluoride (HF) can be dissolved in pure water. Will the pH of the solution be greater or less than 7?

  27. 2-3 Carbon Compounds • Organic Chemistry is the study of all compounds that contain bonds between carbon atoms • What are the functions of each group of organic compounds (carbohydrates, lipids, nucleic acids, and proteins)? OBJECTIVES

  28. The Chemistry of Carbon • Carbon has four valence electrons and can form bonds with many elements such as H, O, P, S, and N • Carbon can also bond to other carbon atoms and can form chains that are almost unlimited in length • Carbon can form single, double, or triple covalent bonds, and can even form rings • Carbon is the most versatile element

  29. WHITE BOARDS: • Carbon has four ____________ electrons.

  30. Macromolecules • Macromolecules (giant molecules) are made from thousands or hundreds of thousands of smaller molecules • Macromolecules are formed through the process of polymerization – joining monomers to make polymers • The four groups of organic compounds in living things are carbohydrates, lipids, nucleicacids and proteins (AKA biomolecules)

  31. Polymerization

  32. WHITE BOARDS: • Joining monomers to make polymers is called ______________.

  33. WHITE BOARDS: • Identify the four groups of organic compounds in living things.

  34. Carbohydrates • Carbs contain C, H, and O, usually in a 1:2:1 ratio • Carbs are used as the main source of energy in living things and can be used for structural purposes in plants and some animals • Glucose supplies energy to cells and excess is stored as starch • Monosaccharides – single sugars • Glucose, galactose, and fructose • Polysaccharides – large molecules formed from monosaccharides • Starch, Glycogen (animal starch), and Cellulose

  35. WHITE BOARDS: • Monosaccharides join to make polysaccharides in a process called _______________.

  36. WHITE BOARDS: • What is the ratio of C, H, and O in carbohydrates?

  37. Lipids • Lipids are made mostly from carbon and hydrogen • Lipids are generally not soluble in water • Common categories include fats, oils, waxes, and steroids • Lipids store energy and are an important part of biological membranes and waterproof coverings • Form when glycerol combines with fattyacids • Saturated – fatty acid is filled with H’s • Unsaturated and polyunsaturated – fatty acid has one or more double bonds and is not filled with H’s

  38. Lipids

  39. WHITE BOARDS: • What are the two parts of a lipid?

  40. WHITE BOARDS: • If a fatty acid chain is completely filled with hydrogen, it is said to be _______________.

  41. Nucleic Acids • Nucleic acids contain H, O, N, C, and P • Nucleic acids are made of nucleotides • 5-carbon sugar • Phosphate group • Nitrogen base • Nucleic acids store and transmit hereditary (genetic) information • DNA and RNA are the two kinds of nucleic acids

  42. Nucleotide

  43. WHITE BOARDS: • The three parts of a _____________ are a sugar, a phosphate, and a base.

  44. WHITE BOARDS: • Two kinds of nucleic acids are ______________ and ____________.

  45. Proteins • Proteins contain N, C, H, and O • Proteins are polymers of aminoacids • Amino acids are composed of: • Amino group (-NH2) • Carboxyl group (-COOH) • R-group (different for each) • Proteins control reaction rates, regulate cell processes, form bones and muscles, transport substances, and fight disease

  46. WHITE BOARDS: • A protein is a polymer made of monomers called __________________.

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