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What is Chemistry? The study of the composition, structure,

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Presentation on theme: "What is Chemistry? The study of the composition, structure,"— Presentation transcript:

1 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

2 Categories of Science Concerned with living things Concerned with non
i. Biological – ii. Physical - Concerned with non living things

3 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.

4 Branches of Chemistry Analytical – 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.

5 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

6 Physical Properties Properties – characteristics enabling us to distinguish differences in matter. Physical properties – can be observed or measured 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.

7 Physical Change A physical change is the changing of a substance does not alter the chemical composition. It can change states. Cutting, grinding, expanding

8 States of Matter Neither definite shape or volume
Solid Liquid Gas Plasma Definite shape & volume Definite volume, not shape Neither definite shape or volume Gaseous system with ions

9 Chemical Properties/Changes
Alters chemical identification. Chemical reaction- Reactants -> Products Reactants are the substances you start off with And 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

10 Physical or Chemical ? Physical Chemical

11 Classification of Matter
Mixtures – retain own composition & properties. Heterogeneous – Not uniform Homogeneous – Uniform Pure substance – has a fixed composition. Are either compd. or elements. Elements – is on the periodic chart. (Simplest form) compounds – chemically combined ex. NaCl Every sample has exactly the same characteristic prop. Every sample has exactly the same composition. ex. H2O % H, % O

12 Distillation Method for physically separating a mixture of liquids or a solid dissolved in a liquid

13 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.

14 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.

15 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

16 Periodic Table Families or Groups – Vertical columns, # 1 – 18
Periodic Table Families or Groups – Vertical columns, # 1 – 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. Semiconductors Noble Gases – unreactive gases.

17 Symbols for elements IUPAC – International Union of Pure & Applied Chemistry O – oxygen H – N - Na - Sb stibium – antimony Cu cuprum – copper Au Aurum – gold Ag Argentum – silver Na Natrium – sodium

18 Scientific method- logical approach to solutions of problems
Parts – Observations – collecting data Quantitative & Qualitative Generalizing – Organize, analyze, & classify Hypothesis – testable statement Testing - experimenting Theory – Explains why things occur. Broad generalization that explains a body of facts or phenomena. Model Law – Describes a variety of scientific behavior

19 Types of Data Qualitative – descriptive nonnumeric results
Quantitative – gives definite, usually numeric, results Number Unit

20 Graphing Directly proportional Inversely proportional Types of Graphs:
Title graph Label axis – numbers & units Choose Scale Independent variable – X – axis (Usually Time) Dependent variable – Y – axis Plot Points Draw Best Fit Line Directly proportional Inversely proportional Dividing 1 by the other If product is constant gives a constant value Types of Graphs: Line graph Bar graph Pie/ circle graph

21 Pie Graph Data Gender # of ppl Elderly 27 Women 13 Men 6 Children 15
To get percentages: Gender # of ppl Elderly 27 Women 13 Men 6 Children 15 Total 61 Get part / whole # X 100 44.3 % Elderly: 27/61 X 100 = 21.3 % 9.8 % 24.6 % Women Men Children Total 100 % Degrees: = X 159.5 °

22 Units of Measurement-SI system
Standards of Measurement SI – International System of Units 1. Based on units of ten, makes it easier to use 2. 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 L Time t second s Temperature T kelvin K Amount of substance n mole mol

23 SI Units Kilo hecto deka base deci centi milli
King Henry Died by Drinking Chocolate Milk There are 1000 base units in one kilo There are 1000 milli in one base unit

24 Derived SI Units D = 10.8 g 4.0 cm3 D = 2.7 g/cm3 D = m/v
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 = 10.8 g 4.0 cm3 D = 2.7 g/cm3 D = m/v

25 Derived Units Density D = 453.3 g 123.0 ml
What is the density of a block of marble with a mass of g and a Volume of ml? D = m v D = g 123.0 ml D = 3.685g/ml

26 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.

27 Precise Precise & Accurate Neither


29 Percent Error Accepted value - Experimental value Percent error = accepted value. X 100 What is the percent error for a mass measurement of 17.7 g, given that the correct value is 21.2 g? % error = g g 21.2 g 16.5 % error X 100 =

30 Significant Figures All digits known plus one final digit
Measurements from equipment

31 Counting Significant Figures
All non-zero numbers are significant Zeros * Leading zeros – never * Captive zeros – Always * Trailing zeros * With a decimal – count * Without a decimal – don’t count

32 3 Questions for Zeros Is there a number in front? Is it trapped?
No – Not significant Yes – May be… go to #2 & #3 Is it trapped? Yes - It is significant Is there a Decimal? No – Not Significant Yes – It is significant

33 Counting Significant Figures
3440. cm 910 m L kg km

34 Calculations – multiplication & Division
* The answer is rounded off to the same number of significant figures as in the measurement with the fewest sig. Fig. 13.0 ml * ml X ml = * g / 0.04 cm3 = 62.5 60 g/cm3

35 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 ____ 55.08 – = 55.075 . \ 311.67 Rounding 312. Less than 5 = stay the same More than 5 = increase one If 5 = if odd increase by one if even leave it alone

36 | | | Scientific Notation 4.6 X 10 –4 cm 2.4 X 10 -1 g 5.02 X 10 4 m
Must be a number from 1 to 9 !!!!!!!!! | * g (2 significant figures) 2.4 X g | * m (3 significant figures) 5.02 X 10 4 m | * cm (2 significant figures) 4.6 X 10 –4 cm

37 SI - Prefixes Kilo, hecto, deka, Base, deci, centi, milli
Grams, liters, meters Kilo, hecto, deka, Base, deci, centi, milli King Henry Dances barbarically down center maine King Henry Died by drinking chocolate milk 1.0 Kg = g 1.0 hg = 100 g 1.0 dag = 10 g Grams, liters, meters 10 dg = 1.0 g 100 cg = 1.0 g 1 000 mg = 1.0 g

38 Chemistry Dominoes Rules
Don’t slam or throw dominoes Take turns Quickly get quiet when I call for your attention. To End The Game The player who makes the connection to the last domino wins Count up the number of dominoes left on the table. Each domino is 1 point. Award the winner the points left on the table.

39 Game Play Each payer draws 1 domino to see who plays first (high domino) Shuffle (wash) the dominoes Each player draws 5 dominoes Player 1 plays a number blank (if no number blank, draw) This is the starting domino Player 2 plays a number blank. (if no number blank, draw) This is the end domino. For the rest of the game, players play dominoes that will cancel the top number on the domino If you can not play, draw 1 domino. This domino may be played.

40 Factor Label ________|__________ Draw your T
Write conversion-equivalent statements to… Cancel out units Top – Multiply, Bottom – Divide The mass of a quarter is 10.4g, how many milligrams is that? ________|__________ mg 10.4g 1000 = mg | g 1.0

41 Factor Label km Express a distance of 28. Meters in centimeters
and then in kilometers. 28. m cm 100 = 2,800 cm m 1.0 28. m km 1.0 = km 1000 m

42 Factor Label 3.2 X 10 7sec * 1.0 year = __________________ seconds
1.0 yr 365 days = 31,536,000 sec 24 hrs 60 min 60 sec 1 yr 1 hr 1 min 1 day 3.2 X 10 7sec

43 Factor Label Dimensional Analysis
1. How many kilograms are in 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?

44 Quiz 25.3 ft = _______________ mm 7.5 mg = ______________ hg
12.5 kl = _______________ ml 5.4 X 10 –6 km= _________ mm 3.0 L = ________________ cm3 25.0 weeks = ____________ sec

45 Heat & Temperature Temperature – 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

46 Units of Temperature Celsius Kelvin Fahrenheit

47 Heat Transfer Convection – transfer of heat by the motion of particles in a fluid Conduction – transfer of heat through matter by colliding particles Radiation – transfer of energy in the form of electromagnetic waves Heat always moves from high energy to low energy. (hot to cold)

48 Examples Hot air balloons Hot water and cold water mixing Heating a pan Boiling water

49 Units of Heat Joule Calorie 1.0 cal = 4.180 joules
The SI unit of heat energy as well as all Other forms of energy. Calorimeter – measures the energy absorbed or released as heat in a chemical or physical change. 1.0 cal = joules

50 Heat Capacity Amount of heat energy needed to raise the temperature of a sample 1oC

51 Specific Heat Q = m X Cp X DT
Amount of heat energy needed to raise the temperature of 1g of a sample 1oC. Equation Q = m X Cp X DT UNITS Joules = J Grams = g J/g* oC oC Q = energy lost/ gained M = mass Cp = specific heat DT = delta T = change in temp.

52 Problems 1oC to 41oC and was found to have absorbed
. A 4.0 g sample of glass was heated from 1oC to 41oC and was found to have absorbed 32 J of heat. What is the specific heat of this type of glass?

53 Problems 1oC to 41oC and was found to have absorbed
. A 4.0 g sample of glass was heated from 1oC to 41oC and was found to have absorbed 32 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 Cp = 0.20J/goC

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

55 How much heat did the same glass sample gain when it was heated from
problem How much heat did the same glass sample gain when it was heated from 41oC to 71oC? Q = m Cp DT Q=(4.0g)(0.20J/goC)(30oC) Q=24J m=4.0g DT=71oC-41oC=30oC Cp=0.20J/goC

56 Quiz 4.5 m = __________ km 899.9 ml = ________ L .54 kg = __________cg
4.5 ml = __________cm3 D = 2.45 g/ml, mass = 12.5 g vol. = ? Vol = 25.5 ml, mass = 32.3 g D = ? D = 3.4 g/cm3 vol = 1.5 cm mass = ? List the things that a graph must contain (at least 4 things)

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