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Intro to Chemistry. Chapter 1, section 3 and Chapter 2, and 2 formulas from Chapter 3 A Preview of Coming Attractions. RIGOROUS . ONLY INTENDED FOR MATURE STUDENTS!. http://bcjmedia.com/wp/wp-content/uploads/2011/08/trailer_green_screen_share.jpg. Do last!. Taking notes.
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Intro to Chemistry Chapter 1, section 3 and Chapter 2, and 2 formulas from Chapter 3 A Preview of Coming Attractions
RIGOROUS ONLY INTENDED FOR MATURE STUDENTS! http://bcjmedia.com/wp/wp-content/uploads/2011/08/trailer_green_screen_share.jpg
Do last! Taking notes... Summary Section…one or two sentences about this page of notes CUES 1-2 words CUES Main part for Notes . . . Use bullet points . . . . . .. Abbreviate . . Draw pictures to . help you. . . You do not have . to write in . complete . sentences. Main Part for Notes • Take notes in the MAIN part of the page. • The CUES are hints. Cover up the main part and see if the cues help you to recall that information when you study. • The SUMMARY is what the page is all about. Or you can add something later in this part. • Use loose leaf paper and a binder. Do 2nd Do this part first.
化学 • Chemistry in Japanese • Literally means “change study.” • Chemistry is the study of matter: the composition of matter and the changes matter undergoes. • Did you start taking notes yet?
Quimica • Chemistry in Spanish • From Google Translate… • La química es el estudio de la materia: la composición de la materia y la materia sufre cambios.
химия • Chemistry in Russian • From Google Translate… • Химии является изучение вопроса: состав вещества и материи подвергается изменениям.
Chemistry is not relevant to my life. Am I ever going to use THIS? How should I know? But since Chemistry is all around you, I’m going to guess YES. Do you like to cook? Do you want a pool?
Chapter Outlines: 1 for each Unit. • Read and outline the chapters. Chapter 3 outline is due on Friday (yes, this Friday!). Ignore the portion on “specific gravity.” • 2 pages front and back…minimum! • Don’t just copy random sentences from the book. Actually read the chapter. Rewrite it in your words, so you understand what you wrote. • Don’t worry about understanding EVERYTHING the first time. No one ever does (that included me when I was in your shoes). • If you have to re-read the Chapter 2-3 times, do it! That’s what the really successful students do. • The outline is YOUR NOTES from reading the chapter. • Add to those notes when I lecture in class.
The Scientific MethodChapter 1.3 • Observation • Use your senses to make observations and suggest questions. • Hypothesis • A testable “educated guess.” • Experiment • Supports and proves your hypothesis (or doesn’t support and disproves)
The Scientific Method • Analysis of Data • Analyze data collected during the experiment. • Conclusion • What happened? • Was your hypothesis supported or not (try NOT to think of it as success vs failure)? • How could you improve your experiment? • How could you expand upon your original experiment?
Scientific Theory • Theory • A detailed explanation explaining why an experiment works the way it does. • A theory can never be PROVEN completely true. • A theory can always be disproved if new data doesn’t support the theory. • If that happens, theory needs to be revised or discarded.
Scientific Theory • Theory • It doesn’t matter how many scientists believe it. Believing it is true doesn’t make it so. • Consensus isn’t science. The only thing that matters is if the scientific data supports the theory.
Scientific Law • Law • A law is a statement of fact, usually concerning a natural phenomenon. • It doesn’t explain how or why. • Theories explain. Laws don’t explain. They just tell you what it is. • Lets talk about an important law:
The Law of Conservation of Mass • In any chemical reaction or physical change, matter can neither be created nor destroyed. • The amount of matter (mass) doesn’t change. • However, the identity of the matter (what type of substance it is) could change. • mass of the reactancts = mass of the products
Chapter 2 • Back to matter… • Matter can be broken down into substances and mixtures. • Substances are pure. • Elements (smallest part of an element is an atom) • Compounds (smallest part of a compound is a molecule)
Substances vs mixtures • Carbon is a substance. • Water is a substance. • Air is a mixture of substances (O2, N2, CO2, etc)
Substances vs mixtures? • You try some • Methane (natural gas) • Coffee • Copper • Salt • Dirt • Sand
Substances: Elements • Elements are on the Periodic Table. • 118 elements exist • 90 occur naturally (1-92 except for 43Tc and 61Pm) • Elements 93 and higher are man made (most of them by Dr. Glenn Seaborg)
Substances: Compounds • Compounds are pure substances too. Common compounds are: • Salt (sodium chloride) • Sugar (sucrose) • Baking Soda (sodium bicarbonate) • Sand (silicon dioxide) • Rubbing Alcohol (isopropanol) • Carbon dioxide
Ionic Compounds vsMolecular Compounds • There are 2 types of compounds • Ionic compounds have ionic bonds and are composed of positive and negative ions. • Ions are formed when atoms lose or gain electrons. • Molecular compounds have covalent bonds. • Electrons are shared between atoms. There are no ions or charges.
Substances: Elements and Compounds • How do you tell if it’s an element or a compound? • An element cannot be broken down into anything simpler. • A compound can be separated into smaller elements. You must use a chemical reaction to break down a compound.
Compound vs Mixture • How do you tell if it’s an compound or a mixture? • A compound is bonded together. You must use a chemical reaction to break down a compound into elements. • A mixture isn’t bonded together. The substances are just mixed together. A mixture may be separated by physical separation techniques.
What are physical separation techniques? • Evaporation—can separate DISSOLVED solids from the liquid. • Filtration—can separate UNDISSOLVED solids from the liquid. • Decanting—can separate a dense undissolved solid from the liquid (because the solid is on the bottom and so you can pour off the liquid).
A physical separation technique sometimes tested on the SOL. • Chromatography • Can be used to separate a mixture of solids dissolved in a liquid. • Ink • Natural dyes
Chemical Reactions • Reactants Products • You can have 1 or more reactants • You will produce 1 or more products • How many you need and how much you produce is characteristic of the specific reaction. • We will study 5 major types of reactions starting in Chapter 8. • Chemical reactions are PERMANENT and NOT reversible.
Physical Properties • Matter has both physical and chemical properties. • Physical properties can be observed without CHANGING the type of matter. • When solid water (ice) melts it becomes liquid water. A change of state is a physical change (Δ or delta means change). • Physical changes are NOT permanent and are reversible.
Chemical Properties • Chemical properties can be ONLY be observed BY CHANGING the type of matter. • When salt (NaCl) is dissolved in water, a solution is formed. That is a physical change. The salt is still salt and the water is still water. You can separate them easily by evaporating the water.
Chemical Properties • But when sodium oxide (Na2O) is dissolved in water a solution is formed at first, but then a chemical reaction occurs. That is a chemical change. Sodium oxide reacts with water to form sodium hydroxide (NaOH). If you evaporate the water, you will have solid NaOH not Na2O. • We write that reaction as Na2O + H2O 2 NaOH
Why does one react and the other doesn’t? • Well, that’s chemistry. It’s not all that complicated but the answer won’t make much sense right now. • But, by the end of the course (Jan or June) it will make a lot of sense.
NOW: STUDY HARD!! 15-30 minutes every night! After you do all your reading and homework, etc. If you do, you won’t end up looking like this poor kitty when I hand you the test. You should plan on studying hours for EVERY chemistry test. But it doesn’t all have to be done the night before.
Helpful Hints • Take it one step at a time. You can’t do Chapter 19 in your book until you have completed most of the first 18 chapters. • Break down complicated words and sentences into terms that you understand better. Don’t just copy what the book says into your notes. Rewrite it in your words, so you understand what you wrote. • Know the VOCAB. I know it, and I’m going to use it. If you don’t understand the words, you won’t know what I am talking about. • Scientists love big words. They think it makes them sound really smart. But learn these words, and you’ll sound just as smart as they do.
Chemistry Builds on Itself • If you don’t understand what we are doing today, you aren’t going to get it tomorrow, because what we learn tomorrow will depend on what we learned today. • Google if you don’t understand something! • Ask questions! • Form study groups. Help each other learn! • That’s what you do naturally when YOU WANT TO LEARN something. You look it up. You ask someone. You figure it out! It works for Chemistry too (and other stuff you really don’t care about).
It takes Time, and Work and EFFORT! • It took over 250 years of hard work by thousands of brilliant scientists to “figure out” Chemistry! • How are you going to learn it in 5 minutes once a week?
Chemistry (or Schwartz) is too Hard or There’s Math in Chemistry! • It’s not and I’m not. • But it will be and I will be IF you don’t do your job. • Sometimes, this will seem like your second math class. • Let’s do some math! This puzzle is UNSOLVABLE, but Chemistry is SOLVABLE, if you work.
Density • Anyone remember the formula for density? • Anyone remember the “density heart?”
d = m / VOMG, we just zoomed into Chapter 3 • Density equals mass divided by volume. That’s what the formula is telling you. (Most of you probably already knew that). • Density has units of “g/mL” or “g/cm3” • Mass has units of grams (g). • Volume has units of milliliters (1 mL = 1cm3) • But what does density really mean? Density tells you how much 1 milliliter (volume) is going to weigh. • One mL of water weighs 1 g. One mL of gold weighs 19.3 g. Write this down and learn it!
d = m / V • If you know 2 of those 3 variables, you can solve for (calculate) the remaining one. This is basic, basic algebra 1. • Rearrange the formula so that mass is by itself. • Rearrange the formula so that volume is by itself.
d = m / V • If you know 2 of those 3 variables, you can solve for (calculate) the remaining one. This is basic, basic algebra 1. • Rearrange the formula so that mass is by itself. • Rearrange the formula so that volume is by itself. m = V xd
d = m / V • If you know 2 of those 3 variables, you can solve for (calculate) the remaining one. This is basic, basic algebra 1. • Rearrange the formula so that mass is by itself. • Rearrange the formula so that volume is by itself. m = V xd V = m / d
d = m / V • If you know 2 of those 3 variables, you can solve for (calculate) the remaining one. This is basic, basic algebra 1. • Rearrange the formula so that mass is by itself. • Rearrange the formula so that volume is by itself. • Write these into your notes. m = V xd V = m / d
d = m / V • If you know 2 of those 3 variables, you can solve for (calculate) the remaining one. This is basic, basic algebra 1. • Rearrange the formula so that mass is by itself. • Rearrange the formula so that volume is by itself. • You don’t need to memorize all 3. Memorize the top one and rearrange when you need one of the others! m = V xd V = m / d
K = °C + 273 • This formula converts Celcius temperature into Kelvin temperature. • This will be on the SOL. • For some problems in Chemistry, we need to use Kelvin temperature. • We don’t use Fahrenheit temp. If this is first semester, it’s probably about 80°F outside (maybe 30°F it is second semester). But you do need to know how to convert from Celcius to Kelvin (and vice versa). • What is the formula if you want °C by itself?
K = °C + 273 • This formula converts Celcius temperature into Kelvin temperature. • This will be on the SOL. • For some problems in Chemistry, we need to use Kelvin temperature. • We don’t use Fahrenheit temp. If this is first semester, it’s probably about 80°F outside (maybe 30°F it is second semester). But you do need to know how to convert from Celcius to Kelvin (and vice versa). • Answer: °C = K − 273
Remember… What you actually learned today is… What you have left after you forgot all the other stuff I told you. Learning requires real effort on your part. Some kids think “learning” means “teaching yourself.” They are right. I can’t MAKE you learn. But, I am here to help you learn!