Chemistry for Living Things

Composition of Matter Matter – anything that takes up, or occupies space….and has mass! Mass – amount of matter in an object ARE Mass and Weight the same????

Most Common Elements in Living Organisms Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) 90% of living things are made of these 4 Elements

What Are Atoms? Smallest particles that keep properties of an element. Two parts: Energy rings and nucleus (center) Made up of 3 subatomic particles: Protons (+)  found in the nucleus Electrons (-)  found in the energy rings around the nucleus, repel one another, attracted to the protons Neutrons (no charge)  found in nucleus Must have equal number of protons and electrons Must remain electrically stable

C 12.011 6 atomic number # of protons or electrons element symbol and name atomic mass # of protons + # of neutrons 12.011 Round to make it a whole number

Na K Cl 1) 2) 3) ------Atomic # ------Atomic # ------Atomic # 11 ------- Element -------Atomic mass aka Mass # 11 Sodium 22.93~ 23 1) Na How many Electrons? How many Protons? How many neutrons? 11 23= N + 11 N= 12 ------Atomic # ------- Element -------Atomic mass aka Mass # 19 Potassium 39.098~ 39 K 2) How many Electrons? How many Protons? How many neutrons? 19 19 39= N + 19 N= 20 ------Atomic # ------- Element -------Atomic mass aka Mass # 3) 17 Chlorine 35.453~ 35 Cl How many Electrons? How many Protons? How many neutrons? 17 17 35=N+17 N=18

Energy Levels – what is the max # electrons in each level? An element is stable if energy level is completely filled with electrons…it is happy….if not completely filled it is mad and will want to react 8 is the happy number, except for hydrogen and helium which want 2 If not 8, considered unstable and will react 2 8 8

BOHR MODEL PEN write down the numbers of each Draw nucleus with the P and N Draw Energy levels around nucleus until you used all your electrons… remember 2, 8, 8

Show a Bohr Model for: Carbon (#6, mass12) Sodium (#11, mass 22.9) Oxygen (#8, mass 15.99)

F Lewis Dot Diagrams ___P ___N Represent the element by the chemical symbol and a “dot” for each valence electron. F 9e 9 F 19 9 ___P ___N 10 electron Symbol for fluorine

OPEN NOTES QUIZ!!! Elements 1)___________ are substances that cannot be broken down into simpler substances. 2) Atoms are composed of _______, _______, & ________. 3) Atoms achieve stability when their ________energy level is filled with ______ electrons. 4) A _____________ bond is formed when two atoms share electrons. 5) An __________bond is formed when one atom donates or gives up an electron. 6) What is located in the nucleus of an atom? 7) How many Protons does SILICON have? How many electrons in its outer ring? Protons electrons neutrons Outer 8 Covalent ionic Protons and neutrons

Chemical Bonds, Molecules, & Compounds Bond is union between electrons Atoms bond to form molecules Molecules of compounds contain more than one element - H2O

Ionic Bonding when you: ION a charged particle If atom loses __________ electrons, becomes positively charged ion _____________ these electrons, becomes negatively charged ion Charge difference attracts the two ions to each other Ever hear the phrase “Opposites Attract”…… Not a strong bond One atom gives and the other recieves If atom gains

Formation of NaCl Na + Cl  NaCl Sodium atom (Na) Chlorine atom (Cl) Outer shell has one electron Chlorine atom (Cl) Outer shell has seven electrons Na transfers electron to Cl forming Na+ and Cl- Na + Cl  NaCl

Covalent Bonding Atoms share a pair or pairs of electrons to fill outermost shell wants 8 remember Sharing is Caring Strong bonds Water is held together by a covalent bond O + O  O2

Chemical Bookkeeping Reactants  Products Yeilds OH + H  H2O

Try this one>>>>> hahaha Na + O + H  NaOH

Energy and Chemical Reactions Energy is absorbed or released when chemical bonds are broken and new ones are formed. For most chemical reactions to begin, activation energy must be added to the reactants Catalysts /ENZYMES are proteins that reduce the amount of activation energy needed to begin a reaction.

Solutions = Solute + Solvent A mixture in which one or more substances are uniformly distributed in another substance Made up of: SOLUTE – substance ___________________ the solution SOLVENT – substance in which the __________________________________ dissolved in solute is dissolved in

Concentration amount of solute dissolved in a solution (High or Low) Concentration= mg/mL

0---------------------7-------------------14 The pH Scale H+ Measures ______ concentration of fluid Highest H+ Lowest H+ 0---------------------7-------------------14 Acidic Neutral Basic More H3O+ = More OH- Hydronium Hydroxide

Examples of pH Pure water is neutral with pH of 7.0 Acidic Basic Stomach acid: pH 1.0 - 3.0 Lemon juice: pH 2.3 Basic Seawater: pH 7.8 - 8.3 Baking soda: pH 9.0

Buffer Systems Minimize shifts in pH Partnership between weak acid and base it forms when dissolved Two work as pair to counter shifts in pH Jelly fish stings are basic.

3.1 WATER

what causes these charges? Structure of WATER 2 1 ___ Hydrogens, ___ Oxygen (Polar) Covalent Bond O has a slightly negative (-) charge H have a slightly positive (+) charge what causes these charges?

Polarity – uneven charge When the # of protons in two nuclei is NOT the same, ____________ spend more time near nucleus with most protons Water - electrons more attracted to ____ nucleus than to _____ nuclei Electrons O H

6P

Weak Hydrogen bonds hold Liquid Water together + + _ H + O H + O _ + H +

Hydrogen Bonding - the force of attraction between: a Hydrogen with a + charge AND another atom/molecule with a - charge - H bonds form, break and reform with great frequency and ease (weak bonds)

Hydrogen Bonding holds DNA strands together

Atom in one polar covalent molecule can be attracted to oppositely charged atom in another such molecule UNIVERSAL SOLVENT

Spheres of Hydration Na+ Cl– – + Fig. 2.16, p. 29

Polarity Temperature-Stabilizing Cohesive Solvent Makes Ions Properties of Water Polarity Temperature-Stabilizing Cohesive Solvent Makes Ions

Water Is a Polar Covalent Molecule Molecule has no net charge Oxygen end has a slight negative charge Hydrogen end has a slight positive charge O H H

Temperature-Stabilizing Effects absorb a lot of heat Liquid water can _____________________ before its temperature rises Why? Much of the added energy disrupts hydrogen bonding rather than increasing the movement of molecules

Water Is a Good Solvent Ions and polar molecules dissolve easily in water When solute dissolves, water molecules cluster around its ions or molecules and keep them separated

Hydrophilic & Hydrophobic Substances Hydrophilic substances Polar Hydrogen bond with water Example: sugar, salt Hydrophobic substances Nonpolar Repelled by water Example: oil

Water Cohesion/Adhesion Hydrogen bonding holds molecules in liquid water together (cohesion) and also attracts to other surfaces (adhesion) Creates tension surface

cohesion water sticks to water

water sticks to something else adhesion water sticks to something else

Explains how water defies gravity and travels upwards in plant stems Explains how water defies gravity and travels upwards in plant stems! Moving up through narrow tubes against the force of gravity is called _______________ capillarity

Why Ice Floats In ice, hydrogen bonds lock molecules in a ________________________ (spread out solid formation) Water molecules in lattice are spaced farther apart then those in liquid water Ice is _____________ dense than water l a t t i c e less

1. Describe the structure of a water molecule 2. How does polar differ from nonpolar? 3. what happens when ions are mixed with water? 4. Water sticking to water??? Water sticking to anything else?? 5. what is capillarity? 6. Antifreeze is used to cool off a car engine. You can replace antifreeze with water for a short time, why???? What property of water allows use to do this??? (think pasta)