Introduction to Chemistry Mrs. Cramer Michigan Center High School
Believe that life is worth living, and your belief will help create the fact. William James, 1842-1910 American Psychologist and Philospher Whether you believe you can do a thing or believe you can’t, you are right. Henry Ford, 1863-1947 American Car Manufacturer All through my life, the new sights of Nature made me rejoice like a child. Marie Curie, 1867-1934 Polish-Born French Chemist Problems call forth our courage and our wisdom; indeed, they create our courage and our wisdom. it is only because of problems that we grow mentally and spiritually. It is through the pain of confronting and resolving problems that we learn. M. Scott Peck, b. 1936 American Psychiatrist and Writer Don’t be afraid to take a big step if one is indicated. You can’t cross a chasm in two small jumps. David Lloyd George, 1863-1945 British Prime Minister and Statesman
Li 3 H1H1 He 2 C6C6 N7N7 O8O8 F9F9 Ne 10 Na 11 B5B5 Be 4 H1H1 Al 13 Si 14 P 15 S 16 Cl 17 Ar 18 K 19 Ca 20 Sc 21 Ti 22 V 23 Cr 24 Mn 25 Fe 26 Co 27 Ni 28 Cu 29 Zn 30 Ga 31 Ge 32 As 33 Se 34 Br 35 Kr 36 Rb 37 Sr 38 Y 39 Zr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48 In 49 Sn 50 Sb 51 Te 52 I 53 Xe 54 Cs 55 Ba 56 Hf 72 Ta 73 W 74 Re 75 Os 76 Ir 77 Pt 78 Au 79 Hg 80 Tl 81 Pb 82 Bi 83 Po 84 At 85 Rn 86 Fr 87 Ra 88 Rf 104 Db 105 Sg 106 Bh 107 Hs 108 Mt 109 Mg 12 Ce 58 Pr 59 Nd 60 Pm 61 Sm 62 Eu 63 Gd 64 Tb 65 Dy 66 Ho 67 Er 68 Tm 69 Yb 70 Lu 71 Th 90 Pa 91 U 92 Np 93 Pu 94 Am 95 Cm 96 Bk 97 Cf 98 Es 99 Fm 100 Md 101 No 102 Lr 103 La 57 Ac 89 1 2 3 4 5 6 7 * W Cr 24 Am Er 68 S 16 C 77 S 16 S 16 Interactive Periodic Table La 57
Instructor: Mrs. Kathleen Cramer Contact Information: Email - Kathy.email@example.com Kathy.firstname.lastname@example.org Web Site – http://www.mccardinals.org/education/staff/ http://www.mccardinals.org/education/staff/ ( Mrs. Cramer – Science Department) School Phone / voice mail: 764-1440 ext. 3208 Necessary Supplies: Chemistry book – issued by the school, may be kept at home 3-ring binder (1½ - 2") or folder – including filler paper for notes, tab dividers are recommended calculator – a scientific calculator with log (LOG) and exponent (EXP or EE) buttons is recommended pen and/or pencil – no iridescent gel pens, use black or blue ink for labs
Classroom Guidelines: Adherence to the following guidelines will insure a safe and enjoyable year for everyone: Be courteous and respectful to your teacher and classmates. Come to class on-time and prepared to work. Follow ALL safety rules and procedures. Uphold high standards of effort and achievement. Nurtured Heart Check (reset) Warning/Change your behavior Reflection sheet Written reflection/Last warning Check Out Go in the hall until you are ready to refocus/ Automatic After School Detention Check Out to Patrick Removal to ISS Non Negotiables = Referral
Grading: Your semester average is 20% semester exam and 80% marking period grades. Your marking period grade is: Tests/Quizzes60% Activities/Class work/Labs/ Homework40% Final Grade 100% Each marking period, the two lowest Activity grades will be dropped.
Late Work: You should be prepared to turn in all assignments at the BEGINNING of class. Late work turned in within 24 hours will be evaluated and given a grade of 70%. Late work turned in after 24 hours will be evaluated and given a grade of 50%. All work for the marking period will be due for 50% credit by the Wednesday before the end of the marking period. Absences: If you come to school but miss class for any reason, you are expected to turn in all assignments to me or to my box in the MCHS office. If you are absent the day an assignment is due, you are expected to turn it in the next school day. All scheduled tests and quizzes are required to be taken on the assigned date regardless of previous absences during the week.
A cademic D ishonesty P olicy Academic integrity means that all work is done by the students. Any type of dishonesty in school work is not integrity. Dishonesty includes, but is not limited to: 1. Copying the work of another student 2. Using notes during tests and quizzes without permission 3. Copying and pasting from electronic media 4. Providing answers to others When academic dishonesty occurs: a. The student(s) will receive a ‘0’ for the assignment b. A second infraction will result in disciplinary action If a student is using the work of others all students involved will be given a “0”. If the assignment is not a science assignment, the work will be given to the appropriate teacher
Activity Corrections: Activity grades below 80% are eligible for correction. Activity corrections are due two days after the Activity is returned. Corrections should be made in a different color on the front and/or back of the Activity. Math problems should be reworked (all work must be shown). For all other questions, briefly explain why your original answer was wrong. You may regain up to half of the points lost with a maximum score of 80%.
Final Advice: This course is challenging, but you can succeed in this class if you follow these key steps: ØKeep up with your assignments. Falling behind is the kiss of death! ØAsk for help when you need it. Whether that means asking a question during class or coming in for tutoring, I am here to help you in any way I can! ØWork hard and use your brain! I work very hard for you, and I expect nothing less in return.
Homework: Signatures (3) Vocabulary Class Procedures Review (1-10)
Due Today: Signatures (3) Vocabulary Class Procedures Review (1-10) * Please take everything off your desk (place it on the floor or counter)
Analysis: 1.What was the hardest part of this activity? 2.Where you able to get all your cups off the floor or upright on your first attempt? Explain what procedure you used to problem solve the dilemna. 3.What qualities would you look for in a lab partner? 4. Did you and your partners always agree on your course of action (what to do)? If not, what did you do to resolve your issues? If yes, is that always a good thing? Explain.
SAVE FRED A Lesson on Problem Solving and Team Work
Analysis: 1.What was the hardest part of this activity? 2.Where you able to Save Fred on your first attempt? Explain what procedure you used to problem solve the dilemna. 3.What qualities would you look for in a lab pminer? 4. Did you and your pminer always agree on your course of action (what to do)? If not, what did you do to resolve your issues? If yes, is that always a good thing? Explain.
Due Today: Why Should I Study Chemistry? –5 Questions or “I Wonder…” statements
Pre-Assessment What do you know? What will we learn? What will I be assessed on?
Safety: Critical Thinking and Applications In each of the following situations, write ‘yes’ if the proper safety procedures are being followed and ‘no’ if they are not. Then give reasons for your answer. Gina is thirsty. She rinses a beaker with water, refills it with water, and takes a drink. Bram notice that the electrical cord on his hotplate is frayed near the plug. He takes the hotplate to his teacher and asks for permission to use another one. The printed direction in the lab sheet tells a student to pour a small amount of hydrochloric acid into a beaker. Jamal puts on safety goggles before pouring the acid into the baker. It is rather warm in the laboratory. Anna slips off her shoes and walk barefoot to the sink to clean her glassware. While washing glassware, Mike splashes some water on Evan. To get even, Evan splashes him back. During an experiment, Lindsey decides to mix two chemicals that the lab procedure does not say to mix, because she is curious about what will happen.
Basic Safety Rules Use common sense. No unauthorized experiments. No horseplay. Handle chemicals/glassware with respect.
Safety Features of the Lab safety shower fire extinguisher eye wash fume hood circuit breaker switch
Government Regulation The government regulates chemicals to protect the… OSHA worker FDA USDA FAA CPSC consumer EPA environment
Thalidomide Prescription drug for morning sickness in the 1960’s never was proven safe and effective (efficacy) to the Food and Drug Administration in the United States Side-effect from “bad” drug –Stopped development in fetus Short arms; “flipper-babies”
Mercury Poisoning One tiny drop of mercury shatters lives and science LYME, N.H. (AP) — It was just a drop of liquid, That night, Leon drove her to the emergency just a tiny glistening drop. It glided over her glove room. It was Monday, Jan. 20, 1997, five months like a jewel.since she had spilled the drop in the lab. Scientist Karen Wetterhahn knew the risks: The Just a single drop of liquid. Yet somehow it had bad stuff kills if you get too close.penetrated her skin. She took all the precautions working with mer- By the weekend, Karen couldn't walk, her speech cury in her Dartmouth College lab — wearing pro-was slurred and her hands trembled. Leon paced the tective gloves and eye goggles, working under a house. "Virus" seemed an awfully vague diagnosis, ventilated hood that sucks up chemical fumes. for symptoms that were getting worse every day. So on that sunny day in August, when she acci- "It's mercury poisoning," Dr. David Nierenberg dentally spilled a drop, she didn't think anything ofsaid. "We have to start treatment immediately." it. She washed her hands, cleaned her instruments Leon hung up with relief. At last, they understood and went home. the problem. Now maybe they could fix it. It was just a drop of liquid, just a tiny glistening It seemed impossible to believe that anything drop. could be wrong with Karen Wetterhahn, one of At first, friends thought she had caught a stomachthose quietly impressive individuals whose lives bug on her trip to Malaysia. It wasn't until she seemed charmed from the start. started bumping into doors that her husband, Leon Serious and hardworking, she excelled at every - Webb, began to worry. Karen, always so focused, thing she turned to — science or sailing or skiing. always so sure of her next step, was suddenly fallingShe grew up near Lake Champlain in upstate New down as if she were drunk.York in a family so close that when she and her only In 15 years together, she had never been sick, nev-sister became mothers, they named their daughters er stopped working, never complained. Leon wasafter each other: Charlotte and Karen. stunned when she called for a ride home from work. Karen was always the brilliant one of the family, Over lunch a few days later, Karen confided to herthe one who would do great things. And she did, be- best friend, Cathy Johnson, that she hadn't felt rightcoming the first woman chemistry professor at for some time. Words seemed to be getting stuck inDartmouth, running a world-renowned laboratory her throat. Her hands tingled. It felt like her wholeon chromium research, devoting herself to her body was moving in slow motion.work. "Karen," Johnson said as she drove her back to It was important work, the kind that could lead to the college, "we've got to get you to the hospital."cures for cancer and AIDS. Karen thrived on it. She "After work," Karen promised, walking unsteadi-loved nothing more than experimenting with a ly into the Burke chemistry building for the lastchemical, figuring out its bad side and how it breaks time.down living things. Karen Wetterhahn, a chemistry Professor at Dartmouth College, died of mercury poisoning after spilling just one drop in a labor- atory on Aug. 14, 1996. The mercury penetrated her skin through gloves.
Safety Equipment Fire Extinguisher Type A Type B Type C Safety Goggles Safety Shower
Chemical Burns Chemical burns on feet. Skin burned by chemicals Flammable ReactiveHealth Special
SAFETY in the Science Classroom Obey the safety contract –Use common sense –No unauthorized experiments –Wear safety glasses –Safety is an attitude! –Don’t take anything out of lab –Read and follow all instructions
Material Safety Data Sheet (MSDS) Gives information about a chemical. Lists “Dos” and “Don’ts.”
Chemical Exposure a one-time exposure causes damage acute exposurechronic exposure damage occurs after repeated exposure
How Toxic is “Toxic?” Flammable Explosive Radioactive Corrosive Irritant Toxic –Chronic –Chronic toxicity toxicity: low doses repeated over a long period of time –Acute –Acute toxicity toxicity: immediate effect of a substance as a result of a single dose Chemicals may cause harm in many different ways.
Toxicity Which is more toxic? http://lansce.lanl.gov/training/FST2004/images04/chemicals1.gif
the lethal dosage for 50% of animals on which the chemical is tested LD 50 There are various ways an LD 50 can be expressed. For example, acetone has the following LD 50 s: ORL-RAT LD 50 :5,800 mg/kg IHL-RAT LD 50 :50,100 mg/m 3 -h SKN-RBT LD 50 :20 g/kg
Toxicity Which is more toxic? Chemical A: LD 50 = 3.2 g/kg Chemical B: LD 50 = 48 mg/kg Chemical B is more toxic because less of it proves fatal to half of a given population.
Knowledge = Safety Material Safety Data Sheet (MSDS) –Lists hazards, special handling instructions, and risks associated with a material. Supplied by manufacturer. Acute Exposure –Single episode can cause great damage Chronic Exposure –Many episodes over a period of time cause damage Carcinogen – causes cancer Mutagen – causes mutations (genetic defects) Tetragen – causes birth defects Neurotoxin – severely poisonous and toxic
Material Safety Data Sheet Keys Material Safety Data SheetMaterial Safety Data Sheet questionsquestions Material Safety Data SheetMaterial Safety Data Sheet questionsquestions Acetone MSDS http://www.unit5.org/chemistry/intro.html
Science What is the goal of science? Is it the same for everyone? Explain. Journal on scrap paper
The Six Levels of Thought Knowledge Comprehension Application Analysis Synthesis Evaluation “Success is a journey, not a destination.” -Ben Sweetland “Successful students make mistakes, but they don’t quit. They learn from them.” -Ralph Burns “Success consist of a series of little daily efforts.” -Marie McCuillough
Job Skills for the Future Evaluate and Analyze Think Critically Solve Math Problems Organize and Use References Synthesize Ideas Apply Ideas to New Areas Be Creative Make Decisions with Incomplete Information Communicate in Many Modes Chemistry will develop ALL of these skills in YOU!
A Description of a Burning Candle A photograph of a burning candle is shown 1 in the upper right corner. The candle is cylindrical 2 and has a diameter 3 of about 3 cm. The length of the candle was initially about 16 centimeters 4, and it changed slowly 5 during observation, decreasing about 1 cm in one hour 6. The candle is made of a translucent 7, white 8 solid 9 which has a slight odor 10 and no taste 11. It is soft enough to be scratched with the fingernail 12. There is a wick 13 which extends from top to bottom 14 of the candle along its central axis 15 and protrudes about 5 mm above the top of the candle 16. The wick is made of three strands of string braided together 17. A candle is lit by holding a source of flame close to the wick for a few seconds. Thereafter the source of flame can be removed and the flame sustains itself at the wick 18. The burning candle makes no sound 19. While burning, the body of the candle remains cool to the touch 20 except near the top. Within about 1.5 cm of the top the candle is warm 21 (but not hot) and sufficiently soft to mold easily 22. The flame flickers in response to air currents 23 and tends to become quite smoky while flickering 24. In the absence of air currents, the flame is of the form shown in the photograph, though it retains some movement at all times 25. The flame begins about 2 mm above the top of the candle 26, and at its base the flame has a blue tint 27. Immediately around the wick in a region about 2 mm wide and extending about 5 mm above the top of the wick 28 the flame is dark 29. This dark region is roughly conical in shape 30. Around this zone and extending about 1 cm above the dark zone is a region which emits yellow light 31, bright but not blinding 32. The flame has rather sharply defined sides 33 but a ragged top 34. The wick is white where it emerges from the candle 35, but from the base of the flame to the end of the wick 36 it is black, appearing burnt, except for the last 0,5 cm, where it glows red 37. The wick curls over about 3 mm from its end 38. As the candle becomes shorter, the wick shortens too, so as to extend roughly a constant length above the top of the candle 39. Heat is emitted by the flame 40, enough so that it becomes uncomfortable in 10 to 20 seconds if one holds his finger 10 cm to the side of the quiet flame 41 or 10 – 12 cm above the flame 42. O’Connor Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles 1982, page 462,
The Functions of Science pure scienceapplied science the search for knowledge; facts using knowledge in a practical way
Pure Science The search for facts about the natural world. ? - In science, we often try to establish a cause-effect relationship. - Driven by curiosity: the need to know, explore, conquer something new.
Applied Science The practical application of scientific discoveries. -Also known as technology “technology” - Used to improve our lives Cell phones Biodegradable garbage bags
Corning Glass FAILED…but SUCCEEDED at making great cookware that can withstand extremes in temperature. Design a face shield to protect and provide clear vision.
How does scientific knowledge advance? 1. curiosity 2. good observations 3. determination 4. persistence
Aluminum Mining Charles Martin Hall 1850s: aluminum sold for $500 / pound Developed method to extract aluminum from bauxite Hall’s method –1 pound Al costs 30 cents 4-6 pounds bauxite current1 lb Al + =
End Homework: Complete Vocabulary Sheet – Due tomorrow. Make sure you turn in your candle lab before you leave.
Warm Up: The Scientific Method You’ve been taught the scientific method in almost every science class you’ve had since 3 rd grade. Each time it varied just a little. Could you narrow the steps of the scientific method down to just 3 steps??? What would they be?
Warm Up Using a Scientific Approach What is the goal of scientific methods? Why are scientific models useful? Does every scientific method begin with an observation? Explain.
Guiding Questions Scientific explanations must meet certain criteria: they should be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public. Scientific experiments are conducted after much thought about what may be causing the phenomena in order to isolate important factors. In order to isolate these factors careful planning, including addressing safety issues, must be taken into consideration before attempting experiments. In order to draw a valid conclusion from an experiment, all variables except for that which is being tested must be controlled. Measurements communicate not only a magnitude and the system of measurement (unit) but also information about the tool used to make the measurement through precision (significant figures) and uncertainty
Using the scientific method requires that one be a good observer. observationinference involves a judgment or assumption uses the five senses
“My mother the eye doctor” Observation or Inference? One player is holding a bat.The player holding the bat is talking.One of the teams is called the “Reds.” One player is wearing a catcher’s mask. One player is a catcher.Names are written on the uniforms.The players in the picture are on opposite teams.The adult is the umpire.The piece of paper is a note from the mother of the batter.The adult is holding a piece of paper.The mother of the batter is an optometrist or opthalmologist (an eye doctor).
The Skeptical Chemist Robert Boyle In “The Sceptical Chymist” scientific speculation Boyle stated that scientific speculation was worthless unless it was supported experimental evidence by experimental evidence. scientific method This principle led to the development of the scientific method. (1661)
Parts of the Scientific Method Identify an unknown. Make a hypothesishypothesis (a testable prediction). Experiment to testExperiment the hypothesis. Draw a valid conclusion.
A Scientific Experiment procedure the order of events in an experiment; the “recipe” Experiments must be controlled; they must have two set-ups that must differ by only one variable. The conclusion must be based on the data. variable any factor that could influence the result
Data Observations are also called data. There are two types of data. qualitative dataquantitative data descriptions; measurements; no numbersmust have numbers and UNITS
How Handy Are You? Mrs. Cramer Title: Hand Dominance # of boxes checked 1 line = 10 boxes
How did Chemistry Become a Science? http://en.wikipedia.org/wiki/History_of_chemistry
The Beginnings The Greeks believed there were four elements. early practical chemistry: household goods, weapons, soap, wine, basic medicine Fire Water Earth Air ~ ~
Timeline 20001000300 AD American Independence (1776) Issac Newton (1642 - 1727) 400 BC Greeks (Democratus ~450 BC) Discontinuous theory of matter ALCHEMY Greeks (Aristotle ~350 BC)) Continuous theory of matter
Alchemy Allegedly, this substance would turn cheap metals into gold. In Europe, alchemy was the quest for the Philosopher’s Stone (the elixir, the Sorcerer’s Stone).
GOLD SILVERCOPPER IRON.............. SAND Alchemy (~500 – 1300 A.D.) Alchemical symbols for substances… transmutation: changing one substance into another the quest for the Philosopher’s Stone It was supposed to change cheap metals into gold. In ordinary chemistry, we cannot transmute elements.
Contributions of alchemists: Information about elements - the elements mercury, sulfur, and antimony were discovered - properties of some elements Develop lab apparatus / procedures / experimental techniques - alchemists learned how to prepare acids. - developed several alloys - new glassware
Equipment List (with descriptions) Lab Equipment Worksheet Lab Safety and Equipment HW Lab Safety and Equipment QUIZ
What is Chemistry? the study of matter and its changes
C H E M Y S T E R Y C H E M - I S - T R Y C H E M A S T E R Y C H E M I S E R Y C h e m i s t r y
Areas of Chemistry Organic Inorganic Analytical Physical Biochemistry The study of most carbon-containing compounds The study of all substances not classified as organic, mainly those compounds that do not contain carbon The identification of the components and composition of materials The study of the properties, changes, and relationships between energy and matter The study of substances and processes occurring in living things
Careers in Chemistry research (new products) production (quality control) development (scale up manufacturing processes) chemical sales software engineering teaching The skills you will develop by an earnest study of chemistry will help you in any career field. Pharmacist
The Scope of Chemistry The chemical industry has a large effect on our lives. bulk chemical manufacturing –acids, bases, fertilizers –#1 chemical = sulfuric acid (H2SO4) synthetic fibers –nylon, polyester, rayon, spandex petroleum products –gasoline, oil, diesel fuel, heating oil, asphalt Pharmaceuticals –medicines, cancer drugs, VIAGRA –1 in 10,000 new products gets FDA approval ALL fields of endeavor are affected by chemistry.
Starting Yearly Salaries Chemist BS $30,000 MS $50,000 PhD $80,000 Related Occupations: Chemical Engineering, biological scientist, chemical technologist, physicists, medical scientists Physician Resident $48,681 Earning $142,000- $360,000 2013 Average Salaries Teachers at Michigan Center???
All fields of endeavor are affected by chemistry.
Graphs Warm Up 1.Name some ways in which scientists can organize data? 2.What does a given point represent on a line graph? 3.Bar, Pie and Line Graphs are each used for specific reasons. Describe what each graph would be used for or give an example. Keep all warm up on one piece of paper for the week. Turn in Friday.
Graphs Bar Graph –Used to display information collected by counting Pie Graph –Used to show how some fixed quantity is broken down into parts Line Graph –Used to show trends or continuous change
Bar Graph shows how many of something are in each category
Bar Graph Number of Students Chemistry Grades Descriptive title Legend Axis labeled (with units)
Line Graph shows continuous change Stock Price over Time
Elements of a “good” line graph axes labeled, with units use the available space title neat
How to read a graph Interpolate - read between data points What volume would the gas occupy at a temperature of 150 K? Extrapolate - read data beyond data points What volume would the gas occupy at a temperature of 260 K? Which do you have more confidence in? Why? (independent variable) (dependent variable) 7 L ~4 L
1. Preview Before answering any questions about the information in a graph, try to understand the basic elements of the graph: What type of graph is it? (e.g. pictograph, bar graph, line graph, scatter plot, circle graph) What does the title tell you about the information in the graph? Read the labels on each axis. What are the units for the scales? Read the legend (if there is one). 2. Identify (Read the Data) Some questions about data can be answered by stating a fact directly from the graph. To answer these types of questions, use the labels and scale on the horizontal and vertical axes to read or locate specific information on the graph.
3. Interpret The answers to some questions require that you interpret information by identifying relationships and trends within the graph. Compare two or more points on the graph to determine a relationship or trend. 4. Extrapolate Some questions about data in graphs ask you to extend, predict, or infer an answer using your own prior knowledge and experience. To read beyond the data is to draw conclusions from evidence in the graph. Identify your own knowledge and experience related to the question. Consider the evidence in the graph that supports your prediction or conclusion.
Scientific Notation warm up Why do scientists use scientific notation? What system of units do scientists use for measurements? How does the precision of measurements affect the precision of scientific calculations? List the SI units for mass, length, and temperature.
In science, we deal with some very LARGE numbers: 1 mole = 602000000000000000000000 In science, we deal with some very SMALL numbers: Mass of an electron = 0.000000000000000000000000000000091 kg Scientific Notation
Imagine the difficulty of calculating the mass of 1 mole of electrons! 0.000000000000000000000000000000091 kg x 602000000000000000000000 x 602000000000000000000000 ???????????????????????????????????
Scientific Notation: A method of representing very large or very small numbers in the form: M x 10 n M x 10 n M is a number between 1 and 10 n is an integer
2 500 000 000 Step #1: Insert an understood decimal point. Step #2: Decide where the decimal must end up so that one number is to its left up so that one number is to its left Step #3: Count how many places you bounce the decimal point the decimal point 12 3 4 5 6 78 9 Step #4: Re-write in the form M x 10 n
2.5 x 10 9 The exponent is the number of places we moved the decimal.
Review: Scientific notation expresses a number in the form: M x 10 n 1 < M <10 n is an integer
Deciding if n is a negative/positive integer If the original number is greater than 1 n+ If the original number is less than 1 n- Standard to Scientific
Scientific to Standard Deciding which direction to move the decimal If n (+) than the answer must be greater than 1 If n (-) than the answer must be less than 1
Scientific Notation Model Sheet Scientific Notation Practice Homework
Warm Up:Convert Standard Scientific Scientific Standard QuestionAnswerQuestionAnswer 50005000. 253427000 9.810 x 10 2 9.810 x 10 -3 8.201 x 10 6 1.301 x 10 -4
Chem Comm Warm Up Convert Standard to Scientific Notation 74 000 0.000 005 Convert Scientific Notation to Standard 4.7 x 10 5 7 x 10 -5
PERFORMING CALCULATIONS IN SCIENTIFIC NOTATION ADDITION AND SUBTRACTION MULTIPLICATION AND DIVISION
EE or EXP means “times 10 to the…” How to type out 6.02 x 10 23 : 6EE. 0322 6y x. 0322 x 16. 02EE320y x 32 x 16. 020 Don’t do it like this… …or like this… …or like this: How to type out 6.02 x 10 23 : 6EE. 0322 WRONG! TOO MUCH WORK.
Example: 1.2 x 10 5 2.8 x 10 13 But instead is written… = 1. 2EE5 32. 8 1 Type this calculation in like this: This is NOT written…4.3 –9 4.2857143 –09 Calculator gives… 4.2857143 E–09 or… 4.3 x 10 –9 4.3 E –9or
Warm Up 1.) (5 x 10 -3 ) x (3 x 10 4 ) 2.) (3 x 10 -4 ) x (3 x 10 -2 ) 3.) (8 x 10 4 ) ÷ (4 x 10 3 ) 4.) (6 x 10 -3 ) ÷ (2 x 10 -1 ) You will turn in your warm ups for the week after we check today’s warm up Do these on your calculator, not in your head. The point is to get familiar with the exponent key on your calculator
Measurements Numbers science is based on measurements all measurements have: - magnitude - units - uncertainty (sig. figs.)
No Cussing! The following 4-Letter words are forbidden here: Inch Mile Foot Pint Yard Acre And we never swear the BIG F (use o C) Please keep it clean and Metric
SI System The International System of Units Derived Units Commonly Used in Chemistry Area and Volume: Derived Units Prefixes in the SI System Map of the world where red represents countries which do not use the metric system
SI measurement Le Système international d'unitésLe Système international d'unités The only countries that have not officially adopted SI are Liberia (in western Africa) and Myanmar (a.k.a. Burma, in SE Asia), but now these are reportedly using metric regularlyThe only countries that have not officially adopted SI are Liberia (in western Africa) and Myanmar (a.k.a. Burma, in SE Asia), but now these are reportedly using metric regularly Metrication is a process that does not happen all at once, but is rather a process that happens over time.Metrication is a process that does not happen all at once, but is rather a process that happens over time. Among countries with non- metric usage, the U.S. is the only country significantly holding out. The U.S. officially adopted SI in 1866.Among countries with non- metric usage, the U.S. is the only country significantly holding out. The U.S. officially adopted SI in 1866. Information from U.S. Metric Association
https://www.dropbox.com/s/7yi7tuhru37qsi m/measuring_American%20Chopper%20vs %20The%20Metric%20System.mp4https://www.dropbox.com/s/7yi7tuhru37qsi m/measuring_American%20Chopper%20vs %20The%20Metric%20System.mp4 Why should we change?
Why do I need to learn the metric system? https://www.dropbox.com/s/anxbhn532astm 5e/measuring_jerseylicious.mp4https://www.dropbox.com/s/anxbhn532astm 5e/measuring_jerseylicious.mp4
The International System of Units Lengthmeter m Massgram g Timesecond s Amount of substancemole mol QuantityNameSymbol Dorin, Demmin, Gabel, Chemistry The Study of Matter, 3 rd Edition, 1990, page 16
SI-US Conversion Factors RelationshipConversion Factors Length Volume Mass 2.54 cm = 1 in. 1 m = 39.4 in. 946 mL = 1 qt 1 L = 1.06 qt 454 g = 1 lb 1 kg = 2.20 lb 1 in 2.54 cm 39.4 in 1 m 39.4 in. 946 mL 1 qt 946 mL 1.06 qt 1 L 1.06 qt 454 g 1 lb 454 g 2.20 lb 1 kg 2.20 lb 2.54 cm 1 in and
Christopherson Scales Made in Normal, Illinois USA Units for Measuring Mass 1 kg = 2.20 lb 1 kg (1000 g) 1 lb 0.20 lb
Comparison of English and SI Units 1 inch 2.54 cm 1 inch = 2.54 cm Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 119
APPROXIMATE CONVERSIONS BETWEEN METRIC & US LENGTH UNITS A meter is about the same length as a yard A meter is about three feet long An inch is about 25 millimeters A foot contains about 30 centimeters
Prefixes in the SI System Power of 10 for Prefix SymbolMeaning Scientific Notation _______________________________________________________________________ mega-M 1,000,00010 6 kilo-k 1,00010 3 deci-d 0.110 -1 centi-c 0.0110 -2 milli-m 0.00110 -3 micro-m 0.00000110 -6 nano-n 0.00000000110 -9 The Commonly Used Prefixes in the SI System Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 118
THE METRIC CONVERSION CHEAT SHEET g (gram) L= (liter) m (meter) Kilo (k) 1000 Hecto (h) 100 Deka (D) (da) 10 Deci (d) 0.1 Centi (c) 0.01 Milli (m) 0.001 LeftRight Base unit prefix smallerlarger
TRY THIS USING THE CHEAT SHEET 1000 mg = ______ g Step 1: Cover the prefixes you are given with one thumb. Step 2: Cover the prefix you need with your other thumb. Step 3: Count the number of dots in between your two thumbs. Step 4: Move your decimal that many places in the direction of given to need.
THE METRIC CONVERSION CHEAT SHEET Kilo 1000 units Hecto 100 units Deka 10 units Basic Unit Deci 0.1 units Centi 0.01 units Milli 0.001 units To convert to a smaller unit, move decimal point to the right the number to dots in between the two prefixes To convert to a larger unit, move decimal point to the left the number to dots in between the two prefixes 123 Move decimal point to the left
TRY THIS USING THE CHEAT SHEET 1000 mg = ____ g Move decimal point to the left
TRY THIS USING THE CHEAT SHEET.15 L = _______ ml
Precision The degree to which repeated measurements under unchanged conditions show the same results. Significant Figure (Also known as significant digits, and often shortened to sig figs) Those digits that carry meaning contributing to its precision. Save vocabulary till we cover sig figs. This is not homework (yet)
Precision The degree to which repeated measurements under unchanged conditions show the same results. Accuracy The degree to which repeated measurements under unchanged conditions show the correct (accepted) results. Chem Comm
Types of errors Systematic Instrument not ‘zeroed’ properly Reagents made at wrong concentration Random Temperature in room varies ‘wildly’ Person running test is not properly trained Errors in a single direction (high or low) Can be corrected by proper calibration or running controls Errors in any direction. Can’t be corrected. Can only be accounted for by using statistics.
Accuracy vs. Precision Random errors: reduce precision Good accuracy Good precision Poor accuracy Good precision Poor accuracy Poor precision Systematic errors: reduce accuracy (person)(instrument)
Precision Accuracy reproducibility check by repeating measurements poor precision results from poor technique correctness check by using a different method poor accuracy results from procedural or equipment flaws.
In terms of measurement Three students measure the room to be 10.2 m, 10.3 m and 10.4 m across. Were they precise? Were they accurate? How would you define them?
A chemist is asked to determine the concentration of a chemical dissolved in a solution. The chemist performs the experiment three times for good measure, and the concentration determined to be 1.74 M, (moles/liter), 1.73 M and 1.75 M. The average of these numbers is 1.74 M. But suppose the chemist is not a very good chemist and made the same mistake in all three experiments: the true concentration of the chemical in solution is 2.32 M. Was this experiment accurate and/or precise? Explain.
Percent Error Indicates accuracy of a measurement your value accepted value Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Percent Error = 1. Mrs. Cramer guessed she would get 5 hours of sleep, but she actually got 8. What was the percent error in her guess? Warm up
Uncertainty in Measurement A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty.
Practice Measuring cm 0 12345 0 12345 0 12345 Warm up
Significant figures (sig figs) How many numbers mean anything. When we measure something, we can (and do) always estimate between the smallest marks. 21345
The better marks the better we can estimate. Scientist always understand that the last number measured is actually an estimate. 21345 Significant figures (sig figs)
The measurements we write down tell us about the ruler we measure with The last digit is between the lines What is the smallest mark on the ruler that measures 142.13 cm? 141 142
Significant figures (sig figs) What is the smallest mark on the ruler that measures 142 cm? 10020015025050
140 cm? l Here there’s a problem is the zero significant or not? 10020015025050 100200
140 cm ? They needed a set of rules to decide which zeroes count. l All other numbers do count. 10020015025050 100200
Significant Figures The numbers reported in a measurement are limited by the measuring tool The numbers reported in a measurement are limited by the measuring tool Significant figures in a measurement include the known digits plus one estimated digit Significant figures in a measurement include the known digits plus one estimated digit
Counting Significant Figures RULE 1. All non-zero digits in a measured number are significant. Only a zero could indicate that rounding occurred. Number of Significant Figures 38.15 cm4 5.6 ft2 65.6 lb___ 122.55 m 122.55 m___
Sandwiched Zeros RULE 2. Zeros between nonzero numbers are significant. (They can not be rounded unless they are on an end of a number.) Number of Significant Figures 50.8 mm3 2001 min4 0.702 lb____ 0.00405 m 0.00405 m ____
Leading Zeros RULE 3. Leading zeros in decimal numbers are NOT significant. Number of Significant Figures 0.008 mm1 0.0156 oz3 0.0042 lb____ 0.000262 mL 0.000262 mL ____
Trailing Zeros RULE 4. Trailing zeros in numbers without decimals are NOT significant. They are only serving as place holders. Number of Significant Figures 25,000 in. 2 25,000 in. 2 200. yr3 200. yr3 48,600 gal____ 48,600 gal____ 25,005,000 g ____
Learning Check A. Which answers contain 3 significant figures? 1) 0.4760 2) 0.00476 3) 4760 B. All the zeros are significant in 1) 0.00307 2) 25.300 3) 2.050 x 10 3 C. 534,675 rounded to 3 significant figures is 1) 535 2) 535,000 3) 5.35 x 10 5 1) 535 2) 535,000 3) 5.35 x 10 5
Learning Check In which set(s) do both numbers contain the same number of significant figures? 1) 22.0 and 22.00 1) 22.0 and 22.00 2) 400.0 and 40 3) 0.000015 and 150,000
Chem Comm Warm Up Convert the following numbers into scientific notation: 1,000,000 _______________________________ 0.00671 _______________________________ 4.50 _______________________________ Convert the following numbers into standard notation: 2.30 x 104 _______________________________ 1.76 x 10-3 _______________________________ 1.901 x 10-7 _______________________________
State the number of significant figures in each of the following: A. 0.030 m 1 2 3 B. 4.050 L 2 3 4 C. 0.0008 g 1 2 4 D. 3.00 m 1 2 3 E. 2,080,000 bees 3 5 7 Warm Up
Significant Numbers in Calculations A calculated answer cannot be more precise than the measuring tool.A calculated answer cannot be more precise than the measuring tool. A calculated answer must match the least precise measurement.A calculated answer must match the least precise measurement. Significant figures are needed for final answers fromSignificant figures are needed for final answers from 1) adding or subtracting 2) multiplying or dividing
Adding and Subtracting The answer has the same number of decimal places as the measurement with the fewest decimal places. 25.2 one decimal place + 1.34 two decimal places 26.54 26.54 answer 26.5 one decimal place
Multiplying and Dividing Round (or add zeros) to the calculated answer until you have the same number of significant figures as the measurement with the fewest significant figures.
Multiplication and Division For these problems, your answer will have the same number of significant digits as the value with the fewest number of significant digits. 608.3 x 3.45 b) 4.8 / 392 a) 3.45 has 3 sig. digits, so the answer will as well 608.3 x 3.45 = 2098.635 = 2.10 x 10 3 b) 4.8 has 2 sig. digits, so the answer will as well 4.8 / 392 = 0.012245 = 0.012 or 1.2 x 10 – 2
i 7.255 x 81.334 = ii 1.142 / 0.002 = iii 31.22 + 9.8 = 22.9 + 7.0 29.9 = iv Warm Up Difficult