Honors Chemistry Introduction to Chemistry

Honors Chemistry Introduction to Chemistry
Chemistry is the study of matter and the transformations it can undergo… Image courtesy: Introduction to Chemistry 1. What is chemistry? 2. What are the four parts of the scientific method? 3. What is a control experiment? 4. Describe the three types of variables. 5. Compare laws, theories, and hypotheses. 6. What is the only way to prove a hypothesis true? 7. Why do laws and theories evolve? 8. What is the last step of solving any problem? 9. What is measurement? 10. What is a dimension? 11. What is a unit? 12. What is the difference between fundamental and derived units? 13. Why is the standard for mass, in the SI, unique? 14. What is the difference between mass and moles? 15. Is density a fundamental or derived unit? 16. How is a conversion factor made? 17. How is one unit converted to another? 18. What is precision? 19. What do the significant figures of a measurement indicate? 20. In what situation are trailing zeros always significant. 21. Numbers in scientific notation have the basic form A x10B. What is the range of A? 22. What kind of number will have a negative B? 23. Why do scientists use graphs? 24. What variables go on which of the axes of a graph? 25. How do direct and inverse relationships differ? 26. Describe the graph of a direct linear relationship. 27. Describe the graph of an inverse parabolic relationship. 28. What is the slope of a horizontal line? 29. In an experiment the independent variable does not change. What is the slope of the graph? 30. During a lab experiment the temperature of the gas in a balloon is varied and the volume is measured. Which of the two variables will be graphed on the horizontal axis and which will be graphed on the vertical axis? 31. What kind of relationship exists between P and z in this equation? P = mv/z2

…Matter is anything that occupies space. Image courtesy - OBJECTIVES: Know the difference between science and technology. Define what chemistry is and what chemists do. Understand why chemistry is important. Explain what matter is and what the different categories of matter are. Diagram how different categories of matter are related. Explain how pure substances differ from mixtures and give examples of each. Classify mixtures as either homogeneous or heterogeneous and explain why. Explain the difference between elements and compounds. Describe what information is contained in the chemical formula of a compound. Discuss the difference between physical changes and chemical changes and classify any changes as either chemical or physical. Explain what is meant by state of matter and indicate the three most common states of matter. List the terms associated with the changes in states of matter and identify the states associated with each term. Explain what happens during a chemical reaction and identify the reactants and products in any chemical reaction. Discuss what is meant by the scientific method and describe the steps involved. Explain the relationship between a theory, law, and experimental data in the use of the scientific method. Define bias and explain its potential impact on the development of scientific theories.

The Six Levels of Thought
Honors Chemistry Introduction to Chemistry Evaluation The Six Levels of Thought Synthesis Analysis “Success is a journey, not a destination.” -Ben Sweetland Application “Successful students make mistakes, but they don’t quit. They learn from them.” -Ralph Burns Our goal is to be able to do synthesis and evaluation of data. We need to begin with simple fact and knowledge recall and build our way up the cognitive ladder. This requires dedication, memorization, problem-solving and hard work. You will fail at times and must not give up - continue learning and questioning your entire life. Do you think there are "good chemicals" and "bad chemicals"? If so, how do they differ? Chemicals are not "good" or "evil". How we use them determines that. e.g. water to a man that is dehydrating in a desert is good while holding someone under water for too long is evil (drowning them). Comprehension “Success consist of a series of little daily efforts.” -Marie McCuillough Knowledge

Honors Chemistry Introduction to Chemistry Use common sense.
Basic Safety Rules Use common sense. No unauthorized experiments. Go over Safety Contract with students. Link for copy of safety contract: No horseplay. Handle chemicals/glassware with respect.

Safety Features of the Lab
Honors Chemistry Introduction to Chemistry Safety Features of the Lab safety shower fire blanket fire extinguisher eye wash fume hood circuit breaker switch

Government Regulation
Honors Chemistry Introduction to Chemistry Government Regulation The government regulates chemicals to protect the… worker OSHA FDA USDA FAA CPSC environment EPA consumer

Chemical Exposure acute exposure chronic exposure a one-time exposure causes damage damage occurs after repeated exposure Examples: A person snorts cocaine a single time and has a heart attack – this is an example of acute exposure. A person is bitten by a venomous snake and dies – this is an example of acute exposure. A person is exposed to a high level of radiation and dies a short time later – this is an example of acute exposure. A person smokes a pack of cigarettes each day for 20 years and develops lung cancer – this is an example of chromic exposure. A person works at a toll booth collecting toll money while inhaling car exhaust fumes – later in life they develop respiratory problems – this is an example of chronic exposure.

Toxicity Which is more toxic? Chemical A: LD50 = 3.2 mg/kg Chemical B: LD50 = 48 mg/kg Students must be sure to have the UNITS of the substances THE SAME when comparing the numbers. For instant: 3.2 g (Chemical C) vs. 48 mg (Chemical D). Because 1000 mg = 1 g mg = g To make a comparison for toxicity you need to compare 3.2 g vs g. Substance D is more toxic – it is the smaller number. Chemical A is more toxic because less of it proves fatal to half of a given population.

The Functions of Science
Honors Chemistry Introduction to Chemistry The Functions of Science pure science applied 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. Pure science is often what is done at universities and colleges. The basic understanding of why and how things work and react as they do are discovered. The goal in pure science is NOT to make money – but to understand. Industry often funds research at universities in hopes of taking what is learned to make a marketable product and to make money. This synergistic relationship between the business community and academia is beneficial to both parties. Driven by curiosity: the need to know, explore, conquer something new.

Fundamental Properties of Models
Honors Chemistry Introduction to Chemistry Fundamental Properties of Models A model does not equal reality. Models are oversimplifications, and are therefore often wrong. Models become more complicated as they age. We must understand the underlying assumptions in a model so that we don’t misuse it.

Using the scientific method requires that one be a good observer. observation inference uses the five senses involves a judgment or assumption

Data Observations are also called data. There are two types of data. Scientists prefer quantitative data over qualitative data. It is easier to replicate and compare quantitative data. qualitative data quantitative data descriptions; measurements; no numbers must have numbers and UNITS

Parts of the Scientific Method
Honors Chemistry Introduction to Chemistry Parts of the Scientific Method Identify an unknown. Make a hypothesis (a testable prediction). Experiment to test the hypothesis. Draw a valid conclusion.

Hypotheses A tentative explanation for the observations May not be correct, but it puts the scientist’s understanding of the system being studied into a form that can be tested Copyright © Pearson Benjamin Cummings. All rights reserved.

Experiments Tests the validity of the hypothesis Are systematic observations or measurements made under controlled conditions, in which the variable of interest is clearly distinguished from any others If experimental results are reproducible, they are summarized in a law. Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

A Scientific Experiment
Honors Chemistry Introduction to Chemistry A Scientific Experiment procedure the order of events in an experiment; the “recipe” variable any factor that could influence the result 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.

Scientific Method Observations Hypothesis Experimentation Controlled (one variable changed at a time) Collect data (quantitative and qualitative) Analyze data (graph, statistics…trends) Form valid conclusion. After many experiments…form a theory. Recall, our checkbook activity. Each check represented data. As more data was collected it became clearer what had happened. Some bits of data were unimportant. Most likely, you had to modify your theory as new pieces of data were revealed.

Fundamental Properties of Models
Honors Chemistry Introduction to Chemistry Fundamental Properties of Models A model does not equal reality. Models are oversimplifications, and are therefore often wrong. Models become more complicated as they age. We must understand the underlying assumptions in a model so that we don’t misuse it.

Scientific Law vs. Scientific Theory
Honors Chemistry Introduction to Chemistry Scientific Law vs. Scientific Theory A law states what happens. Law of Gravity A theory tries to explain why or how something happens. You can distinguish between a theory and a law by asking the question: Is the proposal measurable? Yes, the statement is a law. No, it is a theory. Theory of Gravity Atomic Theory Collision Theory of Reactions

Experiments Law – A verbal or mathematical description of a phenomenon that allows for general predictions – Describes what happens and not why – Unlikely to change greatly over time unless a major experimental error is discovered Theory – Attempts to explain why nature behaves as it does – Is incomplete and imperfect, evolving with time to explain new facts as they are discovered Copyright 2007 Pearson Benjamin Cummings. All rights reserved.

Make observation Scientific Method Ask question Develop hypothesis Test hypothesis with an experiment Test hypothesis with further experiments Revise hypothesis Analyze data and draw conclusions Hypothesis IS supported Hypothesis is NOT supported Develop theory Wysession, Frank, Yancopoulos, Physical Science Concepts in Action, 2004, page 8

Question First What does the scientist want to learn more about? Then Research Gathering of information Scientific Method An Overview Next Hypothesis An “Educated” guess of an answer to the question Then Procedure/ Method Written and carefully followed step-by-step experiment designed to test the hypothesis Next Data Information collected during the experiment And And Observations Written description of what was noticed during the experiment Finally Conclusion Was the hypothesis correct or incorrect?

Phlogiston Theory Phlogiston theory of burning (a) When an object burns it gives off a substance called phlogiston. (b) When the space surrounding the burning object is filled with phlogiston, the object will no longer be able to burn. (a) (b) phlogiston phlogiston Phlogiston can not be tasted, smelled, weighed…but it does exist. Like FAITH (you believe it) but can’t measure it quantitatively. PHLOGISTON THEORY “The German chemist Georg Ernst Stahl ( ) believed that when substances burned they gave up a substance he called phlogiston. This theory proved helpful in explaining reactions, and it diverted many thinkers, but it was proved wrong by Antoine Lavoisier. THE FATHER OF CHEMISTRY After Englishman Joseph Priestly discovered oxygen in 1774, Frenchman Antoine Lavoisier ( ), who gave the gas the name oxygen, started examining its properties and those of air. He proposed a totally new theory which explained both the formation of metal oxides and allowed for the reactions which occur when burning wood or candles. Lavoisier came from a wealthy family. Because of his involvement with tax collection, he was tried and guillotined during the French Revolution.” Eyewitness Science “Chemistry” , Dr. Ann Newmark, DK Publishing, Inc., 1993, pg 30 Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 4

Combustion Theory Modern theory of burning (c) When an object burns, it uses up a substance (oxygen) in the surrounding space. When the space surrounding the burning object has too little oxygen in it, the object will no longer be able to burn. Antoine Lavoiser (c) (d) oxygen ANALYZING OXYGEN Lavoisier set out to analyze what made up atmospheric air. He heated mercury in a retort, the neck of which led to an upturned bell jar containing air, over mercury in a large container known as a pneumatic trough. He knew that the total volume of air in the retort and bell jar at the start. As the mercury was heated, he saw red scales of “calx” (mercury oxide) appear on the surface of the mercury of the mercury. Twelve days later, when he was sure no further reaction was occurring, he measured the remaining air in the bell jar and found about five-sixths of the volume left. Nothing could burn in the remaining air, nor could anything breathe in it. When he heated the calx of mercury, he obtained the same amount of gas (oxygen) as he had lost in the first experiment.” Eyewitness Science “Chemistry” , Dr. Ann Newmark, DK Publishing, Inc., 1993, pg 31 Antoine Laurent Lavoisier ( ) executed May 8, 1794 during the French Revolution. His wife’s father was a tax collector and he received money. Anyone that was associated with the aristocracy or tax collection were executed by the guillotine. Paris News: 8 May Chemical Revolutionary Executed! Phlogiston Debunker Beheaded Twenty eight members of the Fermés Generalé swept up in raids by government security forces in recent months, were this day tried, convicted and executed. The accused were convicted on two counts of "plotting against the government by watering the soldiers' tobacco and appropriating revenue that belonged to the state." (2) Early this afternoon, the life on one Antoine Laurent Lavoisier came to a sudden end with the swift fall of the guillotine. M. Lavoisier left this world immediately preceeded by his father-in-law, Jacques Paulze. A famous chemist, Lavoisier had friends who tried unsuccessfully to intervene with the courts on his behalf. The courts replied, "The Republic has no use for savants." (1) It was said of M. Lavoisier that he was serene to the end, accepting the judgment of the courts. What brought this giant of the chemical revolution to this tragic end? Perhaps the roots of his fall can be found in an exclusive interview, granted by Marie-Anne Pirette Paulze (Madame Lavoisier) several months before his death, to our Woodrow Wilson Institute News (WWIN) correspondent. WWIN: "Libérté, Fraterneté et Equalité - Liberty, Brotherhood and Equality". These are the words being chanted by the Citizen mobs. They roam the streets, searching out the remaining supporters of the recently-deposed regime of Louis XVI and Marie Antoinette. Nowhere does their "justice" appear more unjust than in the arrest of Antoine Laurent Lavoisier from his home on 24 December, In this time of chaos and confusion, Madame Lavoisier (Marie-Anne Pirette Paulze) appeared calm. WWIN: How good of you to see me, Mme. Lavoisier. When I visited your husband's laboratory the other day I saw that you were engaged in an experiment. Would you tell me about it? Mme. L: Yes! Yes! Antoine and I were in the laboratory along with M. Seguin. We looked quite silly, really. Our associate, M. Sequin agreed to have his body wrapped completely in a varnished silk bag. The sweat from his body was kept inside the bag. It was even sealed to his lips with turpentine and pitch! He was breathing through a tube into Antoine's collecting flasks. This was Antoine's most recent experiment on the respiration of air in living organisms. I was writing down Antoine's observations and sketching the experiment. That was when they charged in to arrest my husband. WWIN: There is much unrest in Paris these days. Your husband's troubles apparently arose from his duties as fermiér (tax collector) from Would you care to comment on the charges of Citizen Marat. Mme. L.: The charges are completely false. Watering the soldier's tobacco, indeed! Antoine developed a technique of moistening the leaves so that the tobacco would not be dry and brittle! It was no crime for my husband to invest his mother's inheritance in the Fermés Generalé. The fermiérs paid a fixed sum of money every year to the King. It was then their responsibility to collect the taxes for their region - taxes on the tobacco, the salt, the materials that come and go from each city etc. etc. He merely wanted a reliable source of income so that he would have the time and money to finance his laboratory and his work for the Academy of Science. These past few years have been troubled times for all of France, as you well know. Antoine has been almost the sole support of the work at the Academy of Sciences. He spares no expense for his laboratory. Antoine has been a man devoted to the people of France. It was he who helped abolish the detestable tax piéd forchu against the Jews. He would not be satisfied at schools only for the rich so he established free schools for the peasant people of his tax district. He advocated the use of fire hydrants, so as to protect the city in times of fires. He was the one who supervised the moving of the low-grade gunpowder OUT OF the Artillery and brought the better quality gunpowder IN. These silly Citizen mobs listen to any story they hear. Their leaders were suspicious and argued that Antoine was trying to disarm the Artillery! Such nonsense. But these are troubled times. Is is true that elsewhere they are calling this "The Reign of Terror"? How true those words are. His fermiér associations of the past are a perfect excuse for Citizen Marat. That scoundrel! WWIN: So you think that his arrest was politically motivated? Mme. L.: But, of course, Antoine has many enemies. That journalist Marat‹you know he had ambitions for scientific achievement. He wrote a paper in which he claimed to have observed the element "fire"! My husband was unimpressed. Just as Antoine exposed his poor chemistry to the Academy of Science, I shall expose this charlatan "Friend of the People". There are even those in the French Academy of Science who have visited our home, eaten many fine meals, spent many hours conversing with all manner of learned men from all of Europe. They too have their jealousies toward Antoine. His work in the Fermés Generalé supported all of their science in recent years, but this they forget. Instead they prefer to say that he was an ambitious man. He entered the Academy when he was but 23. They say it was his father and aunt who pulled their aristocratic strings for his admission. They forget his gold medal from the King for his street lamp design (1766). They forget his work with Guettard mapping the geology and mineralogy of France ( ). They forget his continual need for pli cachété sealing his scientific observations in envelopes, lest others steal his works. Instead, they say he stole others' ideas. It was he alone who developed the theories to explain the works of others. Antoine expanded the experimental work of others. Using the balance, fitting bits and pieces of observations together, explaining their significance, arranging it all into one grand picture - that is what Antoine did best. These men who accuse him, these petty little men who desire only to have their names made a small reference to in the works of the great Antoine Lavoisier! WWIN: If you would please, Madame Lavoisier, tell us something about the personal life you have shared with your husband? Mme. L.: (pause) My Antoine is a man of great devotion. Antoine has been a devoted husband to me, just as I have been a devoted wife to him. We have a very happy marriage. Yes, it has been happy, (pause) even without children. I did so much of my own growing up with Antoine. He was 28 and I, not yet 14, when we married in In 1768, after he had been elected to the French Academy of Sciences, Antoine met my father in the Fermés Generalé, what you in your country call the Internal Revenue Service. My father held the controlling shares of the Fermés, so naturally Antoine would need to discuss business with him. That is how we met. This tall gentle-mannered man with grey eyes grew fond of my blue eyes and brunette hair! I set out from the start to make myself useful to Antoine. He agreed and I studied with David, the talented artist who painted a portrait of us. I take down the observations and make the illustrations in his laboratory notebooks. I am comfortable in English and Latin and have even studied what science Antoine would teach me as he does his work. This talent I have used to translate the works of other scientists so that Antoine can assess their work. He is a man devoted to his work. Before his arrest, every day he would work in his beloved laboratory; from 6 to 9 in the morning and again from 7 until 10 at night. One day a week was his jour de bonheur, day only for science. It was for him, a day of happiness; ...It was there that you should have seen and heard this man with his precise mind, his clear intelligence, his high genius, the loftiness of his philosophical principles illuminating his conversation. (5) Even now, in the Bastille, that place of infamy, he writes his Collected Works. Antoine is known to edit, rewrite and even rethink his earlier conclusions about his experiments. He never grows weary of his science. To save time for his experiments, he once put himself on a bread and milk diet! He is a man devoted to great ideas and great words. He himself could foresee the importance and greatness of his own work. This is what Antoine said: This theory (burning) is not, as I hear it called, the theory of the French chemists. It is mine. It is a right that I claim by the judgment of my contemporaries and at the bar of history. (5) And: All young chemists adopt the theory and from that I conclude that the revolution in chemistry has come to pass. (5) WWIN: Please tell us about some of his experiments. Mme. L.: His early work was much concerned about matters related to geology. Antoine concluded that the various layers of terre nouvelle are evidence of a cyclic advancement and retreat of the sea. This theory about the stratification of the earth (1776) introduced new ideas into the study of geologic time. Since 1766 he has collected data for himself, and begged others to do likewise on their journeys. He is especially interested in data about the pressure and temperature of the air. He plans someday to compose this data into a theory about the changes that alter the surface of the earth. He says that he prefers to call himself a phyiscien, a man of physics, though he is an adjoint chimiste at the Academy of Sciences. Antoine did his first "chemical" investigation on the rock gypsum (1764). He has made many careful measurements about its properties and interactions. This was one of the works that brought him to the attention of the French Academy of Sciences. Antoine is most curious also, about the substance "water". Previously it was thought to be one of only four "elements". In 1770 he demonstrated that "water" cannot be changed into "earth". With just his balance, some water, and a boiling apparatus that did not allow the emanations from the boiling water to escape, Antoine proved that materials leech out of the porous glass. This is what they previously called water turning into earth! With Pierre Laplace from he showed that water could be formed when hydrogen and oxygen gases were burned together. But those more modern names came later. Antoine's revolutionary work, yes, revolutionary work, has changed even the words that are used to discuss Chemistry. Then he was still using the alchemist's phrases "inflammable air" and "fixed air". Such silliness! Can you imagine? The stubborness of some people to continue using such terms when Antoine has already explained it all in his magnum opus of 1789‹"Traite Elementaire de Chimie". Antoine has published this new nomenclature that lists 55 "elements". Of course, he has kept some of the old "elements". Not phlogiston to be sure, but those "elements" that men of reason would still agree upon. Let me quote him for you: We must clean house thoroughly, for they have made use of an enigmatic language peculiar to themselves, which in general presents one meaning for the adept and another for the vulgar, and at the same time contains nothing that is rationally intelligible either for one or for the other." (1) It was my Antoine who wrote in 1772 (but did not publish) that a single substance could exist as solid, liquid and gas. The very same substance! The only way they differ, is the amount of the element "fire" that they contain! Such an idea was not conceived of before! Oh, yes. M. Priestley of England was the first to isolate his dephlogisticated air (1773). M. Priestley wrote and published not one, but three volumes:"Experiments and Observations on Different Kinds of Air". I myself translated Priestley's works for Antoine. I know what was in his original papers and I know what was in Antoine's work. M. Priestley called this emanation from red calx of mercury (mercuric oxide) dephlogisticated air. Dephlogisticated air, indeed! It was Antoine's keen insight and refined measurements that have laid this Phlogiston nonsense to rest for men of reason (1786). If Antoine did not make reference to M. Priestley in his writings, it is only because Antoine's works went so much beyond this nonsense of phlogiston flowing out of a substance, thereby causing that substance to burn. Most recently Antoine has been working to establish a precise unit for metric mass, length and time. Using his most precise balances, he weighs only a given volume of only the most purely distilled water. Oh yes, my Antoine is no little figure to deal with. He has contributed much to Science and much to his country. WWIN: Thank-you Mme. Lavoisier for talking with us at such an unsettling time in your life. Mme. L.: I thank-you for taking such time and care to worry about Antoine Lavoisier. WWIN: It is perhaps fitting to end this story with a quote from M. LaGrange, a mathematician and friend of the Lavoisier family: It took but a moment to cut off that head, though a hundred years perhaps will be required to produce another like it.(1) Suggested Reading List The suggested reading list is based upon the opinions of the authors of this report. It is intended only as a guide for the general reader. Bernard Jaffe, The Story of Chemistry From Ancient Alchemy to Nuclear Fission,4th ed., Dover Publications, Inc., New York, New York, 1976, pp Excellent anecdotes from Lavoisier's life. Henry Guerlac, Antoine-Laurent Lavoisier: Chemist and Revolutionary, Scribner, New York, NY, pages. --Short book that is easy to read and interesting. It was written by the man most people considered to be the expert on Lavoisier. Douglas McKie, Antoine Lavoisier: Scientist, Economist, Social Reformer, Henry Schuman, New York, NY, 428 pages. --This is an interesting , somewhat longer treatment of Lavoisier with an excellent bibliography at the end. Again it is easy reading. Aaron J. Ihde, The Development of Modern Chemistry, Dover Publications, New York, NY,1984, pp This is a segment of a much longer history of Chemistry that has information similar to work by Jaffe and Partington. J.R.Partington, A Short History of Chemistry, Dover Publications Inc., New York, NY, 1989, pp This is a fact filled segment in a book full of facts about historically significant figures from the Chemistry world. It is somewhat dry reading but useful nonetheless. Antoine Lavoisier, Elements of Chemistry, Dover Publications Inc., New York, NY,1965, 511 pages. --If you would like to get a good flavor of Lavoisier and his chemistry this is the book to read. It is his revolutionary work of 1789 that helped to change chemistry forever. Bibliography 1. Henry Guerlac, Antoine-Laurent Lavoisier: Chemist and Revolutionary, Scribner, New York, NY, pages 2. Aaron J. Ihde, The Development of Modern Chemistry, Dover Publications , New York, NY, 1984, pp 3. Bernard Jaffe, The Story of Chemistry From Ancient Alchemy to Nuclear Fission, 4th ed., Dover Publications, Inc., New York, New York, 1976, pp 4. Antoine Lavoisier, Elements of Chemistry, Dover Publications Inc., New York, NY,1965, 511 pages. 5. Douglas McKie, Antoine Lavoisier: Scientist, Economist, Social Reformer, Henry Schuman, New York, NY, 428 pages. 6. J.R.Partington, A Short History of Chemistry, Dover Publications Inc., New York, NY, 1989, pp Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 4

Phlogiston Theory of Burning
Honors Chemistry Introduction to Chemistry 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.

Laboratory Equipment Laboratory equipment should never be removed from the labs. The equipment should never be used in a manner not described by your teacher. Unauthorized lab experiments are strictly forbidden. You may not use the lab without a teacher present and with your teachers permission.

Zinc Pennies Before 1982, all pennies were solid copper (except 1943). Copper was used to make bullet shells in WW II. By 1943, the supply of copper metal was in short supply. The US government did not want to ‘waste’ copper on making pennies. Pennies were made with steel metal. They looked silver. A shortage of copper drove the price of copper up in the early 1980s. If melted down, the copper could be sold for more than one cent. What's So Special About the 1943 Copper Penny? According to the American Numismatic Association, the 1943 copper-alloy cent is one of the most idealized and potentially one of the most sought-after items in American numismatics. Nearly all circulating pennies at that time were struck in zinc-coated steel because copper and nickel were needed for the Allied war effort. Forty 1943 copper-alloy cents are known to remain in existence. Coin experts speculate that they were struck by accident when copper-alloy 1-cent blanks remained in the press hopper when production began on the new steel pennies. A 1943 copper cent was first offered for sale in 1958, bringing more than $40,000. A subsequent piece sold for $10,000 at an ANA convention in 1981. The highest amount paid for a 1943 copper cent was $82,500 in 1996. Because of its collector value, the 1943 copper cent has been counterfeited by coating steel cents with copper or by altering the dates of 1945, 1948, and 1949 pennies. The easiest way to determine if a 1943 cent is made of steel, and not copper, is to use a magnet. If it sticks to the magnet, it is not copper. If it does not stick, the coin might be of copper and should be authenticated by an expert. After 1982, pennies were made from zinc. A thin coating of copper was pressed on the zinc.

Honors Chemistry Introduction to Chemistry transmutation
changing one substance into another COPPER GOLD  Philosopher’s Stone The identity of an element is determined by the number of protons in the nucleus of the atom. To change one element into another element requires changing the nucleus of the atom. Changing the nucleus of an atom can occur in nuclear reactions (e.g. nuclear power plants, atomic bombs) but not during chemical reactions. In chemical reactions atoms are rearranged into new combination. Atoms do not change from one element to another - only new combinations of atoms are formed. In ordinary chemical reactions, we cannot transmute elements into different elements.

Areas of Chemistry organic physical the study of carbon- containing compounds measuring physical properties of substances e.g., the melting point of gold inorganic everything except carbon e.g., compounds containing metals biochemistry the chemistry of living things

Government Regulation of Chemicals …to protect the… environment consumer worker Consumer Product Safety Commission, USDA, BATF, FDA OSHA EPA

Measurements Numbers science is based on measurements all measurements have: - magnitude - uncertainty - units mathematics is based on numbers exact numbers are obtained by: - counting - definition

Graphs Line Graph Used to show trends or continuous change Bar Graph Used to display information collected by counting Pie Graph Used to show how some fixed quantity is broken down into parts GRAPHS Each graph is used for a specific reason.

Convert 41.2 cm2 to m2. ( ) ______ 100 cm 1 m X m2 = 41.2 cm2 = 0.412 m2 WRONG! = 0.412 cm.m Recall that… 41.2 cm2 = 41.2 cm.cm ( ) ______ ( ) ______ X m2 = 41.2 cm.cm 100 cm 1 m 100 cm 1 m = m2 ( ) ______ 100 cm 1 m 2 X m2 = 41.2 cm2 = m2

Convert 41.2 cm2 to mm2. Recall that… 41.2 cm2 = 41.2 cm.cm ( ) _____ ( ) _____ X mm2 = 41.2 cm.cm 1 cm 10 mm 1 cm 10 mm = 4,120 mm2 2 ( ) _____ 1 cm 10 mm X mm2 = 41.2 cm2 = 4,120 mm2

Measured dimensions of a rectangular solid: Length = 15.2 cm Width = 3.7 cm Height = 8.6 cm H W Find volume of solid. L V = L . W . H = (15.2 cm)(3.7 cm)(8.6 cm) = 480 cm 3

Convert to m3. cm.cm.cm ( ) _____ ( ) _____ ( ) _____ 100 cm 1 m X m3 = 480 cm 3 2 100 cm 1 m 100 cm 1 m = or ( ) _____ 100 cm 1 m 3 X m3 = 480 cm3 = m3 or 1 m cm ( ) _________ 3 X m3 = 480 cm3 4.80 x 10-4 m3 =

Convert to m3... Measured dimensions of a rectangular solid: Length = 15.2 cm Width = 3.7 cm Height = 8.6 cm 0.152 m 0.037 m 0.086 m H W Find volume of solid. L V = L . W . H = (0.152 m)(0.037 m)(0.086 m) = m 3

Convert to mm3.

= x 10-9 report -6.5 x 10-9 (2 sig. figs.) = x 103 or report 5.35 x 103 (3 sig. figs.) = x 10-13 report 5.84 x (3 sig. figs.) = x 1023 report 2.9 x 1023 (2 sig. figs.) = x 1016 report -3.1 x 1016 (2 sig. figs.)

Rule for Multiplication Calculating with Numbers Written in Scientific Notation When multiplying numbers in scientific notation, multiply the first factors and add the exponents. Sample Problem: Multiply 3.2 x by 2.1 x 105 (3.2) x (2.1) = 6.72 6.72 x 10-2 (-7) + (5) = -2 or 10-2 Exercise: Multiply 14.6 x 107 by 1.5 x 104 2.19 x 1012

Rule for Division Calculating with Numbers Written in Scientific Notation When dividing numbers in scientific notation, divide the first factor in the numerator by the first factor in the denominator. Then subtract the exponent in the denominator from the exponent in the numerator. Sample Problem: Divide 6.4 x 106 by x 102 . (6.4) (1.7) = 3.76 . 3.76 x 104 (6) - (2) = 4 or 104 Exercise: Divide 2.4 x by 3.1 x 1014 7.74 x 10-22

Rule for Addition and Subtraction Calculating with Numbers Written in Scientific Notation In order to add or subtract numbers written in scientific notation, you must express them with the same power of 10. Sample Problem: Add 5.8 x 103 and x 104 (5.8 x 103) + (21.6 x 103) = 27.4 x 103 2.74 x 104 Exercise: Add 8.32 x and 1.2 x 10-5 1.28 x 10-5

Using Scientific Notation for Expressing the Correct Number of Significant Figures Measurement Number of significant figures it contains Measurement Number of significant figures it contains 25 g 0.030 kg x 106 mg 6 x 104 sec g 20.06 cm 1.050 m 2 7 1 5 4 0.12 kg cm kg 6.00 x 106 kg 409 cm cm g 2 7 1 3 5 4

chemical reaction a rearrangement of atoms such that “what you end up with” products differs from “what you started with” reactants

Combustion of a Hydrocarbon carbon dioxide methane + oxygen  + water CH4(g) + 2 O2(g)  CO2(g) + H2O(g) 2 

sodium hydroxide sodium + water  hydrogen + 2 Na(s) + 2 H2O(l)  H2(g) + 2 NaOH(aq) 

Synthesis taking small molecules and putting them together, usually in many steps, to make something more complex Sunlight Carbon Dioxide Oxygen Glucose Water Photosynthesis CO H2O O C6H12O6

The International System of Units
Honors Chemistry Introduction to Chemistry The International System of Units Quantity Name Symbol Length meter m Mass kilogram kg Time second s Amount of substance mole mol Thermodynamic temperature Kelvin K Electric current amperes amps Luminous intensity candela cd Internet Access to the National Institute of Standards and Technology “To be or not to be”: the English or the Metric system The English system of measurement used today in the United States originated in the decrees of English monarchs. The French Revolution produced the overthrow of the French monarchy and in 1799 it also led to the creation of the set of weights and measures we call the metric system. The metric system was legalized for use in the United States in 1866 along with the traditional English system. Today the only countries in the world that do not use the metric system are the United States of America, Liberia and Myanamar. United States government policy toward the Metric System This part is to access the following URLs for the National Institute of Standards and Technology, NIST, and review the evolution of the relationship between the United States and the Metric System. You can answer the first question after reviewing this NIST page. What was the year when the United States signed the “Treaty of the Meter”? Access this FDA page to answer the following question. What does the term “Both timeless and toothless” have to do with the Metric Conversions Act of 1975? In your opinion does this influence the pace of metrification in the United States? Name ____________________ Hr ____ Another part of your assignment is to write a brief argument on the back of this page for adopting the metric system and replacing the English system. Lastly you are to write an argument for continuing the current pattern of using two systems. Argument for adopting the Metric system and dropping the English system. Argument for retaining both the English system and the Metric system Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 16

Derived Units Commonly Used in Chemistry
Honors Chemistry Introduction to Chemistry Derived Units Commonly Used in Chemistry Quantity Name Symbol Area square meter m2 Volume cubic meter m3 Force newton N Pressure pascal Pa Energy joule J Power watt W Voltage volt V Frequency hertz Hz Electric charge coulomb C

Area and Volume: Derived Units
Honors Chemistry Introduction to Chemistry Area and Volume: Derived Units Area = length x width = m x 3.0 m = 15 ( m x m) = 15 m2 Volume = length x width x height = m x 3.0 m x 4.0 m = 60 ( m x m x m) = 60 m3

Prefixes in the SI System
Honors Chemistry Introduction to Chemistry Prefixes in the SI System The Commonly Used Prefixes in the SI System Power of 10 for Prefix Symbol Meaning Scientific Notation _______________________________________________________________________ mega- M ,000, kilo- k , deci- d centi- c milli- m micro- m nano- n Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 118

1024 g 1021 g Earth’s atmosphere to 2500 km 1018 g Quantities of Mass 1015 g 1012 g Ocean liner Giga- Mega- Kilo- base milli- micro- nano- pico- femto- atomo- 109 g Indian elephant 106 g Average human 103 g 1.0 liter of water 100 g 10-3 g 10-6 g Grain of table salt 10-9 g 10-12 g 10-15 g 10-18 g Typical protein 10-21 g Uranium atom 10-24 g Water molecule Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 25

SI-US Conversion Factors
Honors Chemistry Introduction to Chemistry SI-US Conversion Factors Relationship Conversion Factors Length 2.54 cm 1 in 1 in 2.54 cm 2.54 cm = 1 in. and 39.4 in 1 m 1 m 39.4 in. 1 m = 39.4 in. and Volume 946 mL 1 qt 1 qt 946 mL 946 mL = 1 qt and 1.06 qt 1 L 1 L 1.06 qt and 1 L = 1.06 qt Dominoes Activity Mass 454 g 1 lb 1 lb 454 g 454 g = 1 lb and 2.20 lb 1 kg 1 kg 2.20 lb 1 kg = 2.20 lb and

Accuracy vs. Precision Scientists repeat experiments many times to increase their accuracy. Good accuracy Good precision Poor accuracy Good precision Poor accuracy Poor precision Systematic errors: reduce accuracy Random errors: reduce precision (instrument) (person)

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.

Errors Systematic Errors in a single direction (high or low) Can be corrected by proper calibration or running controls and blanks. Random Errors in any direction. Can’t be corrected. Can only be accounted for by using statistics. Systematic error is when you get the same mistake every time you perform a measurement, and random error is when the mistake varies randomly. It’s much easier to compensate for systematic error than for random error.

Accuracy Precision Resolution
Honors Chemistry Introduction to Chemistry Accuracy Precision Resolution not accurate, not precise accurate, not precise not accurate, precise accurate and precise accurate, low resolution -2 -3 -1 1 2 3 time offset [arbitrary units] subsequent samples

SI Prefixes kilo deci- 1/10 centi- 1/100 milli- 1/1000 Also know… 1 mL = 1 cm3 and 1 L = 1 dm3

SI System for Measuring Length
Honors Chemistry Introduction to Chemistry SI System for Measuring Length The SI Units for Measuring Length Unit Symbol Meter Equivalent _______________________________________________________________________ kilometer km ,000 m or 103 m meter m m or 100 m decimeter dm m or 10-1 m centimeter cm m or 10-2 m millimeter mm m or 10-3 m micrometer mm m or 10-6 m nanometer nm m or 10-9 m Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 118

Practice Measuring cm 1 2 3 4 5 4.5 cm cm 1 2 3 4 5 4.54 cm PRACTICE MEASURING Estimate one digit of uncertainty. a) 4.5 cm b) * 4.55 cm c) 3.0 cm *4.550 cm is INCORRECT while 4.52 cm or 4.58 cm are CORRECT (although the estimate is poor) By adding additional numbers to a measurement – you do not make it more precise. The instrument determines how precise it can make a measurement. Remember, you can only add ONE digit of uncertainty to a measurement. In applying the rules for significant figures, many students lose sight of the fact that the concept of significant figures comes from estimations in measurement. The last digit in a measurement is an estimation. How could the measurement be affected by the use of several different rulers to measure the red wire? (Different rulers could yield different readings depending on their precision.) Why is it important to use the same measuring instrument throughout an experiment? (Using the same instrument reduces the discrepancies due to manufacturing defects.) cm 1 2 3 4 5 3.0 cm Timberlake, Chemistry 7th Edition, page 7

Implied Range of Uncertainty
Honors Chemistry Introduction to Chemistry Implied Range of Uncertainty 5 6 4 3 Implied range of uncertainty in a measurement reported as 5 cm. 5 6 4 3 Implied range of uncertainty in a measurement reported as 5.0 cm. When the plus-or-minus notation is not used to describe the uncertainty in a measurement, a scientist assumes that the measurement has an implied range, as illustrated above. The part of each scale between the arrows shows the range for each reported measurement. 5 6 4 3 Implied range of uncertainty in a measurement reported as 5.00 cm. Dorin, Demmin, Gabel, Chemistry The Study of Matter 3rd Edition, page 32

750 740 760 5 10 Here is a final example, with the vernier at yet another position. The pointer points to a value that is obviously greater than and also less than Looking for divisions on the vernier that match a division on the scale, the 8 line matches fairly closely. So the reading is about In fact, the 8 line on the vernier appears to be a little bit above the corresponding line on the scale. The 8 line on the vernier is clearly somewhat below the corresponding line of the scale. So with sharp eyes one might report this reading as ± 0.02. This "reading error" of ± 0.02 is probably the correct error of precision to specify for all measurements done with this apparatus.

How to Read a Thermometer (Celcius)
Honors Chemistry Introduction to Chemistry How to Read a Thermometer (Celcius) 10 10 100 5 5 5 50 4.0 oC 8.3 oC 64 oC 3.5 oC

Record the Temperature (Celcius)
Honors Chemistry Introduction to Chemistry Record the Temperature (Celcius) 60oC 6oC 50oC 5oC 25oC 100oC 100oC 40oC 4oC 20oC 80oC 80oC 30oC 3oC 15oC 60oC 60oC 20oC 2oC 10oC 40oC 40oC 10oC 1oC 5oC 20oC 20oC 0oC 0oC 0oC 0oC 0oC A 30.0oC B 3.00oC C 19.0oC D 48oC E 60.oC

Rules for Counting Significant Figures 1. Nonzero integers always count as significant figures. 2. Zeros: There are three classes of zeroes. Leading zeroes precede all the nonzero digits and DO NOT count as significant figures. Example: has ____ significant figures. Captive zeroes are zeroes between nonzero numbers. These always count as significant figures. Example: has ____ significant figures. Trailing zeroes are zeroes at the right end of the number. Trailing zeroes are only significant if the number contains a decimal point. Example: x 102 has ____ significant figures. Trailing zeroes are not significant if the number does not contain a decimal point. Example: 100 has ____ significant figure. Exact numbers, which can arise from counting or definitions such as 1 in = 2.54 cm, never limit the number of significant figures in a calculation. 2 4 3 1 Ohn-Sabatello, Morlan, Knoespel, Fast Track to a 5 Preparing for the AP Chemistry Examination 2006, page 53

Significant figures: Rules for zeros
Honors Chemistry Introduction to Chemistry Significant figures: Rules for zeros Leading zeros are not significant. Leading zero 0.421 – three significant figures Captive zeros are significant. Captive zero 4012 – four significant figures Trailing zeros are significant. Trailing zero 114.20 – five significant figures

Significant Figures Number of Quantity Certain Uncertain Significant Digits Digits Figures g (thousandths) 6.02 mL (hundredths) m (thousandths) 7.5 g (tenths) 0.037 g (thousandths) g (ten-thousandths) 3 *The position of the decimal point has nothing to do with the number of significant figures. Ralph A. Burns, Fundamentals of Chemistry 1999, page 52

Basic Algebra Solve for x. ___ x BA = TR H One way to solve this is to cross-multiply. BAH = xTR 1 TR ( ) ___ Then, divide both sides by TR. BAH = xTR ___ BAH TR x = The answer is…

Solve for T2, where… P1 = 1.08 atm P2 = 0.86 atm V1 = 3.22 L V2 = 1.43 L T1 = 373 K ____ T1 P1V1 = P2V2 T2 1 P1V1 ( ) ____ P1V1T2 = P2V2T1 T2 = P1V1 ______ P2V2T1 T2 = (1.08 atm)(3.22 L) _____________________ (0.85 atm)(1.43 L)(373 K) = 130 K

A General Procedure for Solving Problems
Honors Chemistry Introduction to Chemistry A General Procedure for Solving Problems Read the problem carefully and make a list of the “knowns” and the ‘unknowns” Look up all needed information Your lecture notes will have much, if not all, of the needed information Work out a plan and, following your plan, obtain an answer by carrying out the required math. Check over your work This is best done by estimating your answer Ask yourself: “Does the answer seem reasonable?”

How to Succeed in Chemistry
Honors Chemistry Introduction to Chemistry How to Succeed in Chemistry Learn the language Use the illustrations Review your notes frequently Work as many problems as possible Do NOT cram for exams.

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