Chemistry

1Why Take Chemistry?Guidance Ice skatingWater bugsFossil fuelsAcid rainWhy doesnt a gas tank explode?3. How does the world work?Sweat ComputersAtomic bombsFireworks2. Career2ChemistryWhat is it?Remsens study of nitric acid

Jot down your observations2Students write their own definitions.Run Remsen experiment; ask students to observe3

Ira Remsens ExperimentPenny + nitric acid observations: 3Write student observations.Show how equation corresponds to observation.s4Scientific Method OBS.HYP.EXP.THEO.a logical way to study problemsOBS.Observation(not inference)the solution turned blue4Scientific method not always followed. E.g. Einstein gedanken. Scientists use whatever works!5OBS.HYP.EXP.THEO.Hypothesis: a proposed explanation for the observation that can be tested. The copper in the penny changed to produce the blue color.6OBS.HYP.EXP.THEO.Experiment: a means to test the hypothesis. Try the same reaction using silver metal instead of a copper penny.7OBS.HYP.EXP.THEO.HYPOTHESISEXPERIMENT8OBS.HYP.EXP.THEO.Theory: an explanation of why experiments give certain results.broad in scopepredictivecan never be proven9Theory ModelModel of the atom

What is a model?

Remens experiment:Cu + 4H+ +2NO3- Cu2+ + 2NO2 + 2H2O

10Not a Bunch of Facts

Patterns !10What do you see?11ChemistryStudent definitions.Chemistry: study of thecomposition of substances &changes substances undergo.

1112Chemistry in the Real WorldTextilesFuelsMetallurgyCookingComputersPlasticsEnginesLife processesMedicineImagingPaperCeramics

Everything is a chemical !!!1213Chemistry: Brief HistoryB.C.: Some Greeks thought:Matter made of particles (atoms) vs. continuousBased on pure logic, rather than experimental

1314Middle Ages: Alchemists

15Modern Concepts1700s Antoine Lavoisier: father of modern chemistry laboratory excerpt1800s Daltonatomic theory based on data 1850s MendeleevPeriodic Table16MatterAnything that takes up space and has mass.aluminumlightwatertemperatureairheat

MATTER?16Show flask filled with water vs. air (is the air one empty?).17MatterThe amount of matter is measured by MASS not volume or weight.(water vs. air)

18Classification of Matter

19Types of Matter1.Substance (pure substance) Matter with uniform anddefinite composition.

Every sample has exactly the same properties.example: water1920Two Types of Pure SubstancesElement- simplest form of matter that can exist in the lab.e.g. C, H, etc (Periodic Table)

Compound- contains 2 or more different elements bonded together; it can be broken into simpler substances chemically.e.g. water, salt (NaCl), sugar20Start heating sugar in beaker to show decomposition.21

Sugar: C6H12O6 compoundCarbon: C elementWater: H2O compound+heatelectrical energyHydrogen: H2 element+Oxygen: O2 element21Complete the decomposition of sugar experiment and do the water hydrolysis experiment. State that the explosion of the Hindenberg was the reverse reaction.22Element vs. Compound?Classify:Water: H2O Vinegar: HC2H3O2Oxygen: O2Ozone: O323Types of Matter2. Mixturestwo or more different substances mixed togetherproportions can be varied(e.g. 20% salt in water vs. 30% salt in water)each substance retains its original properties

241. Homogeneous mixture mixture with uniform composition throughoutmixed at the molecular leveloften transparent, not cloudy synonym is solution.Mixtures: Two Typese.g. salt water, steel252. Heterogeneous mixture mixture that does not have uniform compositionoften see small chunks or pieces of different substancesoften cloudyMixtures: Two Typese.g. soil Italian salad dressing26Substance, Homogeneous or Heterogeneous Mixture ?gasolinesugarbeef stewmaple syrupgold ringwood7-UP sodasaltaircement2627Mixturescan be separated by physical meanschromatography (demo)distillation (next slide)magnetism (lab)filtration (lab)density

28

Distillation29Classification of Matter

Kool-aid cement water oxygenphysicallyseparablechemicallyseparable30States of Matter How many?SolidLiquidGasShapeDefiniteIndefiniteIndefiniteVolumeDefiniteDefiniteIndefinite Ice Water Steam4 states of matter!

30Show beaker of ice, water & water vapor.31Changing States of Matter

Raise Temperature(Temp. is a measure of the average kinetic energy of the molecules that make up the substance.)31To go from S to L to G, raise the KE by adding heat. Temperature is the measure of average KE.Only one substance on earth exists naturally as S, L & G water.32Physical PropertyQuality that can be observed without changing the substances composition.

ColorSolubilityHardnessDensityMelting pointOdorConductivityMalleability33Physical ChangeA change that does not alter the substances composition.CuttingBendingChange stateCrushing

e.g. boiling water, cutting paper34Chemical PropertyAbility of a substance to undergo a chemical reaction and form a new substance. Reactants productse.g. iron + sulfur iron(II) sulfide(NOT simply mixing iron + sulfur)

Demo35

Chemical or Physical ?? dry ice evaporatesa car fender rusts pepper is ground-up in a pepper mill bread goes stale water freezes you file your nails you take an antacid tablet36Conservation of Mass & Energy In any process or reaction, both mass and energy are conserved.e.g. burn coal:where does the mass go?where does the heat energy come from?

37Study Guide

Elements38Write the name or symbol:

fluorinezincneonchromiummanganese

IUNiAgFeWarm-up39Define chemistry

Warm-up40When water boils, it gives off air bubbles. Is this statement an observation?

Warm-up41Explain the difference between a homogeneous mixture and heterogeneous mixture.Mud?Kool Aid?Milk?

Warm-up42Super-fun element quiz!

ArgonStrontiumScandiumMercury

PbINeMgWarm-up43How many states of matter are there? Which state has a constant volume and takes the shape of its container?

Warm-up44Which state of matter has definite volume and takes the shape of its container?Define temperature.