Chapter 2 Chemistry of Life

1. Chapter 2 Chemistry of Life • Can you list the levels of organization?

2. Matter Matter – Anything that has mass and takes up space – made up of atoms. States of matter Solid – has definite shape and volume Liquid – has definite volume, changeable shape Gas – has changeable shape and volume

3. Understanding Basic Chemistry • Atom – the smallest particle into which a substance can be broken by ordinary chemical means. • Parts of an Atom: • Proton – in the nucleus and has a positive charge • Neutron – in the nucleus and has a neutral charge • Electron – in the orbital (shell, energy level) and has a negative charge

4. Atomic Mass = protons + neutrons • Atomic Number = protons • Electrons usually equal the protons if the atom is neutral. • Remember an atom is defined by it’s number of protons. If you change the protons you change the atom!!!!!!!!

5. Valence – number of electrons in the outer energy level. Example 7 • Oxidation Number – number of electrons an atom has gained or lost and the charge associated. Ex. Looking at the above valence of 7 the oxidation number is: -1 • Octet Rule - filling the outer energy level to 8 electrons (exception is the first energy level that can only hold two electrons)

6. Atom- The smallest particle into which a substance can be broken by ordinary chemical means. • Remember an atom has a nucleus that consists of neutrons (neutral) and protons (positive) • Electrons (negative) are found orbiting the nucleus Levels Reviewed

7. Element – Groups of the same type of atom Molecule- Groups of non metal atoms bonded together by covalent bonds & acting as a group. Compound – Two or more elements chemically combined ex. H2O

8. (Organelles- Basic structures within cells – has a specific function) (remember on the line not on a step?) Cell - Basic Unit of living things.

9. Tissue- Tissues are groups of the same cells – they have a common function. Organ- Composed of several different tissues working together.

10. Organ system - A group of organs working together to perform a major body process. Ex. Digestion. Organism- (a group of organ systems in an individual) – any living thing – this would be multicellular (more than one cell)

11. Population - (1 species ex. squirrels) • Community - (2 or more species ex. Squirrels and maple trees) • Ecosystem - (biotic and abiotic - meaning all the living and nonliving things in an area) • Biome - (regional or global area ex. The tundra or a rain forest) • Biosphere - the earth.

12. General Chemistry You Should Remember 

13. Mixtures • Mixtures – two or more substances not chemically combined – therefore they retain their own properties

14. Types of Mixtures: 1. Solutions – evenly combined mixture composed of: • Solvent – does the dissolving ex. Water • Solute – the substance being dissolved ex. Sugar

15. 2. Suspensions –The particles will spread out and eventually settle – large particles (saturated, unsaturated, and supersaturated) • Example sand in water (whole blood) 3. Colloid – a mixture that has medium particles – held in solution by their association with water • ex. Liquid jello….. Mayonnaise

16. Mixtures Compared with Compounds • No chemical bonding takes place in mixtures • Most mixtures can be separated by physical means • Mixtures can be heterogeneous or homogeneous • Compounds cannot be separated by physical means • All compounds are homogeneous

17. Writing Chemical Equations • The left side of an equation is called the reactants. • The right side of an equation is called the products • An arrow separates the reactants from the products. The arrow is called a “yields” sign Ex. Na + Cl  NaCl

18. TYPES OF BONDS(Bonds store energy) IONIC BONDS- ELECTRONS ARE TRANSFERRED FROM ONE ATOM TO ANOTHER AND IONS ARE FORMED Ions are charged atoms resulting from the gain or loss of electrons Anions have gained one or more electrons (taking is negative) Cations have lost one or more electrons (giving is positive)

20. Covalent bonds- when atoms share electrons (the strongest bond) e.x. Peptide bonds – between C and N in proteins

22. Hydrogen bonds- a “bond” between hydrogen and 2 small electronegative atoms ex. f, n, o (the weakest bond – and remember it is really an attraction.

24. Polar and Nonpolar Covalent Molecules Electrons shared equally between atoms produce nonpolar covalent molecules Unequal sharing of electrons produces polar covalent molecules (ex. Water!) (unequal causes a “charge” on each molecule)

25. Types of Reactions • Chemical Reactions – the process of breaking down chemical bonds and/or forming new ones (a chemical equations shows this) • To do this an activation energy is needed ( the energy that is needed to get the reaction going) • Exothermic – there is a net release of energy (it feels warm) • Endothermic – there is a net absorption of energy (feels cool)

26. . Two or more elements or compounds combine to make a more complex substance (ex. Dehydration synthesis – takes H2O away) A + B → AB AB → A + B Compounds break down into simpler substances (ex hydrolysis – puts H2O back) Occurs when one element replaces another one in a compound AB + C → AC + B AB + DC → AC + DB Occurs when different atoms in two different compounds trade places A = Red B = Blue C = Green D = Yellow

27. Additional Vocabulary • 1. Dehydration synthesis (condensation) – the formation of complex molecules by the removal of H2O

28. 2. Anabolism – Energy requiring building phase of metabolism in which simpler substances are combined to form more complex substances

29. 3. Hydrolysis – is an example of a decomposition reaction where water is added back into the molecule

30. 4. Catabolism – Process in which living cells break down substances into simpler substances

31. SUMMARY • The Atomic Number of an atom = • number of • protons in the nucleus. (or electrons in a neutral atom) • The Atomic Mass of an atom = • number of Protons + Neutrons in the nucleus.

32. Remember: • Protons are positive, • Neutrons are neutral • electrons are negative. 4. Protons, Neutrons are in the nucleus and electrons are in the shell.

33. 5. The number of Protons = Number of Electrons in a neutral atom or the atomic number. 6. A “normal” atom has a neutral charge 7. An atom that has given or taken electrons is called an ion (cation gave….. Anion took) 8. An atom that has a different number of neutrons is called an isotope

34. 9. Electrons orbit the nucleus in shells/energy levels/orbitals. 10. Each shell can only carry a set number of electrons

35. 11. Valence – number of electrons in the outer energy level. Example 7 12. Oxidation Number – number of electrons an atom has gained or lost and the charge associated. Ex. Looking at the above valence of 7 the oxidation number is: -1 13. Octet Rule - filling the outer energy level to 8 electrons (exception is the first energy level that can only hold two electrons)