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CH110CH110Foundations ofFoundations of

GENERAL, ORGANIC,GENERAL, ORGANIC,

& BIOCHEMISTRY& BIOCHEMISTRYCHEMEKETA COMMUNITY COLLEGE

INSTRUCTOR: Larry Emme

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11stst Day Stuff Day Stuff

Who are you? Are you in the right place?

GOB

CTV Introduction

Privacy waver

Course Syllabus & requirements

Who am I?

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ProloguePrologue

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Scientific Method:

Thinking like a Scientist

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Scientific MethodScientific Method

The scientific method is the process used

by scientists to explain observations in nature.

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Scientific MethodScientific Method

The scientific method involves

Making Observations

Writing a Hypothesis

Doing Experiments

Proposing a Theory

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Features of the Scientific MethodFeatures of the Scientific Method

ObservationsFacts obtained by observing and measuring events in nature.HypothesisA statement that explains the observations.ExperimentsProcedures that test the hypothesis.Theory A model that describes how the observations occur using

experimental results.

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Summary of the Scientific MethodSummary of the Scientific Method

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Major divisions of ChemistryMajor divisions of Chemistry

General General

InorganicInorganic

AnalyticalAnalytical

PhysicalPhysical

OrganicOrganic

BiochemistryBiochemistry

Elements besides CarbonElements besides Carbon

Methods of analysisMethods of analysis

Theory and conceptsTheory and concepts

Carbon based compoundsCarbon based compounds

Chemistry of living thingsChemistry of living things

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Chapter 1:Chapter 1:MeasurementMeasurement

Units of MeasurementUnits of Measurement

Significant FiguresSignificant Figures

Conversion CalculationsConversion Calculations

DensityDensity

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See Handout Sheet of See Handout Sheet of

Units of MeasurementsUnits of Measurements

Measurements in chemistry Measurements in chemistry

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MetricMetric

SISI

CommonCommon

ConversionsConversionsLengthLength

VolumeVolume

MassMass

Units of MeasurementUnits of Measurement

meter (m) 1 m = 1.09 ydmeter (m) 1 m = 1.09 yd

liter (L) 1 L = 1.06 qtliter (L) 1 L = 1.06 qt

gram (g) 1 kg = 2.2 lbgram (g) 1 kg = 2.2 lb

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Matter has MassMass and takes up space.

Matter Matter =The stuffstuff things are made of.

(Air, water, rocks, etc..)

=The amountamount of stuff (in g’s) (Bowling Ball > Balloon)

WeightWeight on earth.

=Pull of Gravity on matter.

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Mass Vs. WeightMass Vs. Weight

How much would you weigh How much would you weigh on another planet?on another planet?

http://www.exploratorium.edu/ronh/weight/

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Scientific notationScientific notation

If a number is If a number is largerlarger than 1 than 1

•Move decimal point XX places leftleft to get a number between 1 and 10.

1 2 3 , 0 0 0 , 0 0 0.

•The resulting number is multiplied by 10XX.

= 1.23 x 108

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Scientific notationScientific notation

If a number is If a number is smallersmaller than 1 than 1•Move decimal point XX places rightright to get

a number between 1 and 10.

0. 0 0 0 0 0 0 1 2 3 = 1.23 x 10-7-7

•The resulting number is multiplied by 10-X-X.

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ExamplesExamplesWrite in Scientific Notation:

25 =

8931.5 =

0.000593 =

0.0000004 =

3,210. =

2.5 2.5 10 10 11

8.9315 8.9315 10 10 33

5.93 5.93 10 10 - 4- 4

4 4 10 10 - 7- 7

3.210 3.210 10 1033

Do not press this on your calculator!

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×10

1.44939 × 10-2 =

ScientificScientific notation notation

0.0144939

On Calculator

1.44939 (-) 2EE

Means ×10 Change

Sign

1.44939E -2

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Measured & Exact NumbersMeasured & Exact Numbers

Exact Numbers =Exact Numbers = from counting or by definition

12 coins per package12 coins per package

12 coins 1 package

12 coins 1 package

1 package12 coins

1 package12 coins=

12 coins 1 dozen coins 12 coins

1 dozen coins 1 dozen coins

12 coins 1 dozen coins

12 coins=

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Measured & Exact NumbersMeasured & Exact Numbers

Measured Numbers =Measured Numbers = estimated using a tool

• We make errors We make errors

• Tools have limitsTools have limits

All measurements contain some uncertaintyuncertainty.

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AccuracyAccuracy

How close are we to the true value?

TruthTruth

PrecisionPrecision

How well do our values agree?

ConsistencyConsistency

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Length of object is between 6.7 and 6.8The next digit would be a guess.            

Significant figuresSignificant figures

If use 6.76 then have error of + 0.01cm

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Significant figuresSignificant figures

Expresses accuracy & precision.accuracy & precision.

You can’t report numbers better than the method used to measure them.

6.76.766 units = 33 sig figures

Certain Digits

UncertainDigit

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Significant figuresSignificant figures

Sig Figs don’t depend on the decimal point.Sig Figs don’t depend on the decimal point.

255 millimetersmillimeters

25.5 centimeterscentimeters

2.55 decimetersdecimeters

0.255 metersmeters

0.0255 decametersdecameters

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Significant figures: Rules for zerosSignificant figures: Rules for zeros

0.00421 Leading zeroLeading zero

Captive zeros areare significant. 4012

Trailing zeros behind decimal areare significant.114.20

Captive zeroCaptive zero

Trailing zeroTrailing zero

Leading zeros are notare not significant.

33 sig figs

44 sig figs

55 sig figs

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32,00032,000Are the 0’s significant?

22 sig figs =

33 sig figs =

44 sig figs =

55 sig figs =

Significant figures: Rules for zerosSignificant figures: Rules for zeros

__

32,000 or 3.2 x 1032,000 or 3.2 x 1044

32000 or 3.20 x 1032000 or 3.20 x 1044

32000 or32000 or 3.200 x 103.200 x 1044

32000 or32000 or 3.2000 x 103.2000 x 1044

32000.32000.

__

__

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1025 km

2.00 mg

0.00570

520

Significant figures: Rules for zerosSignificant figures: Rules for zeros

ThreeThree (only trailing zero behind decimal

is significant, leading zeros are not)

FourFour (Captive zeros are significant)

ThreeThree (trailing zeros behind decimal

are significant)

TwoTwo (No decimal, zero assumed insignif)

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Write with 4 Significant Figures:

2.5792.57955035035

RoundingRounding

1st insignificant digit1st insignificant digit

34.2034.2044221221 becomes 34.2034.20

becomes 2.5802.580

>> 5 5 round up

< 5 < 5 round down.

>> 5 5 round up

< 5 < 5 round down.

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Significant figuresSignificant figuresand calculationsand calculations

An answer can’t have greater significance than the quantities used to produce it.

speed = 1.0 km 3.00 min

+

-1

/

x

0

2 3

4 5 6

7 8 9

.

CE

EE

log

ln

1/x

x2

cos tan

0.3333333333

= ??

ExampleExample How fast did you run if youwent 1.0 km in 3.00 minutes?

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Simplified rules for significant figuresSimplified rules for significant figuresMultiplication & Division Problems:Multiplication & Division Problems:

• Do calculations.

•Look at sig figs for each value in calculation. (Constants don’t count.)

•Report answer with same sig figs as leastleast significant value.

•Round off as needed.

speed = 1.0 km 3.00 min

= 0.333333333 0.333333333 kmkm minmin

= 0.33 0.33 kmkm minmin

2 sig figs3 sig figs

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Simplified rules for significant figuresSimplified rules for significant figuresAddition & Subtraction Problems:Addition & Subtraction Problems:

• Do calculations.

•Look at least significant placeplace for each value in calculation.

•Report answer to least significant place.

•Round off as needed.

1.9+ 18.65 20.55

= 20.6 = 20.6

Significant to .1

Significant to .01

Significant to .1

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Metric prefixesMetric prefixesChanging the prefix alters the size of a unit.

Prefix SymbolPrefix Symbol Factor (multiple) Factor (multiple)

mega M 106 1,000,000

kilo k 103 1,000

deci d 10-1 0.1

centi c 10-2 0.01

milli m 10-3 0.001

101000 1 1

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Problem Solving Using Conversion Factors

Many problems require a change of one unit to another unit by using conversion factors (fractions).

unit1 × conversion factor = unit2

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How many feet are there in 22.5 inches?

It must cancel inches.

It must introduce feet

unit1 × conversion factor = unit2

inches × conversion factor = feet

The conversion factor must accomplish two things:

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The conversion factor takes a fractional form.

ftin = ft

in

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Putting in the measured value and the ratio of feet to inches produces:

1 ft22.5 in = 1.875 ft

12 in

= 1.88 ft

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Convert 3.7×1015 inches to miles.

153.7 10 in 1 ftx

12 in

1 milex

5280 ft10 = 5.8 10 miles

Inches can be converted to miles by writing down conversion factors in succession.

in ft miles

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Convert 4.51030 cm to kilometers.

304.5 10 cm 1 mx

100 cm

1 kmx

1000 m25 = 4.5 10 km

Centimeters can be converted to kilometers by writing down conversion factors in succession.

cm m km

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Conversion of unitsConversion of units

Examples:Examples:

10.7 T = ? fl oz

62.04 mi = ? in

5 kg = ? mg

9.3 ft = ? cm

5.7 g/ml = ? lbs/qt

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DensityDensity

Water 1.0Water 1.0 UrineUrine 1.01 - 1.031.01 - 1.03

AirAir 0.0013 0.0013 BoneBone 1.7 - 2.01.7 - 2.0

GoldGold 19.3 19.3 OilOil 0.8 - 0.90.8 - 0.9

Density =Density = MassMass

VolumeVolume

1cccc = 1 cmcm33 = 1 mlml = 1 gg water 1cccc = 1 cmcm33 = 1 mlml = 1 gg water

g g

cmcm33

g g

mlmlor AtAt 4 4 oo C C

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Density calculationDensity calculation

What is the density of 5.00 ml5.00 ml of serum if it has a mass of 5.230 g5.230 g?

= 1.05 = 1.05 g g mlml

d =d = mm VV

d =d = 5.230 g5.230 g 5.00 ml5.00 ml

VV = = mm dd

m m = = V V dd

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Specific gravitySpecific gravity

Specific Gravity =Specific Gravity = density of substance g

mldensity of reference g

ml

ReferenceReference

commonly commonly water at water at

44ooCC•Specific Gravity is unitlessunitless..

•At 44ooCC, density = specific gravity.density = specific gravity.

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Specific gravitySpecific gravity

•Commonly used to test sugar in urine.

Hydrometer

•Float height will be based on Specific

Gravity.

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Density as a ConversionDensity as a ConversionA liquid sample with a density of 1.09 g/mL is

found to weigh 7.453 grams. What is the volume of the liquid in mLs?

A liquid sample with a density of 1.09 g/mL is found to weigh 7.453 grams. What is the volume of the liquid in mLs?

1.09 g1.09 g1 ml1 ml

1 ml1 ml1.09 g1.09 g

• Identify any conversion factors.

•How should the answer look?

7.453 g7.453 g = ml= ml

• What is unique to the problem?

1.0 ml1.0 ml1.09 g1.09 g

6.8376146.837614 = = 6.846.84 ml ml