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Page 1 Welcome to AP Chemistry! I hope you are ready for a fun, yet challenging year. You already have a solid background in basic chemistry from your first year Chem class, and this is critical to success in AP Chem. As the year progresses and you develop your skills for making connections and problem solving as we delve into great depth of the study of matter and the changes it undergoes, you will really begin to understand why chemistry is called the central science, and you will be able to apply your learning to all sorts of different situations. Students who finish AP Chemistry come out with a much better understanding of the world around them. They also come out with a sense of great accomplishment. AP Chemistry is a difficult class, but with determination and perseverance, you will surely succeed! 1. Purchase your own copy of 5 Steps to a 5 on the AP: Chemistry, John T Moore, McGraw Hill. (You can purchase them at Amazon.com Online, probably the more recent the publication the most current information however any version will work.) 2. Buy a few color highlighters. 3. Read and study thru the chapter titled ‘How to Approach Each Question Type’. Highlight material that applies to you. These sections give advice on what to expect and how to study. 4. Take the Diagnostic test. (Go ahead and write in the book, I will make an additional copy of this test for you to take before the AP Exam.) 5. Take a look at the AP and other websites given in this summer packet. List the three most useful in the front cover of your book. 6. Read and study (highlight, take notes in the margin, etc) and do all the review questions at the end of the chapter for these two sections (Chapters vary based on publication year of your 5 Steps to a 5). Basics Stoichiometry AP Chemistry is a difficult course. It is not all about memorization; however, having these items memorized is essential for success in learning the concepts covered in the course. Make flashcards, have your friends and family quiz you, take the lists with you on vacation, or do whatever it takes to get this information firmly planted in your head. Do not wait until the night before school begins. To give yourself a jump start in the course I recommend seven areas of memorization before the first day of class: 1. Diatomic molecules (7) 2. Polyatomic Ions (including name, symbol and charge) 3. Variable Valences for Transition Metals 4. Rules for Naming Acids 5. Rules for Naming Ionic Compounds 6. The Solubility Rules 7. Determining Oxidation Numbers Page 2 AP CHEMISTRY SUMMER ASSIGNMENT The following topics are included in this summer assignment: - You should memorize the 7 diatomic molecules. When alone and uncharged, the following substances exist as diatomic molecules: hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. There are 7 and they form a 7 on the periodic table (with the exception of hydrogen). Whenever you write the formula for these diatomic molecules it should look like this: H2, N2, O2, F2, Cl2, Br2, I2. Remember to name them with just the element name. - Scientific (exponential) notation - Significant figures - Naming compounds and Writing formulas from names - Balancing equations - Basic chemical conversions - Basic Stoichiometry Things to memorize for AP Chemistry: AP Chemistry is a difficult course. It is not all about memorization; however, having these items memorized is essential for success in learning the concepts covered in the course. Make flashcards, have your friends and family quiz you, take the lists with you on vacation, or do whatever it takes to get this information firmly planted in your head. Do not wait until the night before school begins. Recall of this information is expected to be automatic throughout the school year. Start studying now! In addition to these concepts, you will be expected to know all the information in this packet. Stoichiometry in particular should be mastered prior to beginning the AP Chemistry course. 1. The 7 diatomic molecules 2. Polyatomic Ions (including name, symbol and charge) 3. Variable Valences for Transition Metals 4. Rules for Naming Acids 5. Rules for Naming Ionic Compounds 6. Solubility Rules 7. Determining Oxidation Numbers Advanced Placement Chemistry is a college level course. You will need to be dedicated and work very hard if you are to be successful. Solubility Rules 1. All compounds containing alkali metal cations and the ammonium ion are soluble. 2. All compounds containing NO3-, ClO4-, ClO3-, and C2H3O2- anions are soluble. 3. All chlorides, bromides, and iodides are soluble except those containing Ag +, Pb2+, or Hg2+. 4. All sulfates are soluble except those containing Hg2+, Pb2+, Sr2+, Ca2+, or Ba2+. 5. All hydroxides are insoluble except compounds of the alkali metals, Ca2+, Sr2+,and Ba2+. 6. All compounds containing PO43-, S2-, CO32-, and SO32- ions are insoluble except those that also contain alkali metals or NH4+. Page 3 The 7 Diatomic Molecules When alone and uncharged, the following substances exist as diatomic molecules: hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. There are 7 and they form a 7 on the periodic table (with the exception of hydrogen). Whenever you write the formula for these diatomic molecules it should look like this: H2, N2, O2, F2, Cl2, Br2, I2. Remember to name them with just the element name. Rules for Naming an Acid When the name of the anion ends in –ide, the acid name begins with the prefix hydro-, the stem of the anion has the suffix –ic and it is followed by the word acid. -ide becomes hydro _____ic Acid Cl- is the Chloride ion so HCl = hydrochloric acid When the anion name ends in –ite, the acid name is the stem of the anion with the suffix –ous, followed by the word acid. -ite becomes ______ous Acid ClO2- is the Chlorite ion so HClO2 = Chlorous acid. When the anion name ends in –ate, the acid name is the stem of the anion with the suffix –ic, followed by the word acid. -ate becomes ______ic Acid ClO3- is the Chlorate ion so HClO3 = Chloric acid. Rules for Naming Ionic Compounds 1. Balance Charges (charges should equal zero) 2. Cation is always written first (in name and in formula) 3. Change the ending of the anion to –ide 4. Roman Numerals are used to identify the charge of the transition metal Rules for Determining Oxidation Number (this may be the one thing you did not learn in regular chemistry, but it’s very similar to charges, so it should be easy for you) Oxidation Number: A number assigned to an atom in a molecular compound or molecular ion that indicates the general distribution of electrons among the bonded atoms. (these are a lot like charges, except they are assigned to covalent compounds in addition to ionic compounds. They just indicate the relative attractions for electrons. 1. The oxidation number of any uncombined element is O. 2. The oxidation number of a monatomic ion equal the charge on the ion. 3. The more electronegative element in a binary compound is assigned the number equal to the charge it would have if it were an ion. 4. The oxidation number of fluorine in a compound is always –1 5. Oxygen has an oxidation number of –2 unless it is combined with F, when it is +2, or it is in a peroxide, when it is –1. Page 4 6. The oxidation state of hydrogen in most of its compounds is+1 unless it combined with a metal, in which case it is –1. 7. In compounds, the elements of groups 1 and 2 as well as aluminum have oxidation number of +1, +2, and +3, respectively 8. The sum of the oxidation numbers of all atoms in a neutral compound is O. 9. The sum of the oxidation number of all atoms in a polyatomic ion equals the charge of the ion. Variable Valences For Transition Metals Name Symbol Chromium Cr Manganese Mn Charge Stock Name +2 +3 Chromium (II) Chromium (III) +2 +3 Manganese (II) Manganese (III) +2 +3 Iron (II) Iron (III) +2 +3 Cobalt (II) Cobalt (III) +1 +2 Copper (I) Copper (II) +2 +4 Lead (II) Lead (IV) +1 +2 Mercury (I) (this is an odd one. It’s actually Hg22+) Mercury (II) +2 +4 Tin (II) Tin (IV) +1 +3 Gold (I) Gold (III) +1 +2(rarely) Silver (doesn’t need a roman numeral because it is almost always 1+) Silver (II) +3 +5 Bismuth (III) Bismuth (V) +3 +5 Antimony (III) Antimony (V) Iron Fe Cobalt Co Copper Cu Lead Pb Mercury Hg Tin Sn Gold Au Silver Ag Bismuth Bi Antimony Sb Cadmium Cd +2 Cadmium (no roman numeral needed because charge doesn’t change) Zinc Zn +2 Zinc (no roman numeral needed because charge doesn’t change) Page 5 Polyatomic Ions – Make Flashcards!! Name ammonium acetate bromate chlorate chlorite cyanide dihydrogen phosphate hypochlorite hydrogencarbonate(bicarbonate) hydrogen sulfate (bisulfate) hydrogen sulfite (bisulfite) hydroxide iodate nitrate nitrite perchlorate permanganate thiocyanate carbonate chromate dichromate oxalate selenate silicate sulfate sulfite phosphate phosphite Symbol NH4 C2H3O2 BrO3 ClO3 ClO2 CN H2PO4 ClO HCO3 HSO4 HSO3 OH IO3 NO3 NO2 ClO4 MnO4 SCN CO3 CrO4 Cr2O7 C2O4 SeO4 SiO3 SO4 SO3 PO4 PO3 Charge +1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -2 -2 -2 -2 -2 -2 -2 -2 -3 -3 Scientific (Exponential) Notation 1. Go to this website for the basics on scientific notation: http://www.wwnorton.com/college/chemistry/gilbert/tutorials/interface.asp?chapter=chapter_01&folder =scientific_notation . Make sure you take notes below. 2. Go to this website for information on addition, subtraction, multiplication, and division using scientific notation. http://www.sparknotes.com/math/algebra1/scientificnotation/section1.html a. Take notes below. b. Look to the left corner of the screen to find rules for multiplication and division. Click on this. c. Go to problems in the upper left corner of the screen. You will find practice problems and answers. Please write these on your own paper and attach them to this packet. 3. Go to this website for extra practice if desired: http://janus.astro.umd.edu/astro/scinote/ Page 6 Scientific Notation Notes: - Describe how to put numbers into scientific notation. - Describe how to take numbers in scientific notation and write them in regular notation - Describe how to add and subtract numbers in scientific notation. (you will be required to do this without a calculator in AP Chemistry, so it is essential you remember how!) - Describe how to multiply and divide numbers in scientific notation. (you will be required to do this without a calculator as well, so make sure you remember how!) Significant Figures: You are expected to memorize the rules for determining significant figures and use those rules on every assignment, test, quiz, and lab report. You will be required to use the rules for significant figures on the AP exam. 1. Go to this website: http://www.chem.sc.edu/faculty/morgan/resources/sigfigs/index.html 2. Fill out the notes from the website below. 3. Complete the practice on the website. Print out the page. Complete the problems, then check your work. Attach your work to this packet. 4. Go to this website and take the quiz: http://antoine.frostburg.edu/chem/senese/101/measurement/sigfigquiz.shtml . Be sure that you understand why the answers are correct. 5. Go to this site for practice if needed: http://www.lon-capa.org/~mmp/applist/sigfig/sig.htm or this site: http://science.widener.edu/svb/tutorial/sigfigures.html Significant figures notes: - Explain the concept of significant figures: Every number that is measured plus 1 that is estimated. Whenever you are using a measuring device, you should record your measurement so that the last number is estimated. For examples please go to this site: http://student.ccbcmd.edu/~cyau1/WhatMeaningBehindSigFig.htm - - Define the rules for deciding the number of significant figures in a measurement. To help define the ambiguity of rule 5, we will also use the following guidelines: o 10 cm has only 1 significant figure o 10. cm has 2 significant figures. The decimal point indicates the zero was significant. o We will usually use scientific notation to avoid confusion about significant figures. What is an exact number? What are the rules for determining the number of significant figures in the following types of mathematical calculations? o Addition and subtraction o Multiplication and Division - Explain the rules for rounding numbers - How do you use significant figures when using a calculator? Page 7 Density Density is the mass of a substance per unit volume of the substance. Density = Mass/ volume The density of an object can be determined through the water displacement method. The object is massed then submerged in a measured amount of water in a graduated cylinder. The final volume in the graduated cylinder is read. The volume of water displaced by the object is the volume of the object. Solve the following problems using correct significant figures: 1. A sample containing 33.42 g of metal pellets is poured into a graduated cylinder containing 12.7 mL of water, causing the water level in the cylinder to rise to 21.6 mL. Calculate the density of the metal. 2. The density of a piece of metal can be determined from mass and water displacement data. A piece of metal with a mass of 15.54 g is placed in a flask with a volume of 50.00 cm3. It is found that 40.54 g of water (d = 0.9971 g/cm3) is needed to fill the flask with the metal in it. What is the density of the metal? 3. The density of copper is 8.96 g/cm3. What is the mass of 18.88 cm3 of pure copper? 4. Describe how you might determine experimentally the density of a solid, such as a sugar cube, which is water soluble. Indicate what equipment you might use in the process. Precision vs. Accuracy Accuracy refers to the agreement of a particular value with a true value Precision refers to the degree of agreement among several measurements of the same quantity. The degree of precision refers to the number of digits that a measuring device permits one to measure. In a measuring device, all except the last digit, which is estimated, are certain. For example, a balance which measures to the nearest 0.0001 g is more precise that one that measures to the nearest 0.01 g. Percent error = Experimental value = actual value x 100% Actual value Types of error: Random error (indeterminate error) means that a measurement has an equal probability of being high or low. Systematic error (determinate error) occurs in the same direction each time; it is either always high or always low. For example: A balance could have a defect that caused it to read 1.000 g too high every time. A thermometer could have a defect that cased it to read 1.00 degrees C too low every time. 1. Would using the same balance every time in an experiment be important? Why or why not? 2. In an experiment, the density of aluminum is to be determined. Two students perform the experiment 3 times and obtain the following results: Trial Student A Student B 1 2.45 g/mL 2.68 g/mL 2 2.43 g/mL 2.70 g/mL 3 2.44 g/mL 2.71 g/mL0 a. Describe the accuracy and precision of each student’s results. For student A, calculate the mean and the percent error if the actual value is 2.70 g/mL. Temperature: Remember that science uses temperature in Kelvin almost exclusively. The Kelvin temperature scale is used because it does not have any negative numbers and the position of 0 K matches the motion of no particle motion. Temperature is a measure of the average kinetic energy (energy of motion) of a substance. When kinetic energy is zero, temperature is as low as it can possibly go. This is why the Kelvin temperature scale makes sense. At zero Kelvin particle motion stops. To convert from Celsius to Kelvin: K = oC + 273.15 Page 8 Classification of Matter Matter commonly exists in 3 states: solid, liquid, and gas. (plasma also exists, but since we are discussing earth chemistry, we will ignore it). Throughout this course, you will need to be thinking in terms of particle motion and particle attraction. These two factors should be the first you think of when considering most problems throughout the year. State of matter Shape Volume Particle Motion Solid Definite Indefinite Slow- vibrate in place Liquid Indefinite Definite Particles can move past each other but are moving slow enough to experience some attraction. Gas Indefinite Indefinite Particles moving very fast. They move so fast that particles cannot be impacted by attractions Particle attractions Strongest attractions of the 3 states OR particles are moving slow enough that they cannot overcome attractions Particles are attracted to each other but can overcome the attraction to move past each other. They cannot overcome the attractions enough to escape the liquid entirely Particle attractions are irrelevant until there is a high pressure or low temperature. Page 9 Identify the following as substance or mixture, then identify mixtures as heterogeneous or homogeneous AND identify substances as elements or compounds. 1. Carbon 2. salt water 3. sand in water 4. H2O 5. NaCl 6. Cl2 7. Cu 8. Silver 9. CuSO4 Physical versus Chemical Changes Physical changes- changes that do not change the original composition of the substance. Changes in state such as boiling or melting are physical changes. Changes involving an alteration in the form of the substance such as grinding or tearing are physical changes. Bonds are not broken and no reaction occurs. Physical properties- properties that can be observed without changing the composition of the substance. Examples: Density, color, and boiling point. Chemical changes- change the composition of the original substance by breaking and making bonds between atoms A new substance is produced when a chemical change occurs. Evidence a chemical change has occurred includes: Change in color, change in odor, production of gas or solid (precipitate), change in energy. These indications do not always mean a chemical change has occurred, but they often do. Examples of chemical properties include: flammability and reactivity to air. History of the atom and atomic structure: 1. Go to this website: http://www.neoam.cc.ok.us/~rjones/Pages/online1014/chemistry/chapter_8/pages/history_of_atom.html 2. Read about the history of the atom. Pay special attention to the people and experiments involved in finding the electron, proton, neutron, and nucleus. In addition, pay special attention to the periodic table developments. 3. Study the history of the atom. You may wish to take some notes from this site. 4. Make sure you know what protons, neutrons, and electrons are. Make sure you know what ions and isotopes are. You can check out this website: http://web.jjay.cuny.edu/~acarpi/NSC/3-atoms.htm if you forgot. 5. Remember that the atomic number indicates the number of protons in an element. This is the subatomic particle that identifies the element. 6. Electrons are equal to protons if the charge of the atom is zero. 7. A negative charge means that additional electrons were gained by the atom. 8. A positive charge means that electrons were lost by the atom. 9. neutrons = mass number – atomic number 10. Remember that the symbol for an element is often written like this: Page 10 Practice finding electrons, protons, and neutrons: Element Symbol Mass number Atomic name number Carbon 14 6 # of protons # of neutrons # of electrons C Fluorine Magnesium 8 35 18 Naming Compounds and Writing Formulas In AP Chemistry, you will be expected to name compounds and write formulas accurately for almost every problem that is done the entire year. You are expected to have the rules memorized and will not be given the use of a cheat sheet or flow chart for any test or quiz. *The first step in any naming or formula situation is to identify whether you have an acid, ionic compound, or covalent compound. For now follow these rules: Ionic- contains metal and nonmetal or polyatomic ions Covalent- contains 2 nonmetals or metalloid and nonmetal Acid- starts with H (except for water) *For ionic compounds, you should have most of the common polyatomic ions memorized. You’ll need to know formula, charge, and name of each ion. I’ve attached a sheet of these for you to study. *For covalent compounds, you will need to memorize the first 10 prefixes. 1. Go to this website: http://ea008.k12.sd.us/Chemistry%20PP/chemistry_powerpoints.htm Click on the PowerPoints for Ionic naming and Acid naming, Ionic formulas, and acid formulas, and covalent naming and formulas. Take notes below. 2. Go to this website to practice both ionic and covalent naming http://chemistry.csudh.edu/lechelpcs/namingcsn7.html 3. Go to this website: http://misterguch.brinkster.net/pra_namingwkshts.html Click on Naming acids and bases worksheet. Print it out. Complete the worksheet. Check your work. Attach the worksheet. 4. check out this site for basic information about polyatomic ions: http://antoine.frostburg.edu/chem/senese/101/compounds/polyatomic.shtml 5. For practice writing formulas: complete the following (keep in mind that covalently bonded substances are referred to as molecular). - Describe naming of ionic compounds - Describe writing ionic formulas - Describe naming of acids - Describe writing acid formulas Page 11 - Describe naming covalent compounds - Describe writing covalent formulas - Notes on polyatomic ions In the following chart, write the proper chemical formula for each of the compounds. Identify each compound as molecular (M), ionic (I), or acidic (A) Number Name Type of compound Formula 1 Calcium Oxide 2 Phosphorus Pentaiodide 3 Sulfuric Acid 4 Ammonium Perchlorate 5 Barium Hydroxide 6 Molybdenum (II) iodide 7 Aluminum Phosphate 8 Lithium Fluoride 9 Titanium (IV) sulfide 10 Chloric Acid 11 Sodium Peroxide 12 Chromium (III) sulfite 13 Diphosphorus Pentoxide 14 Cobalt (II) chlorite 15 Strontium Permanganate 16 Silver Chromate 17 Carbon Tetrachloride 18 Magnesium nitrite 19 Zinc Oxide 20 Nitrous Acid 21 Potassium Carbonate 22 Lead (IV) nitride 23 Hydrofluoric acid 24 Rubidium nitrate 25 Silicon Dioxide 26 Hydrosulfuric acid 27 Phosphoric acid 28 Sulfurous acid Balancing equations: A balanced chemical equation is one that has the same number of atoms on both sides of the equation. Remember that this must be true due to the law of conservation of mass. Every equation you use this year MUST be balanced! 1. Go to this website: http://funbasedlearning.com/chemistry/chembalancer/default.htm OR this website: http://funbasedlearning.com/chemistry/chemBalancer3/default.htm (the first is the easy version. The second is the harder version. I recommend going to the second. You may turn in a worksheet for either version) 2. Scroll down the page until you see a link called: this worksheet. Click on the worksheet. Fill out the worksheet as you complete the activity. Attach the worksheet. Page 12 3. If you feel you need more information you may wish to check out one of these sites: http://www.chemistry.ohio-state.edu/betha/nealChemBal/ http://richardbowles.tripod.com/chemistry/balance.htm Chemistry Conversions 1. Refresh your memory regarding moles, Avogadro’s number, molar mass, and molar volume by reading over this website: http://www.cdli.ca/sampleResources/chem2202/unit01_org01_ilo03/b_activity.html 2. Complete the Exercises 1, 2, and 3. Check your work. Attach your work. 3. Perform the practice problems below and check your work using the attached answer key. Notes- Chemistry Conversions What is a mole? (please remember that particles can include ions, atoms, molecules, or formula units. Remember a formula unit is ionic. A molecule is covalent. If a formula unit is broken down it consists of ions. If a molecule is broken down it consists of atoms.) What is molar mass? What is molar volume? Practice Problems for chemistry Conversions (make sure you show your work- including units and formula of the chemical. Make sure you answer using significant figures) 1. How many molecules are in 5.6 moles of water? 2. How many atoms are in 5.6 moles of water? 3. How many moles of NaCl are present if you have 5.1 x 1026 formula units of NaCl? 4. How many moles of Cl- are present if you have 7.6 x 1028 formula units of BaCl2? 5. How many grams of (NH4)2SO4 are needed to make a solution using 2.00 moles of (NH4)2SO4? 6. How many liters of hydrogen gas at STP are present if 6.5 moles of hydrogen gas are present? 7. How many atoms of hydrogen are there in 4 L of hydrogen gas at STP? Stoichiometry: Make sure you can do Stoichiometry conversions. You will need to be able to perform all types of conversions without referring to any flow charts or guides. However, if you need help getting started, use the chart below. **the conversion to liters is not shown on the chart above. Remember that if a gas is at STP, there are 22.4 L in 1 mole of gas. Page 13 You will need to find the limiting reagent if you are given 2 reactants. Remember that the limiting reagent is used up first and the excess reagent is left over at the end. BCA tables enable you to easily identify the limiting reactant, excess reactant, and quantities of product. REMEMBER to use MOLES in your table. Finding empirical formula (remember that empirical formula is the lowest whole number ratio of elements in a compound) 1. If you are given a percent, then change the % to a g. If you are given grams, start at #2. If you are given moles, start at #3. 2. Convert from grams to moles using molar mass 3. Divide all numbers of moles by the smallest number of moles to get the ratio of moles of each element. 4. If the numbers are whole numbers, use them as subscripts when you write your formula 5. If the number are not whole numbers, multiply all numbers by an appropriate integer to obtain whole numbers. Then use the new, whole numbers as subscripts when you write the formula Finding molecular formula. (remember that molecular formula includes every element actually present in the compound.) 1. Find empirical formula if is was not given already 2. Find the molar mass of the empirical formula 3. Divide the molar mass of the molecular formula by the molar mass of the empirical formula 4. Multiply the subscripts of the empirical formula by the number obtained in number 3. 5. Write your new formula. Stoichiometry Practice: 1) If a total of 9 mol of NaHCO and 6 mol of C H O react, how many moles of Na C H O will be produced? 3NaHCO (aq) + C H O (aq) 3CO (g) + 3H O(s) +Na C H O (aq) 2) How many grams of CO are needed to react with an excess of Fe O to produce 8.5 g Fe? Fe O (s) + 3CO(g) 3CO (g) + 2Fe(s) 3) How many liters of O are needed to react completely with 89 L of H S at STP? 2H S(g) + 3O (g) 2SO (g) + 2H O(g) 4) For the reaction 2Na(s) + Cl (g) 2NaCl(s), how many grams of NaCl could be produced from 5.5 g of Na and 2.0 L of Cl (at STP)? 5) Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrogen gas are formed when 54g of sodium are added to water? 2Na + 2H O 2NaOH + H 6)Consider the following reaction: 2H S(g) + 3O (g) 2SO (g) + 2H O(g) If you have 4 mol of H S reacting with excess oxygen, and the actual yield is 64.08g of water, what is the percent yield of the reaction? 7)What is the limiting reagent when 224 g of nitrogen react with 60.6 g of hydrogen? N (g) + 3H (g) 2NH (g) 8) This equation shows the formation of aluminum oxide: 4Al(s) + 3O2 2O3(s) How many moles of aluminum are needed to form 7.8 moles of aluminum oxide? 9) How many formula units of KCl are produced by the decomposition of 4.5 x 1025 formula units of KClO3? 2KClO3 2(g) 10) The equation for the combustion of carbon monoxide is: 2CO(g) + O2 2 (g) How many liters of CO are required to react completely with 54 grams of O2? Page 14 11)How many formula units of AgNO3 are needed to react completely with 5.74 moles of Cu? The equation is: 2 AgNO3 3)2 + 2 Al 12) If 45.5 g of H are reacted with excess CO, how many grams of CH OH are produced, based on a yield of 98%? CO(g) + 2H (g) CH OH(l) 13) What is the empirical formula of a compound that is 40% sulfur and 60% oxygen by weight? 14) Calculate the molecular formula of the compound with the following empirical formula and molar mass: C H , 58 g/mol. Name: Hour: AP CHEMISTRY- Extra Credit PORTION OF THE SUMMER ASSIGNMENT Scientific Notation: Write the following numbers in correct scientific notation: 1) 0.000 000 00076 2) 17 000 000 000 000 3) 0.457 4) 1500 5) 3100 x 102 6) 300 x 10-4 Write the following numbers in correct regular (decimal) notation: 7) 5.6 x 105 8) 4.3 x 10-4 9) 1.2 x 103 10) 1.2 x 10-2 11) 15.76 x 10-3 12) 0.098 x 105 Perform the following calculations without the use of a calculator. Write your answers in correct scientific notation: 13) 5.4 x 105 + 5.4 x 107 = 14) 4.3 x 104 – 1.2 x 105 = 15) 6.7 x 1023 x 2.0 x 1043 = 16) 8.7 x 1054 / 1.2 x 1032 = Significant figures: How many significant figures are in each of the following? 1) 1.00 cm 2) 0.000 0045 m 3) 0.000 00450 m 4) 10 m 5) 10. m 6) 15 people Perform the following calculations. Remember to answer using correct significant figures: 7) 5.432cm + 3.2 cm = 8) 8.857 cm – 1.12 cm = 9) 8.9 cm x 2 cm = 10) 888 cm2 / 2.0 cm = Page 15 Perform the following calculations without a calculator. Use your knowledge of BOTH scientific notation AND significant figures. 11) 5.43 x 103 + 5.54 x 105 = 12) 3.2 x 105 – 1.22 x 104 = 13) (4.2 x 1010)(2 x 102) = 14) (8.8 x 1020) / (4 x 1010) = Naming and writing formulas: For this section, write from memory the formula and charge for each polyatomic ion indicated: 1) Sulfate 2) Sulfite 3) Nitrate 4) Nitrite 5) Phosphate 6) Phosphate 7) Cyanide 8) Peroxide 9) Hydroxide 10) Chlorate 11) Chlorite 12) Perchlorate (per means 1 more oxygen than the regular –ate) 13) Hypochlorite (hypo- means 1 less oxygen than the regular – ite) 14) Chromate 15) Carbonate 16) Dichromate 17) Bicarbonate (or hydrogen carbonate) (bi means add a hydrogen ion) 18) Oxalate 19) Permanganate 20) Thiosulfate (Thio means: replace one of the oxygen atoms with a sulfur atom) Indicate the type of compound: Molecular, Ionic, or Acid. Then name the compound. Formula Type of Compound Name 21) CF4 22) KI 23) SF6 24) CaCl2 25) CuCl 26) CuCl2 27) BaO 28) SiO2 29) AlCl3 30) FeSO4 31) Fe2(SO4)3 32) H2CO3 33) HF 34) PbO 35) H2S 36) SnO2 37) H3PO4 38) H3PO3 39) Ba(OH)2 Page 16 Indicate the type of compound: Molecular, Ionic, or Acid. Then write the formula of the compound Name Type of compound Formula 40) Copper (II) carbonate 41) Calcium hydroxide 42) Silicon dioxide 43) hydrochloric acid 44) hydroiodic acid 45) barium phosphate 46) carbon monoxide 47) potassium chloride 48) dinitrogen tetroxide 49) phosphorous acid 50) hydrosulfuric acid Balancing Equations Balance the equations below: 1) Na + Cl2 NaCl 2) Rb + S8 Rb2S 3) H3PO4 + Ca(OH)2 Ca3(PO4)2 + 4) NH3 + HCl NH4Cl 5) Li + H2O LiOH + H2 6) NH3 + O2 N2 + H2O 7) FeS2 + O2 Fe2O3 + SO2 8) C+ SO2 CS2 + CO 9) C6H6 + O2 CO2 + H2O 10) C10H22 + O2 CO2 + H2O 11) Ca3(PO4)2 + SiO2 + C CaSiO3 + H2O CO + P Write and balance the following equations: 12) iron + sulfur iron(II) sulfide 13) zinc + copper(II) sulfate zinc sulfate + copper 14) silver nitrate + sodium bromide sodium nitrate + silver bromide 15) potassium chlorate (heated) potassium chloride + oxygen 16) mercury(II) oxide (heated) mercury +oxygen 17) potassium iodide + lead(II) nitrate lead(II) iodide + potassium nitrate 18) aluminum + oxygen aluminum oxide 19) iron(III) chloride + ammonium hydroxide iron (III) hydroxide + ammonium chloride ______ Page 17 Precision vs. Accuracy: 1) Balance A measures to the tenths position. Balance B measures to the hundredths position. Balance B is more than balance A. 2) Describe the precision and accuracy of the following students: (the true value is 3.5 g) Student A: 3.5 g, 3.4 g, 3.6 g. Student B. 5.7 g, 8.7 g, 1.2 g 3) Calculate the percent error of the following experiment. You have determined that the density of Aluminum is 2.77 g/mL. The true value of the density of Al is 2.70 g/mL. Classifications of matter: For each of the following, describe the motion and interaction at a particle level: 1. Solid 2. Liquid 3. Gas Answer the following questions 4. Two clear solutions combine to form a yellow precipitate and a clear solution. Was this a chemical or physical change? Explain. 5. Identify each of the following as substances or mixtures. For each substance, identify elements vs Compounds. For each mixture, identify heterogeneous vs. homogeneous. a. Cu b. Zn c. H2O d. Sugar water e. Dirt in water Chemistry Conversions and Stoichiometry- You must show all work, include units and formulas, and box or highlight your answers for this section. Be sure to answer using significant figures. 1. How many formula units are in 4.5 moles of NaCl? 2. How many ions are in 4.5 moles of NaCl? 3. How many moles of H2 are present if you have 8.1 x 1026 molecules of H2? Page 18 4. How many moles of Cl- are present if you have 4.7 x 1027 formula units of AlCl3 ? 5. How many grams of (NH4)3PO4 are needed to make a solution using 2.00 moles of (NH4)3PO4? 6. How many liters of oxygen gas at STP are present if 7.4 moles of oxygen gas are present? 7. How many atoms of chlorine are there in 4.00 L of chlorine gas at STP? 8. How many grams of CO are needed to react with an excess of Fe O to produce 4.25 g Fe? Fe O (s) + 3CO(g) 3CO (g) + 2Fe(s) 9. How many liters of O are needed to react completely with 45 L of H S at STP? 2H S(g) + 3O (g) 2SO (g) + 2H O(g) 10. For the reaction 2Na(s) + Cl (g) 2.5 L of Cl (at STP)? 2NaCl(s), how many grams of NaCl could be produced from 4.5 g of Na and 11. Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrogen gas are formed when 87g of sodium are added to water? 2Na + 2H O 2NaOH + H 12. Consider the following reaction: 2H S(g) + 3O (g) 2SO (g) + 2H O(g) If you have 8 mol of H S reacting with excess oxygen, and the actual yield is 128.16 g of water, what is the percent yield of the reaction? 13. The equation for the combustion of carbon monoxide is: Page 19 2CO(g) + O2(g) 2 CO2 (g) How many liters of CO are required to react completely with 8.7 grams of O2? 14. How many formula units of AgNO3 are needed to react completely with 7.9 moles of Cu? The equation is: 2 AgNO3 + Cu Cu(NO3)2 + 2 Al 15. If 85.7 g of H are reacted with excess CO, how many grams of CH OH are produced, based on a yield of 98%? CO(g) + 2H (g) CH OH(l) 16. What is the empirical formula of the compound that is 42.10 % carbon, 5.26 % hydrogen, 24.56 % nitrogen, and 28.07 % oxygen? If molecular mass of the compound is found to be 171.2 g/mol what is it's molecular formula? Atomic Structure: 1. How was the nucleus discovered? 2. How was the electron discovered? 3. How was the proton discovered? 4. How was the neutron discovered? 5. Fill out the following chart: Element name Iodine Symbol 14 7 Mass number Atomic number # of protons Page 20 # of neutrons # of electrons N Aluminum 28 14 5 7 8 Density - Answers: 1. 3.8 g/mL 2. 1.66 g/cm3 The volume of water displaced by the piece of metal is 50.00 cm3 – 40.66 cm3 = 9.34 cm3. Using mass/ volume = 15.54 g / 9.34 cm3 = 1.66 g/cm3. Not that 40.54 g of water with density of 0.9971 g/cm3 has a volume of 40.66 cm3. 3. 169 g. From density = m/v, solving for mass and using mass = d x v = 8.96 g/cm3 x 18.88 cm3. You could also estimate for a multiple choice problem and using 9 x 20 to get an answer of about 180 g. This would make a multiple choice problem go faster! 4. There are 2 methods. First: Since density is a ratio of the mass of the object compared to the volume of the object, you might first determine the mass of the sugar cube using a balance. Greater precision is possible with an analytical balance. Then determine the volume of this regular cube by measuring its length, with, and depth. Then calculate the volume. V = l x w x d = side 3 Then just divide mass by the volume. Second method: Use liquid displacement to find volume. However, the liquid used may not be water because the object is soluble in water. Select a nonpolar liquid to keep the polar solid from dissolving. Perhaps 1,1,1-trichloroethane. Use a balance to find the mass. Divide mass by volume. Types of Error - Answers. 1. Using the same balance is important because it may have some error. If you use the same balance every time, the error will be systematic error, which is unlikely to matter in some experiments because many times we will be measuring the difference between 2 masses. If you used 2 different balances, the error may be magnified if both balances have systematic errors in different directions. 2. Student A was precise but inaccurate. Student B was precise and accurate. Classification of Matter - Answers: 1. substance- element 2. mixture- homogeneous 3. mixture- heterogeneous 4. substance- compound 5. Substance- compound 6. Substance- element 7. Substance- element 8. Substance- element 9. Substance- compound Practice finding electrons, protons, and neutrons - Answers: Element name Carbon Carbon-14 (less common isotope of C) Fluorine Magnesium Oxygen Chlorine Symbol 12 6 14 6 19 9 24 12 16 8 35 17 C C F Mg O Cl # of protons 12 Atomic number 6 Page 21 # of neutrons # of electrons 6 6 6 14 6 6 8 6 19 9 9 10 9 24 12 12 12 12 16 8 8 8 8 35 17 17 18 17 Mass number Formula practice – Answers: Number Name 1 Calcium oxide 2 Phosphorus Pentaiodide 3 Sulfuric Acid 4 Ammonium Perchlorate 5 Barium Hydroxide 6 Molybdenum (II) iodide 7 Aluminum Phosphate 8 Lithium Fluoride 9 Titanium (IV) sulfide 10 Chloric Acid 11 Sodium Peroxide 12 Chromium (III) sulfite 13 Diphosphorus Pentoxide 14 Cobalt (II) chlorite 15 Strontium Permanganate 16 Silver Chromate 17 Carbon Tetrachloride 18 Magnesium nitrite 19 Zinc Oxide 20 Nitrous Acid 21 Potassium Carbonate 22 Lead (IV) nitride 23 Hydrofluoric acid 24 Rubidium nitrate 25 Silicon Dioxide 26 Hydrosulfuric acid 27 Phosphoric acid 28 Sulfurous acid Type of compound I M A I I I I I I A I I M I I I M I I A I I A I M A A A Formula CaO PI5 H2SO4 NH4ClO4 Ba(OH)2 MoI2 AlPO4 LiF TiS2 HClO3 Na2O2 Cr2(SO3)3 P2O5 Co(ClO2)2 Sr(MnO4)2 Ag2CrO4 CCl4 Mg(NO3)2 ZnO HNO2 K2CO3 Pb3N4 HF Rb(NO3)2 SiO2 H2 S H3PO4 H2SO3 Page 22 Chemistry Conversions – Answers to practice problems for chemistry conversions: (remember that definitions and definite numbers have infinite significant figures, so the only significant figures you need to worry about are the ones in the beginning number) 1)(5.6 mol H2O)(6.022 x 1023 molecules of H2O) = 3.4 x 1024 molecules of H2O 1 mol H2O 23 2) (5.6 mol H2O)(6.022 x 10 molecules of H2O)(3 atoms of H and O) = 1.0 x 1025 atoms of H and O 1 mol H2O 1 molecule H2O 26 3) (5.1 x 10 formula units NaCl)(1 mol NaCl ) = 8.5 x 102 moles NaCl or 850 moles 23 6.022 x 10 formula units NaCl 28 4) (7.6 x 10 formula unitsBaCl2)(1 mol BaCl2 )(2 mol Cl) = 2.5 x 105 mol Cl23 6.022 x 10 formula units BaCl2 1 mol BaCl2 5) (2.00 mol (NH4)2SO4)(132.17 g (NH4)2SO4) = 264.34 g (NH4)2SO4 = 264 g (NH4)2SO4 1 mol (NH4)2SO4 6) (6.5 moles H2)(22.4 L H2) = 145.6 L H2 = 150 L H2 1 mol H2 7) (4 L H2)(1 mol H2) = 0.2 mol H2 22.4 L H2 Stoichiometry Practice - Answers: 1. (9 mol NaHCO3)(1 mol C6H8O7) = 3 mol of C6H8O7 are needed to use up all the NaHCO3. We have 3 mol NaHCO3 6 mols of C6H8O7, so NaHCO3 is the limiting reagent. (9 mol NaHCO3)(1 mol Na3C6H5O7) = 3 mol Na3C6H5O7 3 mol NaHCO3 2. Fe O (s) + 3CO(g) 3CO (g) + 2Fe(s) (8.5 g Fe) (1 mol Fe) (3 mol CO) (28.01 g CO) = 6.4 g CO 55.85 g Fe 2 mol Fe 1 mol CO 3. 2H S(g) + 3O (g) 2SO (g) + 2H O(g) (89 L H2S) (1 mol H2S) (3 mol O2 ) (22.4 L O2) = 133.5 L O2 22.4 L H2S 2 mol H2S 1 mol O2 4. 2Na(s) + Cl (g) 2NaCl(s) (5.5 g Na)(1 mol Na) (1 mol Cl2)(22.4 L Cl2) = 2.7 L Cl2 needed to use up all the Na. We have 2.0 L Cl2, so Cl2 22.99 g Na 2 mol Na 1 mol Cl2 is the limiting reagent. (2.0 L Cl2)(1 mol Cl2)(2 mol NaCl) (58.44 g NaCl) =10. g NaCl 22.4 L Cl2 1 mol Cl2 1 mol NaCl 5. (54 g Na)(1 mol Na )(1 mol H2 )(6.022 x 1023 cules H2) = 7.1 x 1023 cules H2 22.99 g Na 2 mol Na 1 mol H2 6. (4 mol H2S)(2 mol H2O)(18.02 g H2O) = 72.08 g H2O – Theoretical Yield 2 mol H2S 1 mol H2O 64.08 g H2O = 89 % yield of H2O 72.08 g H2O 7. (224 g N2)(1 mol N2 ) (3 mol H2) (2.02 g H2) = 48.4 g H2 are needed to use up all the N2. We have 28.02 g N2 1 mol N2 1 mol H2 60.6 g of H2, so N2 is the limiting reagent. 8. 4Al(s) + 3O2(g) 2Al2O3(s) (7.8 mol Al2O3)(4 mol Al ) = 15.6 mol Al 2 mol Al2O3 9. 2KClO3(s) 2KCl (s) + 3O2(g) ( 4.5 x 1025 formula units of KClO3)(1 mol KClO3 )(2 mol KCl ) (6.022 x 1023 f.u. KCl) = 6.022 x 1023 f.u. KClO3 2 mol KClO3 1 mol KCl 25 4.5 x 10 f.u. KCl 10. 2CO(g) + O2(g) 2 CO2 (g) Page 23 (54 g O2) (1 mol O2 )(2 mol CO) (22.4 L CO) = 76 L CO 32.00 g O2 1 mol O2 1 mol CO 11. 2 AgNO3 + Cu Cu(NO3)2 + 2 Al (5.74 moles of Cu) (2 mol AgNO3)(6.022 x 1023 f.u. AgNO3) = 6.91 x 1024 f.u. AgNO3 1 mol Cu 1 mol AgNO3 12. (45.5 g of H2) (1 mol H2 )(1 mol CH3OH) (32.05 g CH3OH) = 361 g CH3OH 2.02 g H2 2 mol H2 1 mol CH3OH 361 g CH3OH x .98 = 353.7 g CH3OH 13. 40% sulfur and 60% oxygen 40 g S(1 mol S ) = 1.247 mol S (60g O)( 1mol O ) = 3.75 mol O 32.07 g S 16.00 g O Divide by the smallest number of moles: S: 1.247 mol = 1 O: 3.75 mol O = 3 1.247 mol 1.247 mol Formula SO3 14) C2H5 58 g/mol Molar mass of empirical: (2)(12.01g/mol) + (5)(1.01 g/mol) = 29.07 g/mol Divide molar mass of molecular formula by molar mass of empirical: 58 g/mol 29.07 g/mol C4H10 = 2 Multiply the subscripts of the empirical formula by 2 to get the molecular formula