Basic Chemistry

BIG IDEA: Examining substances at the molecular level helps us understand basic processes of life UNIT 2: Basic ChemistryBasic ChemistryLiving and non living things are all made of the same basic building blocks of matterBasic life processes all follow the laws of chemistry Structure of AtomsChemical ReactionsCompounds and MixturesWater-Acids and BasesStructure of AtomsStart big and end small

OrganismsOrgan Systems Organs Tissues Cells Compounds Elements AtomsSmallest amount of an element that still has the properties of that element.Atoms have structure and are made up of smaller particles that give them their characteristics and control their interactions with other atomsATOM:Structure of an AtomPPNNeeNucleus: Center of atom, where protons and neutrons are locatedStructure of an AtomPPNNeeOrbit: Area outside nucleus where electrons are in constant motionOrbits spin and rotate in three dimensions. PPNNeeStructure of an AtomEach Orbit is a specified distance from the nucleus. PPNNeeStructure of an Atom

Structure of an AtomPPNNeeNucleusOrbiteeeeeeeeeStructure of an Atom

An element has its own number of e, P and N PPNNeeStructure of an Atom---++The different combination of P, N and e make each element uniquePPNNeeStructure of an Atom---++Main Elements in Human BodyOxygenCarbonHydrogenNitrogenMain Elements in Earths crustOxygen Silicon Aluminum Iron - Protons, P+, Charge of +1 - Neutrons, N, zero charge - Electrons, e-, charge of -1Atomic particles:

Structure of an AtomNormally, all the + of the protons and the - from the electrons balance out and the overall charge of an atom is zero.Structure of an AtomWhat if an atom loses an electron? PPNNeStructure of an AtomPPNNee--++-

- Atom becomes positivePPNNeeStructure of an Atom---++What if an atom gains an electron?

- Atom becomes negativee-Any charged atom is called an ionStructure of an Atom - Positive ions are called cations - Negative ions are called anionsStructure of an Atom-The Periodic Chart

Atomic number is the number of protonsAtomic Mass is the approximate number of protons + neutronsAssume Electrons = Protons (except Ions)

21Atomic Mass = Protons + NeutronsWhy dont the electrons figure in?

22Drawing Atoms:Each orbit can hold a maximum number of electrons. - Orbit 1: holds a max of 2 - Orbit 2: holds a max of 8 - Orbit 3: holds a max of 8You must fill the inner orbits before adding electrons to the outer orbits. Electrons in the outermost orbit are called valence electrons 23Examples12Mg24PPPPPPPPPPPPNNNNNNNNNNNNeeeeeeeeeeeeExamples8O16Examples10Ne20ExamplesLook at the column on periodic table to figure out Valence electrons

C __________ N____________

ExamplesLook at the column on periodic table to figure out Valence electrons

O __________ H ____________

Chemical Reactions- BondsCompoundsAtoms are chemically bound together Definite proportions requiredProperties of a compound are different from the properties of the elements that make up that compoundMade up of many particles of the same type held together by a bond using the valence electrons

Types of bonds that form CompoundsCovalent- each atom shares electrons with the otherMolecules are formed by this type of bond

Types of bonds that form CompoundsIonic Bond- One atom gives an electron to the other

IONIC: Creates opposite charge that holds atoms togetherForm crystals

Chemical FormulasAl2O3

2Al2O3

Subscript shows how many atoms of the elementit is written afterThis number shows how many of the entire molecule their areChemical ReactionsChange in the arrangement of atoms that creates a different substanceNumber of atoms before and after the reaction are equal.A + B C synthesis reactionA B + C decompositionA + B C + D DisplacementChemical ReactionsReactants: The stuff you start withProducts: The stuff you end up withA + B CReactantsProductsChemical ReactionsC6H12 O6 + C6H12 O6 C12H22O11 + 6H2O C6H12 O6 + 6O2 6CO2 + 6H2O H20 H+ + OH-MixturesMixtures have ingredients that do not bind chemically with each otherEach ingredient keeps its own propertiesDefinite proportions not requiredTypes: solution, suspension, colloid

MixturesSolution: homogeneous; even throughout; solute (substance) completely dissolves in solvent (liquid) examples: air,

Suspension: Heterogeneous; looks even if shaken; but particles settle to bottom examples-water column in oceans and lakes

MixturesColloid: heterogeneous BUT does not settle; sort of in between the other two. Examples-milk and fog Mixtures vs. CompoundsLook at your notes: What are three big differences between Mixtures and Compounds?Properties of WaterWater is held together with special covalent bond called polar covalent bond - Means water has poles, or ends. - O is the negative end - Hs are the positive endWater is the Universal SolventImportant solvent in many solutionsAnything with a charge will attract water molecules and dissolveIonic and polar molecules have chargeNonpolar molecules (like fat) do not have charge and will not dissolveProperties of Water

Properties of WaterCohesion: Water molecules stick together because of charges

CohesionCreates Surface tension - allows stickbugs to walk on water!

AdhesionWater molecules stick to other charged substances like glass

Glass stirring rodConcept of pHpH = power of HydrogenA way of measuring how many Hydrogen ions, H+, there are in a solutionDetermines whether a solution is an acid or a baseAcids and BasesAcids: a chemical that when dissolved in water releases a hydrogen ion (H+)HX (in water) H+ + X- Properties of AcidsTaste sour think of lemonTurn litmus paper from blue to redCorrodes MetalExamples: Sulfuric Acid, Lemon Juice, Battery Acid

Acids and BasesBase: a chemical that when dissolved in water releases a hydroxide ion (OH-)XOH (in water) OH- + X+ Properties of BasesTaste bitter cough meds. Turn litmus paper back to blue after acid turns it redCan cause serious burnsExamples: Bleach, KOH, NaOH

Acids and Bases - ExamplesNaOH + H2O Na+ + OH- + H2O

HCl + H2O H+ + Cl- + H2O

Acids and Bases will cancel each other outWhen an Acid and a Base are mixed together they will Neutralize each other and create Water and a SaltThis is a Neutralization ReactionNeutralization ReactionHCl + NaOH NaCl + H2O A Salt Water

HNO3 + KOH KNO3 +H2O A salt WaterNeutral

(water)AcidBase14131211109876543210High H+Low OH-H+ = OH-High OH-Low H+pH Scale a measure of the concentration of Hydrogen IonsConcept of pHWhere is the safe pH?pH must stay between 6.5 - 7.5 in the human bodyAnother factor that must maintain homeostasis

Concept of pHAre there exceptions?Stomach is acidicIntestines are basicBuffers are necessaryweak acids or bases that react with strong acids or bases to prevent sudden changes in pH

What is the pH of Rain water??Usually between 5.6- 5.8 - Water reacts with CO2 in air to form Carbonic Acid (H2CO3)

What is the pH of Rain water??Acid Rain: - Rain water reacts with pollutants such as Sulphur dioxide and Nitrogen oxides in air - Forms Sulphuric Acid, Nitric Acid, Ammonium Sulphate - Decreases pH even further