Introduction to Chemistry and Measurement

Welcome to theWorld ofChemistryWelcome to theWorld ofChemistry

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The Language of ChemistryThe Language of Chemistry

•CHEMICAL _____________ -•CHEMICAL _____________ -

–pure substances that cannot be decomposed byordinary means to other substances.–pure substances that cannot be decomposed byordinary means to other substances.

Sodium

Bromine

Aluminum

The Language of ChemistryThe Language of Chemistry

•The elements,their names, andsymbols are givenon thePERIODICTABLE•The elements,their names, andsymbols are givenon thePERIODICTABLE

•How manyelements arethere?•How manyelements arethere?

117 elements have been identified117 elements have been identified

• 82 elements occur naturally on Earth• 82 elements occur naturally on Earth

Examples: gold, aluminum, lead, oxygen, carbonExamples: gold, aluminum, lead, oxygen, carbon

•35 elements have been created by scientists•35 elements have been created by scientists

Examples: technetium, americium, seaborgiumExamples: technetium, americium, seaborgium

The Periodic TableThe Periodic Table

Dmitri Mendeleev (1834 - 1907)Dmitri Mendeleev (1834 - 1907)

Glenn Seaborg(1912-1999)Glenn Seaborg(1912-1999)

•Discovered 8new elements.•Discovered 8new elements.

•Only livingperson forwhom anelement wasnamed.•Only livingperson forwhom anelement wasnamed.

Branches of Chemistry

•Many major areas of study forspecialization•Many major areas of study forspecialization

•Several career opportunities•Several career opportunities

•Also used in many other jobs•Also used in many other jobs

1. Organic Chemistry

•Organic is the study ofmatter that contains carbon•Organic is the study ofmatter that contains carbon

•Organic chemists study thestructure, function,synthesis, and identity ofcarbon compounds•Organic chemists study thestructure, function,synthesis, and identity ofcarbon compounds

•Useful in petroleumindustry, pharmaceuticals,polymers•Useful in petroleumindustry, pharmaceuticals,polymers

2. Inorganic Chemistry

•Inorganic is thestudy of matter thatdoes NOT containcarbon•Inorganic is thestudy of matter thatdoes NOT containcarbon

•Inorganic chemistsstudy the structure,function, synthesis,and identity of non-carbon compounds•Inorganic chemistsstudy the structure,function, synthesis,and identity of non-carbon compounds

•Polymers,Metallurgy•Polymers,Metallurgy

3. Biochemistry

•Biochemistry isthe study ofchemistry inliving things•Biochemistry isthe study ofchemistry inliving things

•Cross betweenbiology andchemistry•Cross betweenbiology andchemistry

•Pharmaceuticalsand genetics•Pharmaceuticalsand genetics

4. Physical Chemistry

•Physicalchemistry is thephysics ofchemistry… theforces of matter•Physicalchemistry is thephysics ofchemistry… theforces of matter

•Much of p-chemis computational•Much of p-chemis computational

•Developtheoretical ideasfor newcompounds•Developtheoretical ideasfor newcompounds

HONK if you passed p-chem

5. Analytical Chemistry

•Analyticalchemistry is thestudy of highprecisionmeasurement•Analyticalchemistry is thestudy of highprecisionmeasurement

•Find compositionand identity ofchemicals•Find compositionand identity ofchemicals

•Forensics, qualitycontrol, medicaltests•Forensics, qualitycontrol, medicaltests

Types of Observations andMeasurementsTypes of Observations andMeasurements

•We make QUALITATIVEobservations of reactions —changes in color and physicalstate.•We make QUALITATIVEobservations of reactions —changes in color and physicalstate.

•We also make QUANTITATIVEMEASUREMENTS, which involvenumbers.•We also make QUANTITATIVEMEASUREMENTS, which involvenumbers.

–Use SI units — based on themetric system–Use SI units — based on themetric system

SI measurementSI measurement

•Le Système internationald'unités•Le Système internationald'unités

•The only countries that have notofficially adopted SI are Liberia(in western Africa) and Myanmar(a.k.a. Burma, in SE Asia), butnow these are reportedly usingmetric regularly•The only countries that have notofficially adopted SI are Liberia(in western Africa) and Myanmar(a.k.a. Burma, in SE Asia), butnow these are reportedly usingmetric regularly

•Metrication is a process thatdoes not happen all at once, butis rather a process that happensover time.•Metrication is a process thatdoes not happen all at once, butis rather a process that happensover time.

•Among countries with non-metric usage, the U.S. is the onlycountry significantly holdingout.The U.S. officially adoptedSI in 1866.•Among countries with non-metric usage, the U.S. is the onlycountry significantly holdingout. The U.S. officially adoptedSI in 1866.

Information from U.S. MetricAssociation

Chemistry In ActionChemistry In Action

On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mars’atmosphere 100 km lower than planned and was destroyed byheat.

1 lb = 1 N

1 lb = 4.45 N

“This is going to be thecautionary tale that will beembedded into introductionto the metric system inelementary school, highschool, and college sciencecourses till the end of time.”

Standards of MeasurementStandards of Measurement

When we measure, we use a measuring tool tocompare some dimension of an object to a standard.When we measure, we use a measuring tool tocompare some dimension of an object to a standard.

For example, at one time thestandard for length was theking’s foot. What are someproblems with this standard?For example, at one time thestandard for length was theking’s foot. What are someproblems with this standard?

What is Scientific Notation?What is Scientific Notation?

•Scientific notation is a way ofexpressing really big numbers orreally small numbers.•Scientific notation is a way ofexpressing really big numbers orreally small numbers.

•For very large and very smallnumbers, scientific notation ismore concise.•For very large and very smallnumbers, scientific notation ismore concise.

Scientific notation consists oftwo parts:Scientific notation consists oftwo parts:

•A number between 1 and 10•A number between 1 and 10

•A power of 10•A power of 10

N x 10xN x 10x

To change standard form toscientific notation…To change standard form toscientific notation…

•Place the decimal point so that there isone non-zero digit to the left of thedecimal point.•Place the decimal point so that there isone non-zero digit to the left of thedecimal point.

•Count the number of decimal placesthe decimal point has “moved” fromthe original number. This will be theexponent on the 10.•Count the number of decimal placesthe decimal point has “moved” fromthe original number. This will be theexponent on the 10.

•If the original number was less than 1,then the exponent is negative. If theoriginal number was greater than 1,then the exponent is positive.•If the original number was less than 1,then the exponent is negative. If theoriginal number was greater than 1,then the exponent is positive.

ExamplesExamples

•Given: 289,800,000•Given: 289,800,000

•Use: 2.898 (moved 8 places)•Use: 2.898 (moved 8 places)

•Answer: 2.898 x 108•Answer: 2.898 x 108

•Given: 0.000567•Given: 0.000567

•Use: 5.67 (moved 4 places)•Use: 5.67 (moved 4 places)

•Answer: 5.67 x 10-4•Answer: 5.67 x 10-4

To change scientific notationto standard form…To change scientific notationto standard form…

•Simply move the decimal point tothe right for positive exponent 10.•Simply move the decimal point tothe right for positive exponent 10.

•Move the decimal point to the leftfor negative exponent 10.•Move the decimal point to the leftfor negative exponent 10.

(Use zeros to fill in places.)(Use zeros to fill in places.)

ExampleExample

•Given: 5.093 x 106•Given: 5.093 x 106

•Answer: 5,093,000 (moved 6 placesto the right)•Answer: 5,093,000 (moved 6 placesto the right)

•Given: 1.976 x 10-4•Given: 1.976 x 10-4

•Answer: 0.0001976 (moved 4 placesto the left)•Answer: 0.0001976 (moved 4 placesto the left)

Learning Check

•Express these numbers inScientific Notation:•Express these numbers inScientific Notation:

1) 4057891) 405789

2) 0.0038722) 0.003872

3) 30000000003) 3000000000

4) 24) 2

5) 0.4782605) 0.478260

Stating a MeasurementStating a Measurement

In every measurement there is aIn every measurement there is a

Number followed by aNumber followed by a

 Unit from a measuring device Unit from a measuring device

The number should also be as precise as the measurement!The number should also be as precise as the measurement!

UNITS OF MEASUREMENTUNITS OF MEASUREMENT

Use SI units — based on the metricsystemUse SI units — based on the metricsystem

LengthLength

MassMass

VolumeVolume

TimeTime

TemperatureTemperature

Meter, mMeter, m

Kilogram, kgKilogram, kg

Seconds, sSeconds, s

Celsius degrees, ˚CCelsius degrees, ˚C

kelvins, Kkelvins, K

Liter, LLiter, L

Mass vs. WeightMass vs. Weight

•Mass: Amountof Matter (grams,measured with aBALANCE)•Mass: Amountof Matter (grams,measured with aBALANCE)

•Weight: Forceexerted by themass, onlypresent withgravity (pounds,measured with aSCALE)•Weight: Forceexerted by themass, onlypresent withgravity (pounds,measured with aSCALE)

Can you hearme now?Can you hearme now?

Some Tools for MeasurementSome Tools for Measurement

Which tool(s)would you use tomeasure:Which tool(s)would you use tomeasure:

A. temperatureA. temperature

B. volumeB. volume

C. timeC. time

D. weightD. weight

Learning Check

Match L) length M) mass V) volumeMatch L) length M) mass V) volume

____ A. A bag of tomatoes is 4.6 kg.____ A. A bag of tomatoes is 4.6 kg.

____ B. A person is 2.0 m tall.____ B. A person is 2.0 m tall.

____ C. A medication contains 0.50 g Aspirin.____ C. A medication contains 0.50 g Aspirin.

____ D. A bottle contains 1.5 L of water.____ D. A bottle contains 1.5 L of water.

Learning CheckLearning Check

What are some U.S. units that are used tomeasure each of the following?What are some U.S. units that are used tomeasure each of the following?

A. lengthA. length

B. volumeB. volume

C. weightC. weight

D. temperatureD. temperature

Metric PrefixesMetric Prefixes

•Kilo- means 1000 of that unit•Kilo- means 1000 of that unit

–1 kilometer (km) = 1000 meters (m)–1 kilometer (km) = 1000 meters (m)

•Centi- means 1/100 of that unit•Centi- means 1/100 of that unit

–1 meter (m) = 100 centimeters (cm)–1 meter (m) = 100 centimeters (cm)

–1 dollar = 100 cents–1 dollar = 100 cents

•Milli- means 1/1000 of that unit•Milli- means 1/1000 of that unit

–1 Liter (L) = 1000 milliliters (mL)–1 Liter (L) = 1000 milliliters (mL)

Metric PrefixesMetric Prefixes

Metric PrefixesMetric Prefixes

1. 1000 m = 1 ___a) mm b) km c) dm1. 1000 m = 1 ___a) mm b) km c) dm

2. 0.001 g = 1 ___ a) mg b) kg c) dg2. 0.001 g = 1 ___ a) mg b) kg c) dg

3. 0.1 L = 1 ___a) mL b) cL c) dL3. 0.1 L = 1 ___a) mL b) cL c) dL

4. 0.01 m = 1 ___ a) mm b) cm c) dm4. 0.01 m = 1 ___ a) mm b) cm c) dm

Learning Check

Units of LengthUnits of Length

•? kilometer (km) = 500 meters (m)•? kilometer (km) = 500 meters (m)

•2.5 meter (m) = ? centimeters (cm)•2.5 meter (m) = ? centimeters (cm)

•1 centimeter (cm) = ? millimeter (mm)•1 centimeter (cm) = ? millimeter (mm)

•1 nanometer (nm) = 1.0 x 10-9 meter•1 nanometer (nm) = 1.0 x 10-9 meter

O—H distance =O—H distance =

9.4 x 10-11 m9.4 x 10-11 m

9.4 x 10-9 cm9.4 x 10-9 cm

0.094 nm0.094 nm

O—H distance =O—H distance =

9.4 x 10-11 m9.4 x 10-11 m

9.4 x 10-9 cm9.4 x 10-9 cm

0.094 nm0.094 nm

Learning Check

Select the unit you would use to measureSelect the unit you would use to measure

1. Your height1. Your height

a) millimeters b) meters c) kilometersa) millimeters b) meters c) kilometers

2. Your mass2. Your mass

a) milligramsb) grams c) kilogramsa) milligramsb) grams c) kilograms

3. The distance between two cities3. The distance between two cities

a) millimetersb) meters c) kilometersa) millimetersb) meters c) kilometers

4. The width of an artery4. The width of an artery

a) millimetersb) meters c) kilometersa) millimetersb) meters c) kilometers

Conversion FactorsConversion Factors

Fractions in which the numerator anddenominator are EQUAL quantities expressedin different unitsFractions in which the numerator anddenominator are EQUAL quantities expressedin different units

Example: 1 in. = 2.54 cm

Factors: 1 in. and 2.54 cm

2.54 cm 1 in.

Learning Check

Write conversion factors that relate each ofthe following pairs of units:Write conversion factors that relate each ofthe following pairs of units:

1. Liters and mL1. Liters and mL

2. Hours and minutes2. Hours and minutes

3. Meters and kilometers3. Meters and kilometers

How many minutes are in 2.5 hours?

Conversion factor

2.5 hr x 60 min = 150 min 2.5 hr x 60 min = 150 min

1 hr 1 hr

cancel

By using dimensional analysis / factor-label method,the UNITS ensure that you have the conversion rightside up, and the UNITS are calculated as well as thenumbers!By using dimensional analysis / factor-label method,the UNITS ensure that you have the conversion rightside up, and the UNITS are calculated as well as thenumbers!

Steps to Problem SolvingSteps to Problem Solving

1.Write down the given amount. Don’t forget the units!

2.Multiply by a fraction.

3.Use the fraction as a conversion factor. Determine ifthe top or the bottom should be the same unit as thegiven so that it will cancel.

4.Put a unit on the opposite side that will be the newunit. If you don’t know a conversion between thoseunits directly, use one that you do know that is a steptoward the one you want at the end.

5.Insert the numbers on the conversion so that the topand the bottom amounts are EQUAL, but in differentunits.

6.Multiply and divide the units (Cancel).

7.If the units are not the ones you want for your answer,make more conversions until you reach that point.

8.Multiply and divide the numbers. Don’t forget“Please Excuse My Dear Aunt Sally”! (order ofoperations)

Sample Problem

•You have $7.25 in your pocket inquarters. How many quarters do youhave?•You have $7.25 in your pocket inquarters. How many quarters do youhave?

7.25 dollars 4 quarters7.25 dollars 4 quarters

1 dollar 1 dollar

= 29 quarters= 29 quarters

You Try This One!You Try This One!

If Jacob stands onSpencer’s shoulders,they are two and a halfyards high. How manyfeet is that?If Jacob stands onSpencer’s shoulders,they are two and a halfyards high. How manyfeet is that?

Learning Check

A rattlesnake is 2.44 m long. Howlong is the snake in cm?A rattlesnake is 2.44 m long. Howlong is the snake in cm?

a) 2440 cma) 2440 cm

b)244 cmb)244 cm

c)24.4 cmc)24.4 cm

Solution

A rattlesnake is 2.44 m long. Howlong is the snake in cm?A rattlesnake is 2.44 m long. Howlong is the snake in cm?

b)244 cmb)244 cm

2.44 m x 100 cm = 244 cm2.44 m x 100 cm = 244 cm

1 m

Learning Check

How many seconds are in 1.4 days?

Unit plan: days hr min seconds

1.4 days x 24 hr x ??

1 day

Wait a minute!

What is wrong with the following setup?What is wrong with the following setup?

1.4 day x 1 day x 60 min x 60 sec1.4 day x 1 day x 60 min x 60 sec

24 hr 1 hr 1 min 24 hr 1 hr 1 min

English and Metric ConversionsEnglish and Metric Conversions

•If you know ONE conversion foreach type of measurement, youcan convert anything!•If you know ONE conversion foreach type of measurement, youcan convert anything!

•You must memorize and use theseconversions:•You must memorize and use theseconversions:

–Mass: 454 grams = 1 pound–Mass: 454 grams = 1 pound

–Length: 2.54 cm = 1 inch–Length: 2.54 cm = 1 inch

–Volume: 0.946 L = 1 quart–Volume: 0.946 L = 1 quart

Learning CheckLearning Check

An adult human has 4.65 L of blood. Howmany gallons of blood is that?An adult human has 4.65 L of blood. Howmany gallons of blood is that?

Unit plan: L qt gallon

Equalities:1 quart = 0.946 L

1 gallon = 4 quarts

Your Setup:

Equalities

State the same measurement in two differentunitsState the same measurement in two differentunits

lengthlength

10.0 in.10.0 in.

25.4 cm25.4 cm

Steps to Problem SolvingSteps to Problem Solving

 Read problem Read problem

 Identify data Identify data

 Make a unit plan from the initial unit to thedesired unit Make a unit plan from the initial unit to thedesired unit

 Select conversion factors Select conversion factors

 Change initial unit to desired unit Change initial unit to desired unit

 Cancel units and check Cancel units and check

 Do math on calculator Do math on calculator

 Give an answer using significant figures Give an answer using significant figures

Dealing with Two Units – Honors OnlyDealing with Two Units – Honors Only

If your pace on a treadmill is 65 metersper minute, how many seconds will ittake for you to walk a distance of 8450feet? If your pace on a treadmill is 65 metersper minute, how many seconds will ittake for you to walk a distance of 8450feet?

What about Square and Cubic units? –Honors OnlyWhat about Square and Cubic units? –Honors Only

•Use the conversion factors you alreadyknow, but when you square or cube theunit, don’t forget to cube the numberalso!•Use the conversion factors you alreadyknow, but when you square or cube theunit, don’t forget to cube the numberalso!

•Best way: Square or cube the ENITREconversion factor•Best way: Square or cube the ENITREconversion factor

•Example: Convert 4.3 cm3 to mm3•Example: Convert 4.3 cm3 to mm3

4.3 cm3 10 mm 34.3 cm3 10 mm 3

1 cm 1 cm

( )

4.3 cm3 103 mm34.3 cm3 103 mm3

13 cm3 13 cm3

= 4300 mm3

Learning CheckLearning Check

•A Nalgene waterbottle holds 1000cm3 of dihydrogenmonoxide(DHMO). Howmany cubicdecimeters isthat?•A Nalgene waterbottle holds 1000cm3 of dihydrogenmonoxide(DHMO). Howmany cubicdecimeters isthat?

SolutionSolution

1000 cm3 1 dm 31000 cm3 1 dm 3

10 cm 10 cm

( )

= 1 dm3= 1 dm3

So, a dm3 is the same as a Liter !So, a dm3 is the same as a Liter !

A cm3 is the same as a milliliter.A cm3 is the same as a milliliter.

Temperature ScalesTemperature Scales

•Fahrenheit•Fahrenheit

•Celsius•Celsius

•Kelvin•Kelvin

Anders Celsius

1701-1744

Lord Kelvin

(William Thomson)

1824-1907

Temperature ScalesTemperature Scales

1 kelvin = 1 degree CelsiusNotice that 1 kelvin = 1 degree Celsius

Boiling pointof waterBoiling pointof water

Freezing pointof waterFreezing pointof water

CelsiusCelsius

100 ˚C100 ˚C

0 ˚C0 ˚C

100˚C100˚C

KelvinKelvin

373 K373 K

273 K273 K

100 K100 K

FahrenheitFahrenheit

32 ˚F32 ˚F

212 ˚F212 ˚F

180˚F180˚F

Calculations UsingTemperatureCalculations UsingTemperature

•Generally require temp’s in kelvins•Generally require temp’s in kelvins

•T (K) = t (˚C) + 273.15•T (K) = t (˚C) + 273.15

•Body temp = 37 ˚C + 273 = 310 K•Body temp = 37 ˚C + 273 = 310 K

•Liquid nitrogen = -196 ˚C + 273 = 77 K•Liquid nitrogen = -196 ˚C + 273 = 77 K

•Generally require temp’s in kelvins•Generally require temp’s in kelvins

•T (K) = t (˚C) + 273.15•T (K) = t (˚C) + 273.15

•Body temp = 37 ˚C + 273 = 310 K•Body temp = 37 ˚C + 273 = 310 K

•Liquid nitrogen = -196 ˚C + 273 = 77 K•Liquid nitrogen = -196 ˚C + 273 = 77 K

Fahrenheit FormulaFahrenheit Formula

Zero point: 0°C = 32°FZero point: 0°C = 32°F

°F = 9/5 °C + 32°F = 9/5 °C + 32

Celsius FormulaCelsius Formula

Rearrange to find T°CRearrange to find T°C

°F = 9/5 °C + 32°F = 9/5 °C + 32

°F - 32 = 9/5 °C ( +32 - 32)°F - 32 = 9/5 °C ( +32 - 32)

°F - 32 = 9/5 °C°F - 32 = 9/5 °C

9/5 9/5 9/5 9/5

(°F - 32) * 5/9 = °C(°F - 32) * 5/9 = °C

Temperature ConversionsTemperature Conversions

A person with hypothermia has a bodytemperature of 29.1°C. What is the bodytemperature in °F?A person with hypothermia has a bodytemperature of 29.1°C. What is the bodytemperature in °F?

°F = 9/5 (29.1°C) + 32°F = 9/5 (29.1°C) + 32

= 52.4 + 32 = 52.4 + 32

= 84.4°F= 84.4°F

Learning CheckLearning Check

The normal temperature of a chickadee is105.8°F. What is that temperature in °C? The normal temperature of a chickadee is105.8°F. What is that temperature in °C?

1) 73.8 °C1) 73.8 °C

2) 58.8 °C2) 58.8 °C

3) 41.0 °C3) 41.0 °C

Learning Check

Pizza is baked at 455°F. What is that in °C?

1) 437 °C1) 437 °C

2) 235°C2) 235°C

3) 221°C3) 221°C