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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)