1 Chemistry Honors Chemistry Unit 1

2 What is Chemistry ~The science that deals with the materials of the universe and the changes these materials undergo. The study of the interactions of matter (atoms and molecules) and the energy involved

3 Gathering InformationObservation- a fact you use one of your five senses to determine (the thermometer reads 24o C, this font is white) Inference- something you reason out (Heat entered the liquid causing the temperature to rise) Inferences are not as reliable as observations but sometimes required.

4 Problem Solving 1. Recognize some problem, and clearly state it.2. Propose a possible solution to the problem, this is formulating a hypothesis. 3. Test your hypothesis by running some type of an experiment

5 Scientific Method ~A procedure for solving problems Gather informationForm a hypothesis Test your hypothesis Analyze your results Draw conclusion Repeat your work and share it with others

6 It is not an exact sequenceRepeat your work And share it with others Gather info Draw conclusion Form hypothesis Problem Analyze results Test hypothesis

7 Experiment There are many ways to experimentVariable- what you are testing only test one variable at a time A control group is necessary for an accurate comparison (the experiment without the variable) Blinded control groups don’t know they are the control Double blinded studies have patients who don’t know they are the control and experimenters who don’t know they are working with the control

8 Theories and Laws Common definitions of these words cause confusion.Theory- commonly is a hypothesis. An educated guess as to the solution of the problem. Law- a rule, that must be followed. THIS IS NOT THE DEFINITION OF SCIENTIFIC THEORY OR LAW!!

9 Theories and Laws Theory- attempts to explain why data gained from conclusions and observations are so. Law- summary of what is said in several conclusions and observations. Theories do NOT become laws! The names have nothing to do with level of acceptance.

10 Models Model- any representation of an object or a systemA theory is sometimes called a model as it explains helps to explain how something works. The theory or model of how a gas works would be countless tiny particles (atoms and molecules) moving about rapidly colliding with everything. This is the best possible accepted account for why gas act the way they do.

11 Laws A Natural Law is a summary statement.Like Charles’ Law, put simply, heating a gas makes it expand, cooling it makes it contract. There is no why in a Law, just what happens. A law is NOT a more proven version of a theory, it is a different type of a statement.

12 Lab Safety

13 In the event of an accident…REMAIN CALM!!!!!! Get someone who knows what to do. Don’t do anything “helpful” unless you are asked someone is in serious danger

14 Appropriate Dress Goggles Closed shoes—No Flip flops or sandals.Long hair must be tied back. Nothing dangling loosely from you.

15 Lab Safety Equipment Fire extinguisher Fire Blanket Shower Eye WashIf there is a large fire on equipment or the room If a person is on fire If a chemical is spilled on someone’s body (everyone but the victim will leave the room) If a chemical is in someone’s eyes

16 Other equipment First Aid kit Broom and dustpan broken glass bucketChemical Spill Clean up kit Gas turn off button Fire alarm for minor injuries for broken glass or metal all sharp objects go in here For chemical spills Turns off all gas to room in case of emergency pull

17 The Metric System and conversions

18 Why use the metric system?is it just to annoy American high school science students? It is used by (almost) the entire world except for the United States. (Myanmar and Liberia are the only other hold outs) Easy to replicate. Easier to convert between units.

19 The “SI” system length meter m mass kilogram Kg volume liter LSI is a subset of the metric system. SI stands for Systeme Internationale d’Unites or the International System of Units. length meter m mass kilogram Kg volume liter L temperature Kelvin/ Celsius K / C amount of substance mole mol

20 Metric Prefixes Name Symbol Meaning Tera T Giga- G Mega- M 1,000,0001,000,000,000,000 Giga- G 1,000,000,000 Mega- M 1,000,000 Kilo- k 1,000 Hecto- h 100 Deka- da 10 (base) Deci d 1/10 Centi- c 1/100 Milli- m 1/1,000

21 Converting between Units (Dimensional Analysis, Factor Label Method)to convert one unit to another you need conversion factors. Conversion factor- how much of one unit equals another unit Ex. 1 kg = 2.2 lb or 1000 m = 1 km Therefore 1 kg/ 2.2 lb = 1 or 2.2 lb / 1 kg =1 you can always multiply any number by one and not change the number

22 Write down your given and underline it. draw an H or a field goal post next to it. in any H or field goal post you can put one conversion factor (half on top half on bottom). put the unit you want to cancel out on the opposite side of the field goal. multiply by everything on top, divide by everything on the bottom. Convert 52 lbs to kg. (2.2 lbs = 1 kg) 1 kg 52 lbs = 23.6 kg 2.2 lbs lbs divided by lbs cancel out

23 1 yd = .9144 m How many meters are in a football field (100 yds)?100 yds yds 1yd .9144 m =91.4 m .9144m 1 yd no, the units you want to cancel have to be on the opposite side. yards divided by yards cancel out You can always do more than one step with this method. How many meters is 100 ft? (1yd = 3ft) 100 ft

24 1 kg = 2. 2 lb, 1000g = 1 kg 1000 mL = 1 L 30 mL = 1 fl oz, 31 kg = 2.2 lb, 1000g = 1 kg 1000 mL = 1 L 30 mL = 1 fl oz, 3.8 L = 1 gal How many kg are in 175 lbs? how many grams are in 175 lbs? The key to doing multi-step problems is figuring out a “plan of attack” in the last problem I can convert lbs kgg, then fill in your H’s to match How many fl oz are in .32 gal? (you will need 3 H’s)

25 If you have a unit expressed as a fraction..put the number and the numerator as the given, and write the denominator below the line, then proceed with the rest of the rules convert 250 g/L to g/mL Convert 42 km/hr to m/s

26 Mass Volume and Density

27 What is matter? Matter is what the universe is made of.Matter is anything that has mass and volume. Examples include just about everything (any solid, liquid or gas). Example of things that are not matter include electricity, sound and light.

28 What is the difference between mass and volume?Mass- how much matter is present Measured in Kg, g and mg Volume- how much space something takes up Measured in mL, L and cm3 Which weighs more a ton of bricks or a ton of feathers? Neither, they both have the same mass. However, the feathers will have a much higher volume.

29 The difference between mass and weight.Weight is the force of gravity pulling down on the mass of an object. Weight = mass x gravity and % of the time gravity is a constant (9.8 m/s2) A normal scale will divide for you and give you your mass However there are differences

30 Mass is inertia (resistance to change in motion) it has no direction.Mass is measured in kilograms (Kg). Mass never changes, unless you remove or add matter to the object. Weight is a force, it pulls in a definite direction. Weight is measured in Newtons (N) Weight changes with altitude. On the moon you would weigh 1/6 of what you do on Earth.

31 How to measure volume. If it is a cubic solid, measure length. width and height and multiply them. l x w x h = v If it is a liquid, pour it in a graduated cylinder and read from the meniscus (the low point of the curve). ALWAYS PUT YOUR HEAD AT THE SAME LEVEL AS THE MENISCUS air meniscus water

32 Measuring an irregular solidfirst pour water into a graduated cylinder large enough to hold the solid, and read its volume. then place the solid into the water being careful not to spill any water. read the new volume. subtract the new volume from the old for the volume of the solid.

33 How to measure mass If it is a “nonmessy” solid, weigh it on a scale.If it is a liquid or messy (a powder, greasy etc.) get a weighing tray or beaker. weigh the empty weighing tray or beaker and record its mass. add the object to the weighing tray or beaker and weigh it and subtract the mass of the empty beaker.

34 Scale Rules Gently place objects on scale.Make sure the scale is clean. (wipe off excess powder when done) Make absolutely certain before you use it it reads 0.00 g It if doesn’t press ON/ZERO If you press ON/ZERO after you place your weighing tray on the scale, you don’t have to subtract the mass.

35 Density Density is a ratio of mass to volume of an object.D= m / v (density = mass / volume) Density is measured in g/mL (grams per milliliter). Density of a pure compound or element is a constant Gold is always 19.3 g/mL, pure water is always 1.0 g/mL

36 Quick density test least dense most dense cork oil plastic water pennyless dense objects float in more dense objects. least dense most dense cork oil plastic water penny

37 Interesting point… Density of water is 1 g/mLThe density of steel is 7.9 g/mL What is the density of an aircraft carrier loaded with jets, crew, and guns? If it hasn’t been sunk it is less than 1 g/mL Boats have a hollow hull (big space for air to collect) to decrease their density. Air has a density of g/mL

38 Sig Figs Significant Figures

39 What are Sig Figs? I read in the paper that Jimmy Haslam (owner of the Browns) has a net worth 2.7 billion dollars. Myself and a friend bought 4 tickets for $264.30 Assume that immediately after it was reported, I ran to Mr. Haslam with cash. Jimmy gets every penny and hasn’t had another expense yet. Does that mean Jimmy Haslam now has exactly $2,700,000,264.30? Of course not, all of those 0’s were actually numbers that we didn’t report because we didn’t measure accurately enough. The number was rounded!

40 This is where sig figs come into playAbsolutely accurate measurements are impossible!!! We must round somewhere When we do calculations with these numbers we must reflect how accurate our initial numbers were. Significant digits means that digit was accurately measured Insignificant digit means that digit was NOT accurately measured.

41 Rules for determining if a digit is significantIf it is not a zero, it is significant.123 If a zero is between two significant digits, it is significant. 309 Zeros at the end of a number with a decimal point are significant. 56.0 Zeros at the end of a number that do not have a decimal point are NOT significant Zeros at the front of a decimal are NOT significant

42 Determine how many sig figs are in each number734 100,025 .00034 527.00 16.01

43 Round each number to the given number of sig figs(2) 734 (4) (3) (5) (4) (3) (5) 16.01 (3) 18700

44 How to report answers When adding or subtracting.When multiplying or dividing. You can only have as many sig figs in your answer as you do in the number with the least amount of sig figs. 3.56 x 2.1= 7.476 7.5 (2 sig figs) When adding or subtracting. Numbers added to or subtracted from insignificant numbers are insignificant (rounded off). 368.58 369 insignificant *Doing this will account for 1 point on every single test problem we do!!!!

45 Practice 6.74 x 2.1 3870 / 14.2

46 Exemptions from sig figssome numbers have an infinite number of sig figs. Meaning we can ignore them in our calculations If a something = 1(unit), that one has an infinite number of sig figs. 1 yd = m many conversion factors have an infinite number of sig figs, for example 3 ft = 1 yd, 60 sec= 1 min, 100 cm = 1m. Not all conversion factors have an infinite number of sig figs though. .9144 m = 1 yd, 2.2 lbs = 1 kg. If you are ever unsure, ask me!

47 Important Rule Only use sig figs in your answer.Do NOT round in the middle of the problem!!!

48 Scientific Notation some numbers so large or small that is a pain to write out normally for example Jimmy Haslam has $1,800,000,000 To write in scientific notation write down all sig figs x10x The number is always written to the ones place with a decimal so the above number is $1.8x109

49 Quick conversions 6.7 x10-7 2.31 x105 5.79 x103 4.19 x10-5 .006594,100,000 9,840

50 Scientific notation has to be used to correctly write some answersFor example 1329 / 13 = rounded to 2 sig figs would be… You Have To Write This Number In Scientific Notation! 1.0x102

51 scientific notation and your calculatorTo put numbers in scientific notation in your calculator there is normally an E or EE or EXP key That E EE or EXP replaces the x10 Pay attention to the way your calculator denotes scientific notation!!! To type 4.3x104, type 4.3[E]4

52 Accuracy and Precision

53 Difference between accuracy and precisionAccuracy- how close you are to the actual answer Precision- how close all of your answers are to each other Accuracy is a measure of your lab technique, precision is a measure of your ability to duplicate what you just did

54 Dart Board Metaphor high precision low accuracyhigh accuracy low precision high accuracy and precision low accuracy and precision

55 Measuring accurately always report all numbers given on a digital readout (Do NOT round) Do NOT add or delete zeros from the end! Make sure your reading is stable! Always read your equipment as accurately as you can (take your time, get close to the instrument.

56 Using a Graduated Cylinder.Pour the liquid in a graduated cylinder and read from the meniscus. The water will “grip” to the edges and form a depression in the middle, the lowest point of this curve is the meniscus. air ALWAYS PUT YOUR HEAD AT THE SAME LEVEL AS THE MENISCUS meniscus water

57 Reading between the linesEstimate one place on non digital equipment. (rulers, graduated cylinders) 6.60 cm cm 6.42 cm If it is exactly on the line

58 Reading between the linesEstimate one place on non digital equipment. (rulers, graduated cylinders) 6.90 cm cm 6.25 cm If it is exactly on the line

59 Reading between the linescm

60 Graduated Cylinder 20 mL 10 mL

61 What’s the difference between 6.6 cm and 6.60 cmThe difference is how accurately you were able to measure. More accuracy is always better but you can NEVER be exact You must report how accurate you were.

62 Measuring precisely If possible always measure three timesIf one measurement isn’t close to the others always measure again. It is always a good idea to have your lab partner take the same reading as you to make sure you are reading it correctly.

63 Matter ~anything that takes up space and has mass ~it normally comes in 3 phasesSolid Liquid Gas Definite shape, Definite volume lowest energy No definite shape, definite volume mid-level energy No definite shape, no definite volume high energy

64 Plasma “4th phase of matter”Most common phase of matter in the universe. Extremely high energy. Commonly found in stars, can be created naturally by lightning on Earth and the hottest part of a flame.

65 Chemical Reactions Process by which substances interact to form new substances. Reactants- substances you start with, or what reacts with each other. Products- substances that are created, or what is produced.

66 Chemical Reaction exampleBaking soda and vinegar react to form reactants Carbon dioxide, water and a salt products

67 Energy in Chemical ReactionsEndothermic Exothermic Give off energy Products have less energy than reactants The substance gets hotter Explosions, fire Take in energy Products have more energy than the reactants The substance gets colder Cooking food, instant ice packs *although it is theoretically possible for the energy to be the same on both sides of the equation, in all known cases there is at least a slight difference.

68 Physical Properties Any property that can be tested without changing the chemical make-up of the substance. For Example- mass, weight, density, volume, color, shape, texture, melting point, and boiling point. Changing phases does not change the chemical make-up of a substance. When water freezes to ice, it is still water (H2O).

69 Chemical Properties Any property that can only be tested by changing the chemical make-up of the substance. Flammability, chemical reactivity, and ability to rust. A chemical change always involves a change in energy (either endothermic or exothermic).

70 A quick statement You can tell a chemical reaction has occurred if the products are different from the reactants! If there is no change it is NOT a reaction! e.g. ice melting is NOT a reaction, it is a physical change!

71 Observations that indicate a Chemical Change has taken placeProduction of a gas (bubbles) Change in color Formation of a precipitate Precipitate- solid falling out of solution Evolution of energy Change in temperature Release of light etc.

72 Chemical or Physical Changes are when you change a chemical or physical propertycutting a piece of ice in half physical change activating an instant ice pack (make it cold) chemical change melting ice baking flour, sugar, egg and water together

73 Physical Properties can be used to separate mixturesdepending on the shape and size you may be able to separate them with a filter, or a centrifuge solutions require distillation (boiling substances off one at a time) chemical properties could also be used to separate mixtures

74 Only chemical properties can be used to separate compoundsthe atoms are bonded together so you must break these bonds to separate the molecules to atoms or smaller molecules. If you pass an electric current through water you will separate it into H2 and O2 this is called electrolysis

75 Classifying Matter

76 Classifications Matter can be classified as an element, compound or mixture Elements- substances consisting of entirely the same atom. Compounds- substances consisting of entirely the same molecule. Mixtures- elements and/ or compounds next to each other

77 Elements There are 90 naturally occurring atoms on Earth about only 40 of those can be found naturally in elemental form Hydrogen, copper, gold, magnesium, lead, oxygen, nitrogen, helium, etc. Elements are represented by a 1-2 letter symbol The first must always be a capital letter, and the second (if present) is lower case.

78 Common element symbolsFe Au Cl H Cu C Ag oxygen- iron- gold- chlorine- hydrogen- copper- carbon- silver- *notice, that this is not written as FE, make that 2nd letter lower case not a small capital. A complete alphabetical list is located in the front cover of your book

79 Korean Periodic Table

80 We will not have to memorize the entire periodic tableHowever you will be responsible to know all element symbols with an atomic number (Hydrogen to Krypton) and Silver (Ag), Gold (Au), Mercury (Hg), Tin (Sn), Iodine (I), Uranium (U), Plutonium (Pu), and Lead (Pb) You don’t have to remember where they go on the periodic table or their information, only the symbol and name.

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82 Quiz There will be a quiz sometime next week on these.It will say Fe_______ Or Copper ______ Whatever grade you get on the quiz will go in progressbook and will not change, however, if you don’t get 90% or better I will make keep retaking a different version until you do or you can’t complete labs.

83 Compounds -substances made up entirely of the same molecule.molecule- 2 or more atoms bonded together. these are represented by chemical formulas element symbols and subscript numbers. H2O hydrogen (2 of them) oxygen subscript numbers mean there are that many of the atom it is directly behind. If there is no subscript number then 1 is implied. water, ammonia, glass, methane and limestone

84 Here is where capitalization becomes really important1 carbon, 2 oxygen carbon dioxide ( a gas) 2 cobalt atoms cobalt is a metal

85 Some elements can have molecules as their smallest componentas long as the molecule is made up entirely of the same atom The oxygen we breathe is not 1 oxygen atom, it is O2 When 2 atoms are joined like in the above case, it is called a diatomic element The 7 diatomic elements are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine

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87 Allotropes allotrope -one of the different molecular forms of an element oxygen has 2 allotropes O2 and O3 (ozone) carbon has several allotropes graphite, diamond, buckyball (found in soot)

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89 Mixtures compounds and/or elements mixed together but not bonded together heterogeneous mixture- different throughout or chunky granite, orange juice with pulp, Italian dressing homogeneous mixture- even throughout milk and saltwater Solution really well mixed homogeneous mixtures

90 Breakdown of classification

91 Separating Compounds Separating MixturesMixtures can be separated by chemical or physical means Separating Compounds compounds can ONLY be separated by chemical means (requires a chemical change)

92 Separating Elements atom is from the Greek word atomos, meaning not able to be cut. elements can NOT be separated by chemical or physical means. The only way to separate an atom is through a nuclear reaction.

93 Energy and Chemistry

94 Law of conservation of energyEnergy can neither be created nor destroyed, it can only change forms. An exothermic reaction releases energy, where did it come from? The energy holding the molecules of the reactants together (bonds). The products need less energy to be held together so the energy is released to the area surrounding the reaction.

95 Endothermic reactions absorb energy, where does that come from?~from the area surrounding the reaction. That is why it ends up feeling colder. In both cases energy is conserved, it is either donated to another system or taken from another system.

96 Energy Changes All chemical reactions (chemical changes) involve a change in energy Physical changes also involve a change in energy We are only going to look at phase changes

97 Heat energy Atoms/molecules in a substance are not stationary, they move around. Heat energy in an object is the rate of motion of atoms/molecules in a substance The faster the particles are moving the more heat energy the substance has.

98 Energy in phases Solid- atoms/molecules vibrate in one place, occasionally sliding by one another. ~students in detention Liquid- atoms/molecules move freely with more energy within a confined volume. ~students in the cafeteria Gas- atoms/molecules move around wildly constantly running into each other. ~football practice

99 Causing phase changes To go from solid  liquid gas you…add energy (from another system) to turn ice into water you heat it, to turn water to steam you heat it. To go in the reverse direction you remove energy. (there is no cold energy you can add)

100 Matter without heat energyIf you continually cool (remove energy) an object, eventually the object will have no more energy. This is called absolute zero. It is when all motion (of the particles) stops. It should occur at o C or 0 K or o F Cornell and Wieman cooled a sample to K

101 Temperature A measure of intensity of the heat energy in an object.It is an average of how fast the particles are moving within an object. It is measured in Celsius (centigrade) or Kelvin scale. Kelvin = Celsius + 273

102 Matter and energy connectionmatter can be converted into energy. you can calculate by the equation: E = mc2 energy = mass x (speed of light)2 speed of light = 3.0 x108 m/s This is in Einstein’s theory of special relativity. This happens in all energy transfers but normally the difference is too small to measure