Welcome to CHM 115

1. Welcome to CHM 115 • Dr. Peters (Office 268 SLC) x4621 (also have a lab…SLC 253, extension is ??) • Office Hours in syllabus (and by appt.) • Policy is an “open door”. Stop by whenever—if the door’s open; then come on in. • E-mail address: peters@wilkes.edu • Other mechanisms…AIM “chemprofgreg” • Facebook—On occasion I go there to see what’s what. • This is section C MWF—1300—1350 (MWRF) • Meeting on Thursday in SLC 101 (the big room) • Syllabus—Posted on-line (more on that in a minute).

2. Help with the first day? • Some will warn you that “this isn’t HS”, or not Grade 13. I WELCOME you to the challenge!! • I have faith that you can do this….just takes some work • Here’s a list of random information about me/this class • I don’t offer “extra credit” when you bomb a test… • I don’t drop tests…ever. I know that some people develop an acute case of “I don’t take tests well”…test anxiety…whatever. • The point of class is not “to build your self-esteem”, it’s to learn the material you will need to be successful in this and other classes • Engineers? Build a bridge/levy properly…you don’t GET 2nd chances • Bio/Chem/Pharm? Mistakes there can kill…

3. More on the 13th grade thing • “I don’t understand word problems” • Translation: I don’t want to think at all…just tell me the answer or how to do it. • Alternate translation: I never actually solved anything in HS, I only applied a given formula and plugged it into my TI-83 • “But I got an “A” in AP Chemistry!!” • Translation: no standard curriculum exists for APC, I have no idea if you merited that grade or if your track coach taught APC and you won state twice in discuss. • “But I studied for 2/4/6 hours for your exam” • Idiotic comments like these indicate you have never prepared for anything in your life…look at your HS habits… • “But that’s the answer my calculator gave me!” • Translation: your calculator is smarter than you • “Will this be on the test?” Answer…Yes.

4. Other things to cover • Syllabus—posted on-line (many things will be posted there this year) • www.chem.wilkes.edu • Faculty • Greg Peters • Home page—in reality…just google “Peters Wilkes”! • Exams (final is outlined in Wilkes Calendar) • Labs—I’ve got the lab section on T, 0800 hrs. • Note—CHM 113 begins this week (check-in) • Note #2, M sections don’t meet NEXT week • Note #3--http://www.chem.wilkes.edu/~mencer/chm113home.html • Calculators—this is a science class, use a scientific calculator…No TI-83’s or above.

5. Background Information • Eating/Drinking in class. Be considerate of others near you. Or bring enough for ALL • Attendance—you’re all adults. Come to class or not—your choice. • TURN OFF YOUR PHONES • Don’t get me wrong, LOVE my cell…but not during class. • I know you just can’t wait to get that text message…it’s just rude • Can’t use it on an exam (as a calculator—yeah, right!!)

6. Background Information • We assume you have sufficient background in the following—after all, you scored well on placement exam • Algebra—this is a minimum • Dimensional analysis (trust me, you’ll need it) • Also called unit conversion… • Scientific (exponential) Notation/Sig Figs • Metric system…book has the conversions) • I can teach you the chemistry if you have the background—despite the obstacles…and chemistry has PLENTY of obstacles…such as…

7. People HHAATTEE chemistry • Feel Geek quota has already been met • Nobody else in the civilized world likes this stuff, why should I? • Um…Dr. Peters, in case you didn’t notice…This $#!+ is hard! • Chemistry (all words—Chemical) are dirty

8. Chemistry Misconceptions • Mad scientist…bubbling cauldron…ruling the world… • Just a bunch of memorization (actually a logical group of ideas that readily flow to create a coherent message) • I detest straight memorization as a learning technique. • There ARE, however, several things that you WILL HAVE to know (yes, that means committed to memory). • Density of water—1.00 g / mL (ooo…stop me when this gets tough) • Some others, and I’ll cover these in a minute • A few metric conversions • Can’t do anything with a chemistry degree

9. How to Study Chemistry (aka—how to get better grades) • Definitions—chemistry is a different language, learn to speak it or get smoked! • Yes, make a list of all the new words and define them, your text has them defined in the back • Assessment goals at the BEGINNING of each chapter!! This is a powerful way of zeroing in on what’s most important • Taking notes/class attendance—too simple • Dead giveaways—I emphasize what I want you to know (with an *--or “you should know this”)

10. More on the grade thing • Units—trip people a lot. Can’t understate the importance of keeping track of units • THINKING—sounds too simple, but ask yourself “does my answer make sense?” • Yes, people have earned a “Here’s your sign” on exams • Problems—I will assign homework problems from the back of the book. Doing them helps • Former students have said “it’s essential!” • Calculator crutch—do you use your calculat’r as a FIRST resort. If so, you’ll get it wrong • Your TI-83s are STUPID!! They don’t THINK FOR YOU!!!

11. Stuff I think you ought to know • I told you before, I hate memorization. But there are some things you just MUST know. How you choose to learn these things…your choice, but I consider these facts mandatory. (read: testable at any time) • Last spring, I asked the SAME question on EVERY exam, and some people STILL got it wrong on each exam…and I told them that question was going to be on EVERY exam!! • Choices…put this information into • comp notebook • Notecards…either way…I consider this material textable (AT ANY TIME!!) • If you’re ready…here we go.

12. Fast facts…quick and simple stuff • Chemical symbols and the elements they represent. • #’s 1-20…you should know these, I expect you to know them • Other more common elements/symbols? • Zn (zinc), Au (gold), Ag (sliver), Pb (lead), As (arsenic), Hg (mercury), U (uranium), Pu (plutonium) • Common household items… Ammonia NH3, ammonia Hydrogen peroxide H2O2 Benzene C6H6 Gypsum/marble/granite CaCO3 calcium carbonate Rotten eggs H2S, hydrogen sulfide Prestone (OH)CH2CH2(OH), ethylene glycol Table salt (NaCl) sodium chloride Baking soda Na(HCO3), sodium bicarbonate Drinking alcohol CH3CH2OH, ethanol Wood alcohol CH3OH, methanol Rubbing alcohol CH3CH(OH)CH3, isopropyl alcohol Vinegar CH3COOH, acetic acid (sol’n)

13. Compounds and Structures • I think you should know the following compounds, and their structures…including the ones on the previous page • Acids and the carbonate ion…

14. Bases and other simple molecules • Hydroxides—all common ones, Na, Mg, Ca, K, Ba • Gases & Diatomic molecules • N2, X2, O2, H2, NH3, CO, CO2, He, Ne…, • N2—80% of the atmosphere (O2 the other) • Halogens • Noble gases • Hydrogen (difference between H2 and He)

15. Scientific Measurements: SI Prefixes • Prefixes are used to indicate powers of ten of common units that are much smaller or larger than the base unit. • Although there are many prefixes, only a few are in very common use. • In measurements, kilo-, centi-, and milli- are the three most common prefixes.

16. What is the length in millimeters of a 1.25-ft rod? • What is the volume, in cubic centimeters, of the block of wood pictured here?

17. Density: A Physical Property and Conversion Factor Density is the ratio of mass to volume: m d = ––– V Density can be used as a conversion factor. For example, the density of methanol is 0.791 g/mL; therefore, there are two conversion factors, each equal to one: 1 mL methanol –––––––––––––– 0.791 g methanol 0.791 g methanol –––––––––––––– and 1 mL methanol

18. A beaker has a mass of 85.2 g when empty and 342.4 g when it contains 325 mL of liquid methanol. What is the density of the methanol? • How many kilograms of methanol does it take to fill the 15.5-gal fuel tank of an automobile modified to run on methanol?

19. Sample problem If the mass of the zinc added to the graduated cylinder is 30.0 g, find the density of zinc

20. YOUR TURN…Solve the following • The melting point of mercury is —38.4 °C • Convert to °F • A 5.79 g piece of Au (d = 19.4 g/cm3) is flattened to cover an area of 44.6 cm2 • How thick is this gold leaf? • Ships (despite the failure of the Titanic) are made of steel—which is much denser than water. Why don’t ALL ships just sink like a hunk of metal?

21. Yes…Getting Started: Key Terms • Chemistry is the study of the composition, structure, and properties of matter and of changes that occur in matter. • Matter is anything that has mass and occupies space. • Matter is the stuff that things are made of.

22. Oxygen molecule Water molecule Key Terms • Atoms are the smallest distinctive units in a sample of matter. • Molecules are larger units in which two or more atoms are joined together. • Examples: Water consists of molecules, each having two atoms of hydrogen and one of oxygen. • Oxygen gas consists of molecules, each having two atoms of oxygen.

23. Key Terms • Composition – the types of atoms and their relative proportions in a sample of matter. • The composition of water is two parts (by atoms) of hydrogen to one part (by atoms) of oxygen. • The composition of water is 11.2% hydrogen by mass, 88.8% oxygen by mass. • (Why the difference? Because hydrogen atoms and oxygen atoms don’t have the same mass!) • More on mass composition in Chapter 3.

24. Atoms Molecules make up ALL MATTER which exists as Substances Mixtures which may be which may be Elements Compounds Homogeneous Heterogeneous Classifying Matter

25. Classifying Matter • A substancehas a definite or fixed composition that does not vary from one sample to another. • All substances are either elements or compounds. • An element cannot be broken down into other simpler substances by chemical reactions. • About 100 elements known at this time • Each element has a chemical symbol: O, H, Ag, Fe, Cl, S, Hg, Au, U, etc. • A compound is made up of two or more elements in fixed proportions, and can be broken down into simpler substances. • Carbon dioxide, sodium chloride, sucrose (sugar), etc.

26. Classifying Matter • A mixture does not have a fixed composition. • A homogeneous mixture has the same composition throughout, though the composition of different homogeneous mixtures may vary. • Soda pop, salt water, 14K gold, and many plastics are homogeneous mixtures. • 10K gold and 14K gold have different compositions but both are homogeneous. • A heterogeneous mixture varies in composition and/or properties from one part of the mixture to another. Adhesive tape, CD, pen, battery, chair, and people are examples of heterogeneous mixtures. Most everyday “stuff” is mixtures.

27. On Tap for Today… • OK…so we have a dirt simple quiz later, but before we get there…let’s cover the structure of the atom • Dalton’s Atomic Theory • Constant Composition…Conservation of Mass • Rutherford…shatters some preconceived notions

28. Laws of Chemical Combination • Law of Conservation of Mass • The total mass remains constant during a chemical reaction. • All due respect to Einstein… • Law of Definite Proportions • All samples of a compound have the same composition, or … • All samples have the same proportions, by mass, of the elements present.

29. Dalton’s Atomic Theory Proposed in 1803 to explain the law of conservation of mass, law of definite proportions, and law of multiple proportions. • Matter is composed of atoms:tiny, indivisible particles. • All atoms of a given element are the same. • Atoms of one element differ from atoms of other elements. • Compounds are formed when atoms of different elements unite in fixed proportions. • A chemical reaction involves rearrangement of atoms. No atoms are created, destroyed, or broken apart.

30. Thomson—electrons…discharge tube Discharge tube…deflection of the rays in an electric and magnetic field Concluded these particles were subatomic (called electrons) 1/1800th of the mass of a hydrogen atom.

31. Rutherford elucidates the nucleus Gold foil, diffuse/spread out positive charge… Turned the ‘plum pudding’ model on its ear. Forced a new model of atomic structure Celebrates its centennial this year!

32. How are they arranged? • An atom has a dense central core, called the nucleus, and is composed of protons and neutrons. (marbles in Fenway Park) • Electrons surround the nucleus, occupy most of the volume of an atom, but have very little mass (relative to protons/neutrons) • An atom has no net charge, positively charged protons are balanced by electrons

33. Atomic Number/Atomic Mass • Number of Protons—atomic number (gives you the identity of the element) • Number of Protons/Neutrons gives you the Atomic Mass • Electrons? Don’t matter… for the mass anyway.

34. Electrons—how are they arranged? • Arranged in roughly spaced concentric shells. Called electron configurations. • Outer shells of electrons are called valence electrons (we will discuss this at some length for the rest of the semester). • Unfortunately we now must delve into some physics, a necessary and very worthwhile discussion… • Foreshadowing…we put electrons into orbitals, very specific ones. • These orbitals dictate a lot of the behavior we see in atoms.