Introduction to Introduction to ChemistryChemistryand and Matter and EnergyMatter and Energy

Summer’s overSummer’s over

Hang tightHang tight

It’s going to be an exciting ride!It’s going to be an exciting ride!

What is Chemistry?What is Chemistry?

What is Matter?What is Matter?

What is Non-Matter?What is Non-Matter?

Why Study Chemistry?Why Study Chemistry?

• Central, fundamental science.Central, fundamental science.• Other sciences used chemistry as their Other sciences used chemistry as their

backbone.backbone.– Health care, conservation of natural Health care, conservation of natural

resources, protection of the environment, resources, protection of the environment, food production, clothing, manufacturing, food production, clothing, manufacturing, production of shelter, etc…production of shelter, etc…

Scientific laws are the evidence used to support a conclusion. 

Scientific hypotheses and theories are our best attempts at explaining the behavior of the world, in ways that can be tested by further experiment. 

Scientific law: a generalized description, usually expressed in mathematical terms, which describes the empirical behavior of matter.

Scientific laws describe things.  They do not

explain them.

We don't prove theories (and hypotheses) true.  We just use the observations to convince ourselves (and others) that we have a good idea.  Scientists have a lot of confidence in scientific theories, because they know there is a lot of evidence to back them up.

Measurement and Scientific NotationMeasurement and Scientific Notation• Measurement define qualitative properties of a substance.Measurement define qualitative properties of a substance.• Often in science, measurements require very large or very Often in science, measurements require very large or very

small numbers. small numbers. • Scientific notation = a number between 1 and 10 multiplied Scientific notation = a number between 1 and 10 multiplied

by 10 raised to a power.by 10 raised to a power.• The number of places the decimal point has moved The number of places the decimal point has moved

determines the power of 10. If the decimal point has moved determines the power of 10. If the decimal point has moved to the to the ____________then the power is then the power is ______________, to the , to the _____, _____, ______________________..

e.g. e.g. 602,000,000,000,000,000,000,000.0602,000,000,000,000,000,000,000.0

= =

e.g. 0.00524e.g. 0.00524

= =

Convert the following:Convert the following:

Convert to scientific Convert to scientific notationnotation

1.1. 2450024500

2.2. 356356

3.3. 0.0009850.000985

4.4. 0.2220.222

5.5. 1220012200

Convert to non-scientific notation numbers

1.1. 4.2 X 104.2 X 10-3-3

2.2. 2.15 X 102.15 X 1044

3.3. 3.14 X 103.14 X 10-6-6

4.4. 9.22 X 109.22 X 1055

5.5. 9.57 X 109.57 X 1022

Mathematics of ScienceMathematics of SciencePrecision, Accuracy, and Significant Precision, Accuracy, and Significant FiguresFigures• No measurement of a No measurement of a

physical quantity is physical quantity is absolutely certain.absolutely certain.

• All measurements All measurements include a certain include a certain degree of uncertaintydegree of uncertainty

Causes of uncertainty:Causes of uncertainty:

a.a.

b.b.

PrecisionPrecision= =

AccuracyAccuracy = =

Consider three sets of data that have been Consider three sets of data that have been recorded after measuring a piece of wood that recorded after measuring a piece of wood that was exactly 6.000 m long.was exactly 6.000 m long.

Set XSet X Set YSet Y Set ZSet Z

5.864 m5.864 m 6.002 m6.002 m 5.872 m5.872 m

5.878 m5.878 m 6.004 m6.004 m 5.868 m5.868 m

Average Average LengthLength

5.871 m5.871 m 6.003 m6.003 m 5.870 m5.870 m

1. Which set of data is the most accurate?

2. Which set of data is the most precise?

• Significant figuresSignificant figures- measurements include one - measurements include one uncertain figure in addition to those known with uncertain figure in addition to those known with certainty.certainty.

• Rules for Significant FiguresRules for Significant Figures1.    All digits 1-9 are significant1.    All digits 1-9 are significantI.e.- 129I.e.- 129

2.  Zeros between sig. Figs. are always significant2.  Zeros between sig. Figs. are always significantI.e.- 5007I.e.- 5007

3.  Trailing zeros in a number are significant only if the number contains a decimal pt.3.  Trailing zeros in a number are significant only if the number contains a decimal pt.I.e.- 1000.0 I.e.- 1000.0 100 100

4.  Zeros in the beginning of a number whose only function is to place the decimal point are 4.  Zeros in the beginning of a number whose only function is to place the decimal point are not significant.not significant.

I.e.- 0.0025 I.e.- 0.0025

5.  Zeros following a decimal sig fig are significant.5.  Zeros following a decimal sig fig are significant.I.e.- 0.000470I.e.- 0.000470

6.  A bar over a zero indicates significance6.  A bar over a zero indicates significanceI.e.- 6400 I.e.- 6400

11

Atlantic – Pacific RuleAtlantic – Pacific Rule• If a decimal is If a decimal is ppresent, count resent, count

from the from the Pacific Pacific side.side.• If a decimal is If a decimal is aabsent, count bsent, count

from the from the AtlanticAtlantic side. side.

Start counting from the first Start counting from the first nonzero digit you find, and nonzero digit you find, and count every digit including zero count every digit including zero thereafter!thereafter!

Significant Figures PracticeSignificant Figures Practice

• Determine the number of Determine the number of significant figures in the significant figures in the followingfollowing

1.1. 250.7250.7

2.2. 0.000770.00077

3.3. 10241024

4.4. 4.7 X 104.7 X 10-5-5

5.5. 34000003400000

6.6. 500.0500.0

7.7. 0.2309700.230970

8.8. 0.034000.03400

9.9. 0.340300.34030

10.10. 2626

• Calculate the following to Calculate the following to the correct number of sig. the correct number of sig. figs.figs.

1.1. 34.5 X 23.4634.5 X 23.46

2.2. 123/3123/3

3.3. 2.61X102.61X10-1-1 X 356 X 356

4.4. 21.78 + 45.8621.78 + 45.86

5.5. 23.88887-11.223.88887-11.2

6.6. 6-3.06-3.0

7.7. 32.559 X 34.55532.559 X 34.555

8.8. 4433-11874433-1187

9.9. 1.2 X 4.31.2 X 4.3

10.10. 8.08 + 21.988.08 + 21.98

Rules for Calculations Using Rules for Calculations Using Significant FiguresSignificant Figures

Multiplication and DivisionMultiplication and Division- limit and round to - limit and round to the least number of sig figs in any of the the least number of sig figs in any of the factors. factors.

I.e.- 144.6 X .0023 = ?I.e.- 144.6 X .0023 = ?

Addition and Subtraction RuleAddition and Subtraction Rule- limit and round - limit and round to least number of decimal places in any of to least number of decimal places in any of the numbers that make up the problem.the numbers that make up the problem.

I.e.- 5.42 g + 131.1 g = ?I.e.- 5.42 g + 131.1 g = ?

SI UnitsSI Units- preferred metric units - preferred metric units used in science.used in science.

Base QuantityBase Quantity Name of UnitName of Unit SymbolSymbol

MassMass GramGram gg

LengthLength MeterMeter mm

TimeTime SecondSecond ss

Amount of Amount of SubstanceSubstance

MoleMole molmol

TemperatureTemperature KelvinKelvin KK

Metric ConversionMetric Conversion

PrefixPrefix SymbolSymbol MeaningMeaning

MegaMega MM

KiloKilo kk

DeciDeci dd

CentiCenti cc

MilliMilli mm

MicroMicro

NanoNano nn

Unit Conversion Using Dimensional AnalysisUnit Conversion Using Dimensional Analysis

1.1. Write the term to be convertedWrite the term to be converted- both the number - both the number and the unit.and the unit.

0.0342g0.0342g2.2. Write the conversion formulasWrite the conversion formulas

1 g = 1000 mg1 g = 1000 mg3.3. Make a fraction of the conversion formula such Make a fraction of the conversion formula such

thatthat a. if the unit in step 1 is in the numerator, the a. if the unit in step 1 is in the numerator, the same unit in step 3 must be in the denominatorsame unit in step 3 must be in the denominatorb. if the unit in step 1 is in the denominator, the b. if the unit in step 1 is in the denominator, the same unit in step 3 must be in the numerator.same unit in step 3 must be in the numerator.

Note: since the numerator and the denominator are Note: since the numerator and the denominator are equal, the fraction must be equal to 1.equal, the fraction must be equal to 1.

g

mgx

g

g

mgor

mg

g

1

1000

1

0342.0

?1

1000

1000

1

4.4. Multiply the term in step 1 by the fraction in Multiply the term in step 1 by the fraction in step 3.step 3. Since the fraction equals 1, you can Since the fraction equals 1, you can multiply it without changing the size of the multiply it without changing the size of the term.term.

5. Check math by canceling your units.5. Check math by canceling your units.

Convert the following quantities using Convert the following quantities using the following equivalence statements. the following equivalence statements. Show work!Show work!

1 m = 1.094 yd1 m = 1.094 yd 1mile = 1760 yd1mile = 1760 yd 1kg = 2.205lbs1kg = 2.205lbs

1.1. 30.0 m to miles30.0 m to miles

2.2. 1500 yd to miles1500 yd to miles

3.3. 206 miles to m206 miles to m

4.4. 34 kg to lbs34 kg to lbs

5.5. 34 lb to kg34 lb to kg

MatterMatter

• All matter is composed of 100 or so All matter is composed of 100 or so __________________________– A substance that cannot be separated A substance that cannot be separated

into simpler substances by a chemical into simpler substances by a chemical change; simplest type of pure substance.change; simplest type of pure substance.

• The building block of matter is theThe building block of matter is the __________________– The smallest particle of an element that The smallest particle of an element that

retains the chemical identity of the retains the chemical identity of the element.element.

• Atoms can combine to form Atoms can combine to form ______________________

Elements and Compounds = Pure SubstancesElements and Compounds = Pure Substances

• ElementElement= = • CompoundCompound= =

MixturesMixtures

Mixtures can be;Mixtures can be;• HomogeneousHomogeneous= = • HeterogeneousHeterogeneous= =

Classification of MatterClassification of Matter

Properties of MatterProperties of Matter

PhysicalPhysical• Characteristics can Characteristics can

be observed be observed without altering the without altering the identity of the identity of the substancesubstance– VolumeVolume– MassMass– Maleability, Maleability,

ductility, ductility, conductivity etc…conductivity etc…

ChemicalChemical• Characteristics Characteristics

cannot be observed cannot be observed without altering the without altering the identity of the identity of the substancesubstance– FlammabilityFlammability– Tendency to corrodeTendency to corrode– ReactivityReactivity– Etc…Etc…

Changes Matter Can Changes Matter Can Undergo:Undergo:

1.1. Physical ChangePhysical Change::

Solid Solid Liquid Liquid MeltingMelting

Liquid Liquid Gas Gas Boiling or EvaporatingBoiling or Evaporating

Gas Gas Liquid Liquid __________________________

Solid Solid Gas Gas __________________________

Gas Gas Solid Solid __________________________

Liquid Liquid Solid Solid Freezing, solidifying Freezing, solidifying

Changes Matter Can Changes Matter Can Undergo:Undergo:

2.2. Chemical ChangeChemical Change: :

Rusting, rotting, burning, chemical reaction…Rusting, rotting, burning, chemical reaction…

Distinguishing Chemical from Distinguishing Chemical from Physical ChangePhysical Change

1.1. Did the change produce a different Did the change produce a different substance?substance?

2.2. Was there a color change?Was there a color change?3.3. Is there a different density?Is there a different density?4.4. Is there a melting or boiling point change?Is there a melting or boiling point change?5.5. Did something precipitate out of solution?Did something precipitate out of solution?6.6. Did a gas or smoke form?Did a gas or smoke form?

EnergyEnergyRemember: Matter- anything that has mass and takes Remember: Matter- anything that has mass and takes up space. Energy is the other “stuff” of the universe.up space. Energy is the other “stuff” of the universe.

The capacity to do work (the ability to move The capacity to do work (the ability to move or change matter)or change matter)

1. Kinetic- 1. Kinetic-

2. Potential- 2. Potential-

3. Radiant/ electromagenetic- heat* and 3. Radiant/ electromagenetic- heat* and light. light. *We are mainly concerned with heat for this unit.*We are mainly concerned with heat for this unit.

Heat Vs TemperatureHeat Vs TemperatureHeatHeat• Energy due to Energy due to

__________________________________________• Symbol ____Symbol ____• Units: ___________Units: ___________• Does work by Does work by

______________________________________________________________________________________________________________________________

• Flows from hot areas Flows from hot areas to cold areasto cold areas

• CalorimetryCalorimetry

TemperatureTemperature• A measure of A measure of

________________________________________________________________________________________________________________________________________________

• Refers to the intensity Refers to the intensity of heat in an objectof heat in an object

• Symbol TSymbol T• Units: _______________Units: _______________• Change in T = TChange in T = Tff –T –Tii = =

TT• NOT a form of energy NOT a form of energy

but is a predictor of but is a predictor of heat flow heat flow

Heat Vs TemperatureHeat Vs Temperature

• Keep in mind: Keep in mind:

1.1. Objects can be the same Objects can be the same temperature but have different temperature but have different amounts of heat energyamounts of heat energy

2.2. Heat is dependent on MASSHeat is dependent on MASS

Temperature ScalesTemperature Scales• 0 K0 K absolute zeroabsolute zero; all molecular motion ; all molecular motion

stops stops • 0 K 0 K theroretical temperature not yet theroretical temperature not yet

obtained (within a millionth of a degree)obtained (within a millionth of a degree)• Closer to absolute zero Closer to absolute zero atoms move atoms move

more and more slowly – much more more and more slowly – much more difficult to remove heatdifficult to remove heat

• Sig figs and temperature: because the Celsius temperature is a Sig figs and temperature: because the Celsius temperature is a continuum with both positive and negative values, a temperature continuum with both positive and negative values, a temperature measurement of 0measurement of 000C has 1 sig fig (0.1C has 1 sig fig (0.100C = 2 sig figs)C = 2 sig figs)

Temperature Scale Temperature Scale ConversionsConversions

Significant Temperatures for Significant Temperatures for Phases of WaterPhases of Water

ooCC KK ooFF

Water Water melts/ melts/ freezesfreezes

Water boils/ Water boils/ condensescondenses

Kinetic Molecular Theory*Kinetic Molecular Theory* 1.1.

(atoms / molecules)(atoms / molecules)

2.2.

3.3.

• The basic principles of KMT are theoretical The basic principles of KMT are theoretical and begin to break down under certain and begin to break down under certain circumstancescircumstances KMT is better at KMT is better at describing matter in higher energy states describing matter in higher energy states (gases, for example)(gases, for example)

States/ Phases of MatterStates/ Phases of Matter

State

Shape and

volume

Distance btw

molecules

Entropy= a

measure of disorder/

randomness

Motion

SolidSolid OrganizedOrganized No random No random motion motion

(vibrating (vibrating in place)in place)

LiquidLiquid Much Much disorderdisorder

Some Some random random motion motion

(flowing)(flowing)

gasgas Most Most disorderdisorder

Completely Completely random random motion motion

(diffusion)(diffusion)

CalorimetryCalorimetry• Physical and chemical changes are normally Physical and chemical changes are normally

accompanied by energy changes.accompanied by energy changes.• Energy changes in a laboratory setting are Energy changes in a laboratory setting are

measured using a calorimeter.measured using a calorimeter.

Types of Energy ChangesTypes of Energy Changes

• If heat is consumed If heat is consumed during the change, during the change, then the then the process/change/reactiprocess/change/reaction is said to be on is said to be ______________________________________..

• If heat is produced If heat is produced during a change, during a change, then the then the process/change/reaprocess/change/reaction is said to be ction is said to be ________________________________..

Law of Conservation of EnergyLaw of Conservation of Energy• Within a closed system, energy Within a closed system, energy

transforms from one type to another.transforms from one type to another.• ____________________________________________________________________________..ExampleExample: electricity lights a bulb: : electricity lights a bulb:

resistance builds up in the tungsen wire, resistance builds up in the tungsen wire, it glows and gives off light and heat; the it glows and gives off light and heat; the total energy in the heat and light = the total energy in the heat and light = the energy in the electricity.energy in the electricity.

ExampleExample: when heat is added to water on a : when heat is added to water on a hot plate, that heat energy is absorbed hot plate, that heat energy is absorbed by the water molecules, which move by the water molecules, which move faster and faster (increased kinetic faster and faster (increased kinetic energyenergy higher temperature) higher temperature)

Law of Conservation of MatterLaw of Conservation of Matter• Matter can only be transformed during Matter can only be transformed during

chemical and physical changes.chemical and physical changes.• ___________________________________________.___________________________________________.ExampleExample: when ice melts to make water during : when ice melts to make water during

a phase changea phase changeExampleExample: when two chemicals are mixed: when two chemicals are mixed*On our large scale, we see matter and energy as separate, but *On our large scale, we see matter and energy as separate, but

matter and energy interconvert at the subatomic level matter and energy interconvert at the subatomic level according to Einstein’s Theory of Relativity E=mcaccording to Einstein’s Theory of Relativity E=mc22))

Calorie ProblemsCalorie ProblemsTheoretical values for energy changes during the heating or Theoretical values for energy changes during the heating or cooling of a substance, or during a phase change, can be cooling of a substance, or during a phase change, can be calculated using three basic equations.calculated using three basic equations.

DURING HEATING OR DURING HEATING OR COOLINGCOOLING

c = specific heat for c = specific heat for water = 4.18 J/gwater = 4.18 J/gooCC

m = mass of samplem = mass of sample

T = change in T = change in temperature of temperature of

sample in sample in ooCC

DURING A PHASE CHANGEDURING A PHASE CHANGE (freezing/ melting)(freezing/ melting)

(evap / condense)(evap / condense)

M = mass of sampleM = mass of sample

HHff = heat of fusion (for = heat of fusion (for water = 334 J/g)water = 334 J/g)

HHvv = heat of vaporization = heat of vaporization (for water = 2260 J/g)(for water = 2260 J/g)

Why do we add propylene glycol Why do we add propylene glycol (antifreeze) to our car’s radiators?(antifreeze) to our car’s radiators?

The value of Q for any The value of Q for any substance can be substance can be calculated, but note that calculated, but note that each substance has each substance has unique values for specific unique values for specific heat capacity (c), heat of heat capacity (c), heat of fusion (Hfusion (Hff), and heat of ), and heat of vaporization (Hvaporization (Hvv). Think ). Think about it: it’s easier to raise about it: it’s easier to raise the temperature of some the temperature of some substances than others.substances than others.

• High specific heat capacity (c)High specific heat capacity (c) = a = a large amount of energy must be large amount of energy must be added in order to increase the added in order to increase the temperature.temperature.– Water(l) = 4.18 J/(g•K)Water(l) = 4.18 J/(g•K)

• Low specific heat capacity (c)Low specific heat capacity (c) = a = a small amount of energy must be small amount of energy must be added in order to increase the added in order to increase the temperature.temperature.– Iron(s) = 0.129 J/(g•K)Iron(s) = 0.129 J/(g•K)

Q = mcQ = mcTT

• How much heat is required to raise How much heat is required to raise the temperature of 10.0 g of water the temperature of 10.0 g of water from 5from 5ooC to 25.0C to 25.0ooC?C?

• What will be the temperature What will be the temperature change if 418 J of heat are added change if 418 J of heat are added to 25 g of water?to 25 g of water?

Q = mHQ = mHff

How much heat is needed to melt How much heat is needed to melt 5.0 g of water?5.0 g of water?

Q = mHQ = mHvv

How much water can be vaporized How much water can be vaporized by 3135 Joules?by 3135 Joules?