chem10171 day1

CHEM 10171-04Dr. Nicole [email protected] Jordan Hall of Science1-1302

CHEM 13171Who should take it?Anyone whoFeels anxious about heavy first-year load as science or EG majorFeels anxious about college chemistryWants to develop good college-level study skills

Who should wait till organic?Anyone whoHad a 5 on AP Chemistry test

Why study chemistry?

Pose an explanationTry SomethingObservationAsk QuestionsPose an Explanation

ObservationAsk questionsPose an explanationTry somethingIf new observationAsk more questionsPose additional explanations

Observation(Ask questions)HypothesisExperimentObservationAsk more questionsPropose a theoryRevisehypothesisas neededFurther experimentsRevise theoryas neededMODERN SCIENTIFIC METHOD

What is chemistry?The study of matter and its properties, the changes that matter undergoes, and the energy associated with those changes. (MSS, p. 4)The study of matter and its properties, the changes that matter undergoes, and the energy associated with those changes. (MSS, p. 4)Matter anything that has mass & volume

Properties & ChangesIf you combine A&Band get C, is this achemical change orphysical change?Chemical changebecause the Substanceshave changedcomposition.

Properties & ChangesIf you combine A&Band get D, is this achemical change orphysical change?Chemical changebecause the Substanceshave changedcomposition.

Properties & ChangesIf you change theconditions C andget D, is this achemical change orphysical change?Physical changebecause the Substanceshave changedcomposition.

Properties & ChangesIf you change theconditions C andget D, does D havedifferent propertiesthan C?Same chemicalproperties b/c itsthe same substance.Different physicalproperties b/c its ina different form.

Properties & ChangesAre there chemical or physical changesbetween A and B?CC: 3Y2 + 3R -> RY2 (new composition)CC: 3R + 3B -> 3RB (new composition)PC: 3B(s) -> 3B(g)

Properties & ChangesAluminum foil is cut in halfClay is molded into a potMilk goes sourWater in an ice cube tray freezesFood scraps are compostedRubbing alcohol evaporates in your handHydrogen peroxide bubbles in a cutPPCPCPC

Properties & ChangesCan we make some generalizations about chemical and physical properties and changes?

Energy(b)Two states of the samesystem are shown as (a)and (b).

Where does eachstate belong in the PEdiagram?

Where does the PE gowhen it is lost from the state with higher PE?

Energy

MeasuringWhat is the length of the metal strip?(a) 7.5 cm(b) 7.25 cm(c) 7.4 cm(d) 7.45 cmIn science, we use significant figures all the digits you canread plus the first digit that you can estimate.

DensityDW = 1.0 g/mL, DC = 0.88 g/mL, DA = 1.4 g/mLWhich is a possible density for B? (a) 0.79 g/mL (b) 0.86 g/mL (c) 0.94 g/mL (d)1.2 g/mL

DW = 1.0 g/mL, DC = 0.88 g/mL, DA = 1.4 g/mLWhich is a possible density for B? (a) 0.79 g/mL (b) 0.86 g/mL (c) 0.94 g/mL (d)1.2 g/mLDensity = M/V units: g/mL

You have 3 pieces of metal each having the same mass.You drop each into one of three graduated cylinders eachof which started with 25.0 mL of water.Which metal is the most dense?V = 3.2 mL V = 2.9 mL V = 3.5 mL

D = M/V division by the smallest V will give the biggest D

If the mass of B is 25.0 g, what is the density of B?(a) 8.6 g/mL(b) 8.62 g/mL (c) 8.621 g/mL (d) 8.6207 g/mL

A 25.0 g sample ofwater was measuredfour times by fourdifferent students.Which student(s) was(were)precise in his/hermeasurements?Which was (were) accurate?ABDC

The volume of abox is length xwidth x height:V=LWHWhat is the volume of this box?1000010000011m100cm100cm

The volume of abox is length xwidth x height:V=LWHWhat is the volume of this box?10000100000 cm31 m3

1m100cm100cm-Apples/oranges-Canceling units-Converting unitsp. 18-21

Re-capModern scientific methodDefinition of chemistryUnderstanding of some basic concepts: physical chemical properties/changes, energy, density, measurements significant figures, accuracy/precision, units

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