Outlin e Outlin e Unit 1 Introduction to Chemistry Internet web site: www.unit5.org/chemistry PowerPoint Presentation by Mr. John Bergmann Safety Basic Safety Rules #1 Rule: Use common sense. Others:

No horseplay. No unauthorized experiments. Handle chemicals/glassware with respect. Safety Features of the Lab safety shower fire blanket fire extinguisher eye wash fume hood circuit breaker switch Material Safety Data Sheet (MSDS) -- gives information about a chemical

-- lists Dos and Donts; emergency procedures Chemical Exposure acute exposure a one-time exposure causes damage e.g., reaction to drugs or medication chronic exposure damage occurs after repeated exposure e.g., smoking,

asbestos LD50 the lethal dosage for 50% of the animals on which the chemical is tested There are various ways an LD50 can be expressed. For example, acetone has the following LD50s: ORL-RAT LD50: 5,800 mg/kg IHL-RAT LD50: 50,100 mg/m3-h SKN-RBT LD50: 20 g/kg Example Chemical A: LD50 = 3.2 mg/kg Chemical B: LD50 = 48 mg/kg

Which is more toxic? Chemical A is more toxic because less of it proves fatal to half of a given population. Science The Functions of Science pure science the search for knowledge; facts e.g., aluminum strong lightweight good conductor applied science

using knowledge in a practical way Science attempts to establish cause-effect relationships. risk-benefit analysis weigh pros and cons before deciding Because there are many considerations for each case, 50/50 thinking rarely applies. How does scientific

knowledge advance? 1. curiosity 2. good observations 3. determination 4. persistence The Scientific Method ** Key: Be a good observer. observation uses the five senses inference involves a judgment

or assumption Types of Data Observations are also called data. qualitative data -- descriptions e.g., clear liquid quantitative data -- measurements e.g., 55 L or 83oC Parts of the Scientific Method Identify an unknown. Make a hypothesis: a testable prediction

Repeatedly experiment to test hypothesis. procedure: order of events in experiment (i.e., a recipe) variable: any factor that could influence the result A Scientific Experiment Experiments must be controlled: they must have two set-ups that differ by only one variable conclusion: must be based on the data Scientific Law vs. Scientific Theory

law: states what happens does not -change never -violated law of gravity, -- e.g., laws of conservation theory: tries to explain why or how something happens -- based on current evidence -- e.g., Theory of Gravity, Atomic Theory Phlogiston Theory of Burning

1. Flammable materials contain phlogiston. 2. During burning, phlogiston is released into the air. 3. Burning stops when object is out of phlogiston, or the surrounding air contains too much phlogiston. (superceded by combustion theory of burning) Chemistry The Beginning early practical chemistry: household goods, weapons, soap, wine, basic medicine The Greeks believed there

were four elements. D ___ earth ___ D wind ~ water

D fire Alchemy (~500 1300 C.E.) the quest for the Philosophers Stone (the elixir, the Sorcerers Stone) Allegedly, this substance would turn cheap metals into gold. Alchemical symbols for substances GOLD SILVER COPPER

IRON . .. ... .... ..... SAND transmutation: changing one substance into another Philosophers Stone

COPPER GOLD we cannot In ordinary chemical reactions transmute elements into different elements. Alchemy was practiced in many regions of the world, including China and the Middle East. Alchemy arrived in western Europe around the year 500 C.E. Modern chemistry evolved from alchemy.

Contributions of alchemists: experimental techniques new glassware information about elements developed several alloys What is Chemistry? the study of matter

and its changes Areas of Chemistry organic the study of carboncontaining compounds inorganic studies everything except carbon e.g., compounds containing metals biochemistry the chemistry of living things physical

measuring physical properties of substances e.g., the melting point of gold Careers in Chemistry research (new products) production (quality control)

development (manufacturing) chemical sales software engineering teaching The skills you will develop by an earnest study of chemistry will help you in any career field. The Scope of Chemistry bulk chemical manufacturing acids, bases, fertilizers **sulfuric acid (H2SO4) = #1 chemical petroleum products fuels, oils, greases, asphalt pharmaceuticals

1 in 10,000 new products gets FDA approval synthetic fibers nylon, polyester, rayon , spandex All fields of endeavor are affected by chemistry. Government Regulation of Chemicals worker OSHA environment EPA The government

regulates chemicals to protect the FDA USDA FAA CPSC consumer Manipulating Numerical Data Graphs Bar Graph shows how many of something are in each category Chemistry Grades

# of students 10 8 6 4 2 0 A B C D

F Pie Graph shows how a whole is broken into parts Percentage of Weekly Income Entertainment (40%) Food (25%) Clothing (20%) Savings (15%) Line Graph shows continuous change Stock Price over Time

Share Price ($) 60 50 40 30 20 10 0 Jan Feb Mar Apr

Month In chemistry you will always use a line graph. Elements of a good line graph Temp. v. Vol. for a Gas at Constant Pressure 2. axes labeled, with units 3. neat 4. use the available space Volume (L)

1. title 10 9 8 7 6 5 4 3 2 1 0 120

140 160 180 200 Temp. (K) 220 240 Essential Math of Chemistry

Scientific Notation -- used to express very large or very small numbers, and/or to indicate precision (i.e., to maintain the correct number of significant figures) Form:(# from 1 to 9.999) x 10exponent 800 = 8 x 10 x 10 = 8 x 102 2531 = 2.531 x 10 x 10 x 10 = 2.531 x 103 0.0014 = 1.4 10 10 10 = 1.4 x 103 Put in standard form.

1.87 x 105 = 0.0000187 3.7 x 108 = 370,000,000 7.88 x 101 = 78.8 2.164 x 102 = 0.02164 Change to scientific notation. 12,340 = 1.234 x 104 0.369 = 3.69 x 101 0.008 = 8 x 103 1,000,000,000 = 1 x 109 6.02 x 1023 = 602,000,000,000,000,000,000,000 Using the Exponent Key EE EXP The EE or EXP or E key means times 10 to the

How How to to type type out out 6.02 6.02 xx10 102323:: 6 0 . 2 EE

2 3 not WRONG! 6 0 . 2

yx 2 3 WRONG! or 6 . 0 2

x 1 and not 6 . 0 EE 2 3

TOO MUCH WORK. 0 2 x 1 0 yx 2

3 Also, know when to hit your () sign. (before the number, after the number, or either one) 1.2 x 105 2.8 x 10 19 Type this calculation in like this: 1

. 2 EE 5 2 . 8 EE

1 9 = Calculator gives 4.2857143 15 or 4.2857143 E15 This is NOT written 4.315 But instead is written 4.3 x 109 or 4.3 E 9

7.5 x 106 (8.7 x 1014) = 6.5 x 1019 4.35 x 106 (1.23 x 103) = 5.35 x 103 or 5350 5.76 x 1016 9.86 x 104 = 8.8 x 1011 x 3.3 x 1011 = 5.84 x 1013 2.9 x 1023 Essential Math of Chemistry

Units must be carried into the answer, unless they cancel. 5.2 kg (2.9 m) = 0.64 kg-m (18 s)(1.3 s) s2 4.8 kg (23 s) (18 s)(37 s) = 0.57 kg s Solve for x. x+y=z

x and y are connected by addition. Separate them using x + y = z subtraction. In general, use y y opposing functions to separate things. The +y and y cancel on the left, leaving us with

x=zy Numerical Example Solve for x. x 24 = 13 x and 24 are connected by subtraction. Separate them using the opposite function: addition. x 24 = 13 +24 +24 The 24 and +24 cancel

on the left, leaving us with x = 37 Solve for x. x and k are connected by multiplication. Separate them using the opposite function: division. The two ks cancel on the right, leaving us with F=kx

() () __ 1 __ 1 F=kx k k (or) F=kx k k __ F

x= k Numerical Example Solve for x. x and 7 are connected by multiplication. Separate them using the opposite function: division. The two 7s cancel on the right, leaving us with 8=7x ()

() 1 1 __ __ 8=7x 7 7 (or) 8=7x 7 7 __ 8 x=

7 Solve for x. One way to solve this is to cross-multiply. Then, divide both sides by TR. The answer is ___ BA = ___ TR x H BAH = xTR

( ) ( ) ___ 1 BAH = xTR ___ 1 TR TR BAH x = ___ TR Solve for T2, where

P P 1V1 2V2 ____ ____ = T1 T2 P1 = 1.08 atm P2 = 0.86 atm V1 = 3.22 L V2 = 1.43 L T1 = 373 K

( ) ( ) ____ 1 P V T = P V T ____ 1 1 1 2 2 2 1 P1V1 P1V1 P2V2T1 ______ T2 =

P1V1 (0.86 atm)(1.43 L)(373 K) _____________________ T2 = = 132 K (1.08 atm)(3.22 L) SI Prefixes kilo- (k) 1000 1 deci(d) /10 centi- (c) milli-

/100 1 (m) /1000 1 Also, 1 mL = 1 cm3 and 1 L = 1 dm3 Conversion Factors and

Unit Cancellation How many cm are in 1.32 meters? equality: 1 m = 100 cm (or 0.01 m = 1 cm) conversion factors: 1m ______ 100 cm or (

100 cm ______ 1m ) 100 cm = 132 cm 1.32 m ______ 1m We use the idea of unit cancellation to decide upon which one of the two conversion factors we choose. How many m is 8.72 cm? equality: 1 m = 100 cm

conversion factors: 1m ______ 100 cm or ( 100 cm ______ 1m )

1m 8.72 cm ______ = 0.0872 m 100 cm Again, the units must cancel. How many kilometers is 15,000 decimeters? ( )( 1m 15,000 dm ____ 10 dm

) 1 km ______ = 1.5 km 1,000 m How many seconds is 4.38 days? ( )( 24 h 4.38 d ____ 1d

)( ) 60 min _____ 1h 60 s ____ = 378,432 s 1 min If we are accounting for significant figures, we would change this to 3.78 x 105 s

Simple Math with Conversion Factors Find area of rectangle. 4.6 cm A=L.W = (4.6 cm)(9.1 cm) 9.1 cm = 42 cm2. cm Convert to m2.

cm.cm 1m 42 cm2 ______ 100 cm ( ) = 0.0042 m2 ( ) = 4200 mm2

10 mm Convert to mm2. 42 cm2 ______ 1 cm 2 2 For the rectangular solid: Length = 14.2 cm Width = 8.6 cm Height = 21.5 cm Find volume. V=L.W.H = (14.2 cm)(8.6 cm)(21.5 cm)

= 2600 cm3 Convert to mm3. ( ) 10 mm 2600 cm3 ______ 1 cm 3 = 2,600,000 mm3 = 2.6 x 106 mm3

mm and cm differ by a factor of. 10 mm2 cm2 . 100 mm3 cm3

. 1000 Basic Concepts in Chemistry chemical: any substance that takes part in, or occurs as a result of, a chemical reaction All matter can be considered to be chemicals or mixtures of chemicals. chemical reaction: a rearrangement of atoms such that what you end up with products differs from

what you started with reactants methane + oxygen CH4(g) + 2 O2(g) carbon + water dioxide CO2(g) + 2 H2O(g)

sodium + water hydrogen + sodium hydroxide 2 Na(s) + 2 H2O(l) H2(g) + 2 NaOH(aq) Law of Conservation of Mass total mass total mass = of products of reactants Pmass = Rmass synthesis: taking small

molecules and putting them together, usually in many steps, to make something more complex JENNY How many feet is 39.37 inches? equality: 1 ft = 12 in applicable conversion factors: 1 ft ______ 12 in or

( ) 1 ft X ft = 39.37 in ____ 12 in 12 in ______ 1 ft = 3.28 ft Again, the units must cancel. Resources - Intro. to Chemistry Worksheet - vocabulary Worksheet - material safety data sheet (acetone)

Activity - checkbook activity Worksheet - graphing Worksheet - real life chemistry Worksheet - conversion factors Worksheet - scientific notation Worksheet - metric article (questions) Episode 1 - The World of Chemistry Worksheet - significant digits Episode 3 Measurement: The Foundation of Chemistry Worksheet - math review

Episode 4 - Modeling The Unseen Worksheet - math of chemistry Worksheet - article on the metric system Lab introduction to qualitative analysis Textbook - questions Outline (general)