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Chapter 2

Chapter 2. Chemistry!. MATTER!. Everything around you is made of matter. Matter is anything that has mass and occupies space. What’s mass again?. Composition of Matter. Elements are one of the simplest chemical substances…can’t break down! 90 occur naturally on Earth

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Chapter 2

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  1. Chapter 2 Chemistry!

  2. MATTER! • Everything around you is made of matter. • Matter is anything that has mass and occupies space. • What’s mass again?

  3. Composition of Matter • Elements are one of the simplest chemical substances…can’t break down! • 90 occur naturally on Earth • 25 essential to organisms • C, H, O, N… • Trace elements-present in small amounts • Iron (Fe), Magnesium (Mg), Zinc (Zn)

  4. Periodic Table • Elements are arranged in the periodic table according to physical and chemical characteristics

  5. Atoms: Building Blocks • Atoms are the smallest particles of elements that have that element’s characteristics • Review of Atomic Structure • Nucleus- • Protons- (p+) • Neutrons- (n0)

  6. Electrons and Energy Levels • Electrons form a cloud around nucleus • Travel in specific regions called energy levels. • Levels have limited capacities: • Level 1-Hold max. of 2 e- • Level 2-Hold max. of 8 e- • Level 3-Hold max. of 18 e- • Elements are stable when outer level is full

  7. Bohr Energy Level Diagrams

  8. Isotopes of Elements • Isotopes are atoms of the same element that have different numbers of neutrons. • Most Carbon contain 6 neutrons…. • Others have 7 and 8…they are isotopes of the element carbon • Referred to as C-12, C-13 and C-14 • Some are unstable-used for radiation therapy

  9. Interactions of Matter • A compound is a substance that is composed of atoms of different elements chemically combined. • Chemical reactions happen when atoms are rearranged and new bonds are formed • Compounds important to us??

  10. Bonding • Covalent Bond- two atoms sharing electrons to hold together • Hydrogen Stability • Molecules are groups of atoms held together by covalent bonds with no charge • Molecules are the simplest form of a substance that retains its properties freely

  11. Water Molecule

  12. Ionic Bonds • An atom that gains or loses electrons has an electrical charge and is called an ion. • Elements will give up/take electrons to fill outer shells • The attractive force between two opposite charged ions is an ionic bond.

  13. Ionic Bonds

  14. Section 2.2- ENERGY • Energy is defined as the ability to do work or cause change. • NRG can be in various forms and can transfer forms. • Free Energy is the NRG in a system available for work. • In cells, it’s the NRG to fuel cell processes • NRG can also change states of matter….

  15. States of Matter • Atoms in a substance are actually in constant motion. • The rate at which atoms or molecules move determines the state.

  16. Three Major States • SOLIDS: • DEFINITE VOLUME • DEFINITE SHAPE • LIQUIDS: • DEFINITE VOLUME • NO DEFINITE SHAPE (Containers’ shape) • GASES: • NO DEFINITE VOLUME • NO DEFINITE SHAPE

  17. NRG & Chemical Reactions • Metabolism is all of the chemical reactions occurring within an organism. • Reactions break down/build up molecules important to function. • Written in chemical equations using symbols and formulas.

  18. What process is this?

  19. Breakdown of RXNs • Reactants are on the left side of the equation. • Products are on the right side of the equation. • Reactant bonds are broken, atoms are rearranged, and new bonds form to make products!!

  20. Coefficients vs Subscripts • Coefficients- Big numbers before an element or compound. • Tell you how many molecules you have! • Ex.- 6CO2 means six molecules of CO2 • Subscripts- Small numbers after an element. • Tell you how many atoms you have! • Ex. – H2O means 2 atoms of H.

  21. NRG TRANSFER • Chemical reactions that involve a net release of NRG are known as exergonic. • Chemical reactions that involve a net absorption of NRG are known as endergonic. • Catalysts speed up reactions by lowering the activation NRG, or NRG needed to start the reaction.

  22. Role of Catalyst:

  23. Mixtures vs Solutions • A mixture is a combination of substances in which they retain their own properties. • Sand & Water • Solutions are mixtures in which one or more substances distribute evenly in another substance • Kool-Aid!!

  24. Solutions • Solutes are the substances dissolved in solutions. • Solvents are the substances in which the solute is dissolved. • Concentration is determined by the amount of solute dissolved in a fixed amount of solution. • If no more solute can be dissolved, the solution becomes saturated.

  25. Acids and Bases • Water molecules can be broken down into two oppositely charged ions in a process called dissociation.

  26. Acid vs Base • pH measures how acidic or alkaline (basic) a solution is. • Acid is any substance that has more hydronium ions (H3O+) in water. pH<7 • Base is any substance that has more hydroxide ions (OH-) in water. pH>7

  27. Acid/Base Characteristics • ACIDS: • Sour Taste • Can be corrosive • Examples: • BASES: • Bitter Taste • Feel slippery • Examples:

  28. Strength of Acids/Bases • Strength is based on distance from neutral, or pH of 7. • Ex. #1- A base with a pH of 13 is stronger than a base with pH of 8. • Ex. #2- An acid with a pH of 1 is stronger than an acid with a pH of 5.

  29. pH Scale • pH Scale is based on logarithmic scale. • Change in unit equals ten times the change in alkalinity or acidity. • Ex.- pH 2 is ten times stronger than pH 3.

  30. pH Scale

  31. BUFFERS!! • Living organisms are very sensitive to pH changes. • pH in organisms is controlled by buffers • Buffers can neutralize small amounts of acids or bases in a solution

  32. APE MAN!! • ATOMIC # = # Protons = # Electrons • Ex- Boron has atomic # 5 • Boron has 5 protons and 5 electrons!!

  33. MORE APE MAN!! • MASS # - ATOMIC # = # Neutrons • Ex.- Cobalt has: • Mass # = 59 • Atomic # = 27 • 59 – 27 = 32 Neutrons!

  34. Water’s Uniqueness • 1. Water is polar-it has an unequal distribution of charge. • Two Hydrogens=Positive End • Oxygen=Negative End • Molecules attract to each other and to ions • Ability to dissolve other polar substances…

  35. Hydrogen Bonding • 2. Hydrogen Bonding-the attraction of opposite charges of H and O. • Important for holding together large molecules: Proteins! • Also can occur between hydrogen and most electronegative atom in another polar molecule!

  36. Hydrogen Bonds

  37. Cohesion • 3. Cohesion is the attraction between particles of the same substance. • Creates high surface tension • Floating organisms • Beading on leaves

  38. How’d he do that?

  39. Adhesion • 4. Adhesion is the attraction between two different substances. • Allows water to creep up thin tubes: capillary action • Plants getting water from ground

  40. Specific Heat/Vaporization • 5. Water has a high specific heat. • Amount of heat NRG needed to raise/lower 1g of a substance by 1 degree Celsius. • Takes a lot to go from 0 (freezing) to 100 (boiling)! • Also has high heat of vaporization. • NRG needed to convert 1g of a liquid to gas! • Water resists temperature change. • Buffer for temperature-limits extremes

  41. Density • 6. Water expands when freezing. • Ice less dense than water!! • Lakes and Ponds…

  42. What if…..

  43. Water and Homeostasis? • What’s that word again? • How does water help?

  44. 7.3- Life Substances • Organic molecules contain carbon. • Carbon forms single, double or triple bond.

  45. Organic molecules have great variety… • Formulas for compounds may be the same but differ in structure- isomers • Also vary in size! • A polymer is a large molecule formed from bonding of smaller molecules…usually in long chains

  46. Carbohydrates • Organic compounds composed of C, H and O. • Monosaccharides-simplest type • Disaccharides-two monosaccharides • Polysaccharides-many mono. units

  47. Polysaccharides • Starch-chains of glucose used as food storage by plants • Glycogen-food storage by animals • Cellulose-cell wall and structural support for plants

  48. Lipids • Organic compounds with large proportion of C-H bonds • Commonly known as fats and oils • Insoluble in water • Composed of fatty acid chains attached to a glycerol • Used for energy storage, insulation and protection

  49. Saturated vs Unsaturated • Saturated • 1. Chains of Carbon single bonded • 2. Generally solid at room temperature • Unsaturated • 1. Chains of Carbon double bonded • 2. Generally liquid at room temperature

  50. Proteins • Large, complex polymer composed of C, H, O, N, and sometimes S. • Building Blocks=Amino Acids • 20 common AA’s • Linked by condensation-removal of -H and -OH groups to form water. Resulting covalent bond is called a peptide bond

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