Chemistry

1. Composition of Matter Energy Solutions Chemistry

2. Composition of Matter • Why discuss chemistry in biology class? • The structure and function of all living things are governed by the laws of chemistry

3. Matter • Makes up everything in the universe • Anything that occupies space and has mass • Mass is not = to weight • Weight is the pull of gravity on an object (mass would not change because it is the “quantity of matter” an object has… • You would still be the same “being” on Earth and on the moon = your mass doesn’t change…HOWEVER…your weight would be significantly less on the moon due to the pull of gravity

4. Chemical changes in matter • Essential to all life processes • Living things are made up of the same kinds of matter that make up nonliving things • Understanding changes in matter = understanding of life processes of organisms

5. Elements • Pure substances that cannot be broken down chemically into simpler kinds of matter • 90% of mass of all kinds of living things is composed of combinations of 4 elements: • Oxygen (O) • Carbon (C) • Hydrogen (H) • Nitrogen (N)

6. Chemical Symbols Atomic Number Chemical Symbol Atomic Mass Name

7. Atoms • Simplest particle of an element that retains all of the properties of that element • Nucleus = core of atom • Made of protons (+) and Neutrons (no charge) • All atoms of a given element have same # of protons • Atomic # = number of protons • Electrons • High energy particles; negatively charged; move about nucleus at very high speeds in “energy levels” • First e- level = up to 2 e- • Second e- level = up to 8 e-

8. AtomicEnergyLevels

9. Compounds • Under natural conditions, most elements do not exist by themselves • A compound is a pure substance that is made up of atoms of two or more elements that are fixed = water: H2O = chemical formula indicates that the atoms always combine in a proportion of two Hydrogen atoms to one Oxygen atom

10. Making Compounds • Stable atom = outermost energy level is filled • Most atoms are not stable in natural state = meaning they tend to react/combine with other atoms in order to achieve stability • Undergo chemical rxns to achieve stability = chemical bonds are broken; atoms are rearranged; new bonds are made

11. Bonds • Covalent = 2 atoms share one or more pairs of e- • Ionic= one e- gets transferred from one atom to another, resulting in more stability and giving both atoms a charge of + or -

12. You payin’ attention????

13. What are you to do now? • You are going to complete a “Guided Notes” (GN) activity… On page 35 of your textbook, you will notice that there are 4 objectives listed. Make a chart/table using the objectives and take notes from the reading. Ex: Objective Notes

14. Back to our notes!!!!!

15. Energy - E • Energy is the ability to do work • Biological systems need/use: chemical energy, thermal energy, electrical energy, and mechanical energy • Free energy = energy available for work (cell processes would benefit from this)

16. Do Right this Very Minute (DRTVM) • Two Truths and a Lie…. • Take an index card from the front desk • From the homework (a few nights ago), write down two truths and a lie about “Energy” • You have 2 minutes! • When 2 minutes are up…you are to find 3 people NOT at your table and try to trick them… • Write down all 3 names on the other side of your card and write down if they picked the lie or not… • You have 5 minutes!

17. States of Matter • Solid, liquid, or gas • Atoms in constant motion…their speed determines the state… • Solid = particles are tightly linked in definite shape (fixed volume and shape) • Liquid = particles are not as tightly linked (fixed volume) • Gas = particles move most rapidly; move freely; little or no attraction to each other *Thermal energy must be added to change a state

18. Energy and Chemical RXNs

19. Chemical Rxns • Our bodies need a lot of energy…we get it from breaking down sugars from food into CO2 and H2O • Exergonic = chem. rxn where E is released • Endergonic = chem. rxn where E is absorbed

20. Activation E • What gets you up and moving faster???

21. Really…activation E • the amt of E needed to start a rxn • Catalysts lower the amt of activation E necessary for rxn • Enzymes are important catalysts to living things – specific to individual chemical rxns

22. E movement • Constant flow of energy into and throughout living things • Many involve transfer of e- between atoms

23. Redox Reactions – These work together When a compound becomes “oxidized” it loses its electrons to another compound… When a compound gains electrons, it becomes negatively charged, or reduced.

24. Solutions (solns) • Solution (soln) – 1+ substances are = distributed in another substance • Solute – dissolved substance • Solvent – does the dissolving (water is the universal solvent) • Concentration – measurement of amt of solute dissolved in a fixed amt of soln • Saturated soln – no more solute can dissolve • Aqueous soln – water is solvent

25. Dissociation of H2O • Breaking apart of water

26. Acids and Bases When an acid is introduced into a neutral solution, it adds H+ ions When a base is introduced into a neutral solution, it adds OH- ions

27. pH • Scale developed to compare the relative concentration of hydronium ions and hydroxide ions in a solution • Ranges from 0 to 14 • 0 = very acidic • 14 = very basic • 7 = neutral (water) See Figure 2-10 on page 42

28. BuffersDefinitely NOT this guy! • Chemical substances that neutralize small amts of either an acid or a base added to a soln