Chapter 2 – CHEMISTRY Chapter 3, Sect. 3-1 WATER

1. Chapter 2 – CHEMISTRYChapter 3, Sect. 3-1WATER “…beneath the clothes, we find a man... and beneath the man we find... his... nucleus.”-Nacho Libre

2. BIG IDEAS • The structure and function of all living things are governed by the laws of chemistry. • All organisms are made of matter. • Matter is constantly being rearranged through chemical reactions.

3. Do Now • Respond to the following in your notebook: If we continue to break things apart, eventually, will there be nothing left?

4. Review of Living Things Living things (organisms): -Made of cells -Grow -Reproduce -Have DNA -Use energy -Need food

5. Sect 2-1 Composition of Matter What do living and non-living have in common? All things are made up of matter. • Matter-anything that takes up space and has mass (solids, liquids, gas, plasma).

6. EXAMPLE: On the moon, your mass would be the same! Your weight would be different…less gravity to pull on your mass. Earth weight = 150 lbs Moon weight = 25 lbs Mass = 56g Mass = 56g

7. Elements An element is: • A pure substance that cannot be broken down chemically into simpler kinds of matter. 4 Major elements: • oxygen, • hydrogen, • nitrogen, • carbon Approximately 90% of the mass of living things is made up of these four elements

8. Elements are arranged according to the number of protons they have.

9. Each element has unique chemical symbol • Consists of 1-2 letters • First letter is always capitalized

10. ATOM Atom-Simplest particle of an element that retains all the properties of that element. • Properties of atoms determine the structure and properties of the matter they compose.

11. Atoms are made of: 1. Protons 2. Neutrons 3. Electrons

12. Nucleus-central core of the atom, consisting of protons and neutrons. Electrons are found moving very fast around the nucleus in orbitals (electron cloud/energy levels). • Atoms with no charge (neutral) have equal protons and electrons.

13. DRAW A PICTURE OF AN ATOM (LABEL ALL THE PARTS)

14. Most of an atom is: Empty Space!!!

15. Atomic Number - # of protons in an atom (also tells the # of electrons). Atomic Mass # - number of protons + number of NEUTRONS **LABEL THE DIAGRAM**

16. Compounds A compound is: • Atoms of 2 or more elements chemically joined; the proportion is always fixed. • Also known as a molecule (2 or more atoms chemically joined). Example: H2O, O2, CO2,

17. 2Ways for the elements to combine (BOND): 1. Share electrons 2. Steal electrons Covalent Bond Ionic Bond Salt- the outer electron of Na atom is transferred to the Cl atom ~this results in ions - an atom with a + or – charge. Because + and – attract, this attraction is called an ionic bond.

18. Atoms, Molecules, Compounds Atom of Oxygen Molecules of Oxygen Compound containing Oxygen

19. Do Now In your notebook, respond to the following: On the Periodic Table locate the following elements and give the correct information: Atomic #, Mass, # Neutrons, # Electrons • Fluorine • Neon • Helium

20. Energy It is the flow of energy that the Biologists seek to understand when they study the chemistry of living things…

21. ENERGY Energy in Living Things: As energy flows through a living organism, it is converted from one form to another.

22. ENERGY Atoms and molecules are in constant motion (kinetic energy). Amount of movement determines the state of matter. States of Matter • Solid • Liquid • Gas

23. Solid Liquid • Particles not as tightly linked. • Can flow, conform to the shape of the container. • Definite volume, not definite shape. Example: water • Particles linked together • Has a definite shape • Particles vibrate (little kinetic energy) Example: ice

24. Gas • Particles moving rapidly (lots of energy) • Fill volume of any container. • No fixed volume or shape Example: steam (water vapor) ***To cause a substance to change state, thermal energy (heat) must be added to or removed from a substance***

26. Watch this video on Chemical Reactions at home!

27. Energy & Chemical Reactions Chemical Reaction-breaking or forming chemical bonds. Chemical Equation-represent chemical reactions; reactants are shown on the left, products are shown on the right. • Na + Cl ---- NaCl Reactants Products This chemical reaction is breaking chemical bonds, rearranging and forming new bonds …

29. Water Chapter 3-1 (pgs 49-51) Biology The chemical reactions of life , for the most part, occur in water solutions. ..

30. BIG IDEAS • The chemical reactions of all living things take place in an aqueous environment. • Water’s unique properties make it one of the most important compounds found in living things.

31. DO NOW Respond to the following in your notebook: Which one is more important, food or water?

32. H H Water H O A water molecule (H2O), is made up of three atoms --- one oxygen and two hydrogen.

33. Water is Polar POLAR COMPOUND-a compound where one end is more positively charged while another end is more negatively charged. In each water molecule, the oxygen atom attracts more than its "fair share" of electrons The oxygen end “acts” negative The hydrogen end “acts” positive However, Water is neutral (equal number of e- and p+) --- Zero Net Charge

34. Why is this important? http://programs.northlandcollege.edu/biology/Biology1111/animations/dissolve.html Polarity makes water very good at dissolving things (effective solvent). Water molecules attract other water molecules and solid surfaces.

35. Hydrogen Bonding • Water forms hydrogen bonds with other water molecules. • HYDROGEN BOND-bond between hydrogen of one molecule and the negative region of another molecule. • Causes water to cling to itself and other surfaces: Cohesion and Adhesion

36. Properties of Water

37. Cohesion • COHESION-the same kind of particles being attracted to each other (water sticking to other water). • Results in surface tension- a surface film on water that allows insects to walk on the surface. • Causes water to be a very stable environment.

38. Surface Tension…this water strider cannot generate enough force to break through the hydrogen bonds of the water molecule!

39. Adhesion • ADHESION-water molecules and molecules of solid surfaces are attracted to each other. • EXAMPLE: water sticking to plant leaf

40. Capillarity • Together, adhesion and cohesion enable water molecules to move through narrow tubes against the force of gravity • Capillarity (capillary action)-the ability of water to move through fine pores or up a narrow tube against gravity due to adhesion • Example: the flow of water through its stem

41. A picture of Hydrogen bonds!

42. Adhesion Also Causes Water to … Attach to a silken spider web Form spheres & hold onto plant leaves

43. Capillary action (capillarity) Which gives water the ability to “climb” structures.

44. Water & Homeostasis • Homeostasis - Ability to maintain a steady state despite changing conditions • Water is important to this process because: • a. Makes a good insulator • b. Resists temperature change • c. Universal solvent • d. Coolant • e. Ice protects against temperature extremes (insulates frozen lakes)

45. Section 3-1 Review • On a separate sheet of paper, answer the section review questions 1- 6 in your text on page 51. • All answers should be in complete sentences.

46. Section 2-3 Solutions

47. Mixtures Mixture-substances are combined, but both keep their original chemical properties. • Two Types: • Solutions • Suspensions

48. Solutions Solution-a mixture where one or more substances is evenly distributed in another substance. • Aqueous Solution-water is the solvent • Made of 2 parts: 1. Solute-substance being dissolved in the solution. 2. Solvent-substance in which the solute is dissolved.

49. Solutions

50. Solutions -Concentration-measure of the amount of solute dissolved in a fixed amount of solution. -More solute = greater concentration -Saturated solution-no more solute can be dissolved.