What is Chemistry?

The study of the composition, structure, & properties of substances and changes it undergo.

A chemical is any substance that has a part in a chemical rxn or is produced. Practical Uses

Clothing – synthetic fabric Nonstick cookware - Teflon Pharmaceuticals - medications

Categories of Science

i. Biological –

ii. Physical - Concerned with nonliving things

Concerned with livingthings

Branches of Chemistry Organic – Study of living - contains

carbon.

Inorganic – study of non-living – no carbon.

Physical – study of properties, transformations, and interrelationship of energy and matter.

Branches of ChemistryAnalytical – identification of substances & study of

composition of materials

Biochemistry – Process that occurs in living things connects biological processes w/ chemical processes.

Theoretical – the use of math & computers to understand the principles behind observed chemical behavior and to design and predict the properties of new compounds.

Matter & Its Properties

Atom – the smallest particle of an element that retains the properties of that element.

Elements – A substance that cannot be changed into a simpler substance under normal lab conditions

Physical PropertiesProperties – characteristics

enabling us to distinguish differences in matter.

Physical properties – can be observed ormeasured w/o changing the identity of material

Extensive physical properties – depends on the amount of matter. (mass, length, volume).

Intensive physical properties – does not depend on mass, melting pt, boiling pt, density, color, ductile,

malleable, crystal shape, etc.

Physical ChangeA physical change is the

changing of a substance does not alter the chemical composition.

It can change states.

Cutting, grinding, expanding

States of MatterSolid

Liquid

Gas

Plasma

Definite shape & volume

Definite volume, not shape

Neither definite shape or volumeGaseous system with ions

Chemical Properties/ChangesAlters chemical identification.

Chemical reaction- Reactants -> Products

Reactants are the substances you start off withAnd they then react and yields a new product.

Ex. Wood burning, matches, letting milk stand so it can turn sour, iron rust, tarnishing silver.

Na + Cl NaCl

Charcoal + O2 CO2

Fe + O2 Fe2O3

Physical or Chemical ? Physical

Chemical

Chemical

Physical

Classification of MatterMixtures – retain own

composition & properties.Heterogeneous – Not uniformHomogeneous – Uniform

Elements – is on the periodic chart. (Simplest form)compounds – chemically combined ex. NaCl

Pure substance – has a fixed composition. Are either compd. or elements.

1. Every sample has exactly the same characteristic prop.2. Every sample has exactly the same composition.

ex. H2O 11.2 % H, 88.8 % O

DistillationMethod for physically

separating a mixture of liquids or a solid dissolved in a liquid

Matter & Energy

a. Matter – Occupies space and has mass.

Inertia – Resistance to change in motion.

Weight Vs. Mass -

Weight is the measure of gravitational pull.

Mass is quantity of matter.

Law of conservation of mass:

Mass is neither created nor destroyed.

Energy – Ability to do work or cause change

Types of Energy -

Kinetic Energy – in the form of motion

Potential Energy – Stored energy depends on composition or position

Law of Conservation of Energy

Energy can change form, but it cannot be Created nor destroyed under ordinary cond.

Energy and changes in matter Exothermic – produce

heat. Energy is released in the form of heat.

H + O H2O + Heat

Endothermic – gain heat. Energy,in a form of heat, is absorbed.

Ex. Melting ice

Periodic TableFamilies or Groups – Vertical columns, # 1 – 18 . Elements share properties.Periods – horizontal rows

Metals – Good conductors of heat & electricity.

Shiny, luster, malleable, ductile, tensil.

Non-Metals – Poor conductors of heat/electricity.

Metalliods – Share characteristics of metals & nonmetals.

SemiconductorsNoble Gases – unreactive gases.

Symbols for elements

IUPAC – International Union of Pure & Applied Chemistry

O – oxygen H – N - Na -

Sb stibium – antimonyCu cuprum – copperAu Aurum – goldAg Argentum – silverNa Natrium – sodium

Scientific method- logical approach to solutions of problems

Parts – • Observations – collecting data

Quantitative & QualitativeGeneralizing – Organize, analyze, & classify

Hypothesis – testable statement

Law – Describes a variety of scientific behavior

Theory – Explains why things occur. Broad generalization that explains a body of facts or phenomena. Model

Testing - experimenting

Types of DataQualitative – descriptive nonnumeric

resultsQuantitative – gives definite, usually

numeric, resultsNumberUnit

Graphing• Title graph • Label axis – numbers & units• Choose Scale Independent variable – X – axis (Usually Time) Dependent variable – Y – axis• Plot Points• Draw Best Fit Line

Line graph Bar graph Pie/ circle graphTypes of Graphs:

Directly proportional Inversely proportional Dividing 1 by the other If product is constant gives a constant value

Pie Graph Data

Gender # of pplElderly 27Women 13

Men 6

Children 15Total 61

To get percentages:

Get part / whole # X 100

Elderly: 27/61 X 100 = 44.3 %

WomenMenChildrenTotal

21.3 % 9.8 %24.6 %

100 %

Degrees: 44.3 = X 100 360

159.5 °

Standards of Measurement

SI – International System of Units 1960

Units of Measurement-SI system

1. Based on units of ten, makes it easier to use2. Used world wide

SI Base Units - (pg 34)Fundamental SI Units Qty Symbol Unit name Unit abbreviation Length l Meter m Mass m Kilogram kg Volume V Liter LTime t second sTemperature T kelvin KAmount of substance n mole mol

SI Units

Kilo hecto deka base deci centi milli

1000 100 10 1 0.1 0.01 0.001

King Henry Died by Drinking Chocolate Milk

There are 1000 base units in one kilo

There are 1000 milli in one base unit

Derived SI Units Density = Mass/volume

Volume = l X w X h

Find the density of a piece of aluminum w/ a volume of 4.0 cm3 and a mass of 10.8 g.

D = m/vD = 10.8 g 4.0 cm3

D = 2.7 g/cm3

Derived UnitsDensity

What is the density of a block of marble with a mass of 453.3 g and a Volume of 123.0 ml?

D = m v

D = 3.685g/mlD = 453.3 g 123.0 ml

Accuracy Vs. Precision

ACCURACY – Refers to the agreement of a particular value with the true value.

PRECISION – Refers to the degree of agreement among several elements of the same quantity.

Precise & Accurate Precise

Neither

Percent Error

What is the percent error for a mass measurement of 17.7 g, given that the correct value is 21.2 g?

Accepted value - Experimental valuePercent error =

accepted value.

% error = 21.2 g - 17.7 g

21.2 g

X 100

X 100 = 16.5 % error

Significant FiguresAll digits known plus one final digit

Measurements from equipment

Counting Significant FiguresAll non-zero numbers are

significant

Zeros * Leading zeros – never * Captive zeros – Always * Trailing zeros

* With a decimal – count* Without a decimal – don’t count

3 Questions for Zeros

1. Is there a number in front? No – Not significant Yes – May be… go to #2 & #3

2. Is it trapped? No – Not significant Yes - It is significant

3. Is there a Decimal? No – Not Significant Yes – It is significant

Counting Significant Figures

1. 28.6 g 2. 3440. cm3. 910 m4. 0.04604 L5. 0.0067000 kg6. 0000900 km

Calculations – multiplication & Division

* The answer is rounded off to the same number of significant figures as in the measurement with the fewest sig. Fig.

* 6.43 ml X 2.015 ml = 12.95 645 13.0 ml

* 2.50 g / 0.04 cm3 = 62.5 60 g/cm3

Calculations – Addition & Subtraction

Results should be rounded off so that the final digit is in the same place as the number with the fewest digits.

213.67+ 98.____ 311.67

\

. \312.

78.945 – 23.87 = 55.075 55.08

Rounding Less than 5 = stay the sameMore than 5 = increase one

If 5 = if odd increase by one if even leave it alone

Scientific Notation

* 0 . 2 3 5 6 g (2 significant figures)

2.4 X 10 -1 g|

* 5 0 1 7 8 m (3 significant figures)|5.02 X 10 4 m

* 0.0 0 0 4 5 5 9 cm (2 significant figures)

4.6 X 10 –4 cm

|

Must be a number from 1 to 9 !!!!!!!!!

SI - Prefixes

1.0 Kg = 1 000 g 1.0 hg = 100 g 1.0 dag = 10 gGrams, liters, meters 10 dg = 1.0 g 100 cg = 1.0 g1 000 mg = 1.0 g

Kilo, hecto, deka, Base, deci, centi, milliGrams, liters, meters

King Henry Dances barbarically down center maineKing Henry Died by drinking chocolate milk

Chemistry Dominoes Rules 1. Don’t slam or throw dominoes2. Take turns3. Quickly get quiet when I call for your

attention.

To End The Game4. The player who makes the connection to

the last domino wins5. Count up the number of dominoes left on

the table. Each domino is 1 point.6. Award the winner the points left on the

table.

Game Play1. Each payer draws 1 domino to see who plays

first (high domino)

2. Shuffle (wash) the dominoes

3. Each player draws 5 dominoes

4. Player 1 plays a number blank (if no number blank, draw) This is the starting domino

5. Player 2 plays a number blank. (if no number blank, draw) This is the end domino.

6. For the rest of the game, players play dominoes that will cancel the top number on the domino

7. If you can not play, draw 1 domino. This domino may be played.

Factor Label• Draw your T • Write conversion-equivalent statements to…• Cancel out units • Top – Multiply, Bottom – Divide

1. The mass of a quarter is 10.4g, how many milligrams is that?

________|__________10.4g

| g

mg = 10400 mg1.0

1000

Factor Label•Express a distance of 28. Meters in centimeters and then in kilometers.

28. m

m

cm = 2,800 cm

28. m

m

km = 0.028 km

1.0

100

1.0

1000

Factor Label* 1.0 year = __________________ seconds

1.0 yr

1 yr

365 days

1 day

24 hrs

1 hr

60 min

1 min

60 sec = 31,536,000 sec

3.2 X 10 7sec

Factor Label Dimensional Analysis

1. How many kilograms are in 1.428 grams?

2. How many liters are in 13.4 kL?

3. A pencil is 7.5 centimeters, how many millimeters?

4. You want to order a bicycle with a 225 mm frame, but the sizes in the catalog are given only in inches, what should you order?

5. A student enters a 10.0 km run. How many yards is the run?

Quiz

25.3 ft = _______________ mm7.5 mg = ______________ hg12.5 kl = _______________ ml5.4 X 10 –6 km= _________ mm3.0 L = ________________ cm3

25.0 weeks = ____________ sec

Heat & TemperatureTemperature – measure of average

kinetic energy

Heat – sum of kinetic energy in all of the particles in a sample

A tub of boiling water & a cup full of boiling water

Units of Temperature

CelsiusKelvinFahrenheit

Heat TransferConvection – transfer of heat by

the motion of particles in a fluidConduction – transfer of heat

through matter by colliding particlesRadiation – transfer of energy in

the form of electromagnetic wavesHeat always moves from high

energy to low energy. (hot to cold)

Examples

Hot air balloonsHot water and cold water

mixing Heating a panBoiling water

Units of HeatJoule

Calorie

The SI unit of heat energy as well as allOther forms of energy.

Calorimeter – measures the energy absorbed or released as heat in a chemical or physical change.

1.0 cal = 4.180 joules

Heat CapacityAmount of heat energy needed to raise

the temperature of a sample 1oC

Specific HeatAmount of heat energy needed to raise

the temperature of 1g of a sample 1oC.Equation

Q = m X Cp X DT

Q = energy lost/ gained M = massCp = specific heatDT = delta T = change in temp.

UNITS Joules = JGrams = gJ/g* oC oC

Problems

. A 4.0 g sample of glass was heated from 1oC to 41oC and was found to have absorbed32 J of heat. What is the specific heat of this type of glass?

Problems

ΔT m

QCp

. A 4.0 g sample of glass was heated from 1oC to 41oC and was found to have absorbed32 J of heat. What is the specific heat of this type of glass?

Q = m Cp DT

m=4.0g

DT=41oC-1oC=40oC

Q=32J

C)(4.0g)(40

32JC

op

Cp = 0.20J/goC

problemHow much heat did the same glass sample gain when it was heated from 41oC to 71oC?

problemHow much heat did the same glass sample gain when it was heated from 41oC to 71oC?

Q = m Cp DT

m=4.0g

DT=71oC-41oC=30oC

Cp=0.20J/goC

Q=(4.0g)(0.20J/goC)(30oC)

Q=24J

Quiz1. 4.5 m = __________ km2. 899.9 ml = ________ L3. .54 kg = __________cg4. 4.5 ml = __________cm3

5. D = 2.45 g/ml, mass = 12.5 g vol. = ?6. Vol = 25.5 ml, mass = 32.3 g D = ?7. D = 3.4 g/cm3 vol = 1.5 cm3 mass = ?8. List the things that a graph must contain (at least 4 things)