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

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

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

Element – Groups of the same type of atom Compound – Two or more elements chemically combined ex. H 2 O

MOLECULE- GROUPS OF ATOMS BONDED TOGETHER & ACTING AS A GROUP ORGANELLES- BASIC STRUCTURES WITHIN CELLS – has a specific function CELL- BASIC UNIT OF LIVING ORGANISMS

TISSUE- TISSUES ARE GROUPS OF CELLS WITH A COMMON FUNCTION. ORGAN- OFTEN LARGE AND COMPOSED OF SEVERAL DIFFERENT TISSUES ORGAN SYSTEM- A GROUP OF ORGANS CARRYING OUT A MAJOR BODY PROCESS ORGANISM- (A GROUP OF ORGAN SYSTEMS IN AN INDIVIDUAL) – any living thing

Mixtures Mixtures – two or more substances not chemically combined – therefore they retain their own properties Solutions – evenly combined Solvent – does the dissolving ex. Water Solute – the substance being dissolved ex. Sugar

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

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

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

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 Cations have lost one or more electrons

COVALENT BONDS- WHEN ATOMS SHARE ELECTRONS (the strongest bond) e.x. Peptide bonds – between C and N in proteins

HYDROGEN BONDS- A BOND BETWEEN HYDROGEN AND 2 SMALL ELECTRONEGATIVE ATOMS ex. F, N, O (the weakest bond)

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

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)

Type of Reaction Definition  Equation Synthesis Decomposition Single Replacement Double Replacement. A = Red B = Blue C = Green D = Yellow A + B → AB AB → A + B AB + C → AC + B AB + CD → AC + BD Two or more elements or compounds combine to make a more complex substance (ex. Dehydration synthesis – takes H2O away) Compounds break down into simpler substances (ex hydrolysis – puts H2O back) Occurs when one element replaces another one in a compound Occurs when different atoms in two different compounds trade places

Identifying Chemical Reactions ____ P + O 2 → P 4 O 10 ____ Mg + O 2 → MgO ____ HgO → Hg + O 2 ____ Al 2 O 3 → Al + O 2 ____ Cl 2 + NaBr → NaCl + Br 2 ____ H 2 + N 2 → NH 3 2. Use colored pencils to circle the common atoms or compounds in each equation to help you determine the type of reaction it illustrates. Use the code below to classify each reaction. S = Synthesis D = Decomposition SR = Single Replacement DR = Double Replacement

____ Na + Br 2 → NaBr ____ CuCl 2 + H 2 S → CuS + HCl ____ HgO + Cl 2 → HgCl + O 2 ____ C + H 2 → CH 4 ____ KClO 3 → KCl + O 2 ____ S 8 + F 2 → SF 6 ____ BaCl 2 + Na 2 SO 4 → NaCl + BaSO 4

Types of Reactions 1. Synthesis – small molecules are combined into larger molecules – always involves the formation of new chemical bonds Ex. A + B  AB

Ex. Dehydration synthesis (condensation) – the formation of complex molecules by the removal of H 2 O A-B-C-H + HO-D-E  A-B-C-D-E + H 2 0

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

2. Decomposition – breaks large molecules into smaller ones AB  A + B –Ex. Food broken down –If water is used to breakdown the bonds then it is called hydrolysis (opposite of dehydration synthesis) Ex A-B-C-D-E + H 2 0  A-B-C-H + HO-D-E

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

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

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