SECOND NINE WEEKS NOTES PACKET COLLIER CHEMISTRY PRE-AP 1 2 UNIT 5 CHEMICAL NAMING & BALANCING Chapter 6, 15.1, 16.1 3 NOMENCLATURE: Atoms of _______________ elements combine to form _________________ that are represented by ________________________________. All compounds can be _________________ in such a way that others can understand the make-up of the compound. Chemical formulas are represented by using the ______________ symbols with ________________ that show the number of each element in a given compound 4 Chemical Bonding Molecules – the smallest electrically neutral unit of a substance. 1. _________________ are the building blocks of substances. 2. Atoms of most elements will _______________________ different compounds (except ____________________) 3. Molecules are made up of ______________________ that act as one unit. Ex: 4. Molecular compounds can be called _________________ or ______________________ molecules. 5. Molecular Compounds are composed of molecules that are ___________________________________________. 5 Ions & Ionic Compounds 1. ___________ are atoms or a group of atoms that have ____________________________________ 2. A loss of electrons gives the atom a positive charge; therefore a gain of an electron would give the atom a negative charge. 3. Atoms of ___________________ elements tend to ___________ electrons to become ______________ and ________________ tend to _________________ electrons to become ____________________. (+) ions also called _____________. Ex: (-) ions = ________________. Ex: 4. Ionic compounds consist of a _______________ bonded to a ____________. The charge of the compound is ___________________. 6 OXIDATION NUMBER This is a ______________ or _______________ number assigned to an atom according to a set of rules The oxidation number of a ___________________ ion is equal to its ionic charge Ex. Br- = _______ Mg +2 = __________ The oxidation number of ____________ in a compound is _________ except in a metal hydride where it is ______ The oxidation number of _____________ is ___________ except in ____________ where it is __________ The oxidation number of the atom in its _______________ form is _________ 7 Electrons in Ionic Bonding Valence Electrons -- 1. Determines the _______________ properties of an element. 2. The __________ determines the number of valence electrons 3. Electron Dot Structures – ___________________ that show only valence electrons. Octet rule -- atoms tend to achieve the ___________________ _____________________________. **Atoms will gain or lose electrons to achieve this. 8 Ionic Bonds -- the ____________ of attraction between ___________________. (____________ &__________________) Covalent Bonding -- a bond in which two atoms _________ __ a pair of electrons. (________________________) 1. Structural formula H – H 2. Sharing of electrons occur if atoms involved achieve the _________________ rule. 3. _______________ and ______________ Covalent Bonding means that more than one pair of electrons are shared. Example: 9 Chemical Compounds Chemical Formula’s -- Shows the ______________ and _______________ of atoms in a compound. - _______________ show the number of atoms. Ex: H2O • Ionic compounds consist of a ____________ ion with a ________________ ion in the lowest whole number ratio. Ex: • Molecular compounds typically consist of _____________________ covalently bonded together Ionic Charges • ________________________ ions consist of only 1 ion. • _________________ ions consist of tightly bound atoms that behave as a single unit, that has either lost or gained electrons to become (+) or (-). Ex: NO3-, SO4-2 10 Balancing Formulas Writing Formulas Ionic Compounds • Criss Cross Method 1. Write __________________ and ______________ for each ion present. Compare charges: If charges equal _________ then simply write symbols together. If charges don’t equal 0 then _____________________ and write them as a _________________. Criss-Cross Method Al+3 + O-2 → Al2O3 Examples: Sodium Chloride: Aluminum Sulfide: 11 Binary Molecular Compounds Consists of two nonmetals 1. Write the symbols of the ___________ elements, change ________________ to subscripts. Prefixes Mono = Hexa = Di = Hepta = Tri = Octa = Tetra = Nona = Penta = Deca = Acids 1. Acids consist of a ___________ bonded to an _____________ (negative ion ). Step 1: Step 2: 12 Examples: - Hydrochloric Acid - Nitric Acid - Nitrous Acid Step 3: _________________________________ for this compound as you would when writing any molecular formula. Hydro- ; -ic = -ide -ic = -ate -ous = -ite 13 14 Naming Compounds Ionic Compounds 1. Write the ___________ of the ___________ present. 2. Determine which ____________ forms the compound by looking at the ratio of the atoms and compare to the ratio of the charges. 3. Remember that the overall charge of the compound has to ________________________. 4. Example: CuO is it copper I or II? The ratio of atoms is 1:1 and the charge on O is –2 so the Cu has to be 2 to have the same ratio. The name of the compound would be ___________________ 15 Binary Molecular Compounds: 1. Write the name of the ____________ in the first position and if it has a subscript change it to a _____________. 2. Write the name of the ______________ element. Change the ending to ___________, and always use a _______________ that corresponds with the number of atoms present in the molecule. Example: PO5 = S2 N = 16 Acids **If the compound starts with an H then it considered to be an acid. Step 1: Step 2: - If the ending is __________, place ____________ in front of the negative ion name, then drop the –ide and add _________. - If the ending is ____________, drop the -ate ending and add _____________. - If the ending is ______________, drop the ending and add __________. Examples: H2S = H2SO4 = Hydro- ; -ic = -ide H2SO3 = -ic = -ate -ous = -ite 17 18 Molecular Weights 19 20 UNIT 6 Chemical Quantities--Chapter 7 Atomic Mass (Weight) The ______________ of an ______________ expressed in _______________. Examples: Carbon – Sulfur – Iron – Mass of a Mole of a Compound 1st you must _____________________________ of the compound The formula tells you ___________________ of each element that is present. Example: SO3 – 21 After you know the _________________ then you calculate the _______________ of the compound. Molar mass Find the molecular mass of each compound. 1. Li2S 2. FeCl3 3. Ca(OH)2 4. N2O5 22 Percent Composition % mass of element = Or Grams of element Grams of Compound X 100 % Comp. = Part X 100 Whole Practice Problem Ethane (C6H6) ---- 222.06 g of C6H6 mole of C = 216.00 g mole of H = 6.06 g Find the % Composition of Carbon & Hydrogen in Ethane (C6H6). 23 Significant Figures & Scientific Notation All the _______________that can be known precisely in a measurement, plus a __________________________ digit. Expression of numbers in the form ___________________ where n is equal to or greater than one and less than 10 H2O – How many much Hydrogen is in Water? What is Hydrogen’s % Composition in Water? What would happen to the % of hydrogen with 2 molecules of Water? 24 SIGNIFICANT DIGITS To determine the number of significant digits in a written number complete one of the following: 1. Qualifying statement: The numerical value has no decimal place written. Action to take: Count from the first non-zero digit to the last non-zero digit. Examples: 1. 18,004 - 5 significant digits 2. 10,040,000– 4 sig digs 3. 10 – 1 sig dig 2. Qualifying statement: The numerical value contains a decimal place. Action to take: Count from the first non-zero digit to the end of the number. Examples: 1. 100.00 – 5 sig digs 2. 1,050. – 4 sig digs 3. 0.000 145 00 – 5 sig digs 25 What is a mole? Avogadro’s number = _________________________________ Standard Temperature and Pressure (STP) – a. Standard temperature is ____________ or ____________ b. Standard pressure is _______________________________ _______________________________________________. • 1 mol of any gas at STP = ________________ 26 Representative Particle Refers to the _________________________ in a substance: usually atoms, molecules, or formula units. (ions) Example: Fe is composed of _______________ atoms. K is composed of ___________________ atoms. Example: How many moles of Mg is 1.25 x 1023 atoms of Mg? Know: Unknown: 27 Practice Problems How many moles are 2.80 x 1024 atoms of silicon? How many molecules is 0.360 moles of water? Amt. in Compounds Carbon dioxide has 3 atoms. 1-carbon 2-oxygen Thus one mole of CO2 contains three times Avogadro’s # of atoms. 28 Example: How many atoms are in 2.12 mole of propane (C3H8)? Know: Unknown: Desired conversion: 29 Practice Problems How many atoms are there in 1.14 mole SO3? How many moles are there in 4.65 x 10 24 molecules of NO2? Mole -- gram How many grams are in 3.32 mole K? How many grams are in 4.52 x 10-3 moles of C20H42? 30 Gram -- Mole How many moles are in 3.70 x 10-1 grams of Boron? How many moles are in 27.4 g TiO2? 31 32 Unit 7 Balancing Chemical Reactions & Predicting Products Ch. 8 & 19.1 33 Reactions 34 Equations An _______________________ is a description of a chemical reaction indicating the ___________________________, the _____________________ and a _____________ of their quantities. REMEMBER: __________________ → _________________ _______________ (reactants) = ___________________ (products) Coefficients -- The reaction is said to go to ______________________ when no reactants remain when the reaction has stopped. 35 The reaction may be ______________________. When this happens, a complete cycling of events exists. It is a continuous ongoing process. The Law of Conservation of Mass: in reactions atoms are neither _______________________ nor ___________________ only ______________________ The Law of Conservation of Mass __________________________________________. What is the relationship between the mass of the reactants and the mass of the products? How are chemical reactions balanced? 36 _________________ are used to separate reactants or products on the same side of the arrow. Catalyst: 2H2 + O2 → 2H2O 1. What are the reactants? 2. What are the products? 3. What are the coefficients for the whole reaction? 37 Rules for Balancing Equations: 1. Determine the ____________________ for all reactants and products. Indicate physical states in parentheses. 2. Write the formulas for the __________________ and _____________________________ of the arrow. Then separate two or more formulas with + signs. 3. __________________________________of each element for both sides of the equation. 4. ______________ the elements one at a time by using ________________. 5. Check each atom to be sure that the equation is balanced. 6. Make sure the _______________ are in the ______________________________that balances. Diatomic Elements 38 Classifying reactions Synthesis (Combination) reaction: The ____________ can be elements or compounds. The _______________ will always be a compound. A + B → AB Decomposition reactions: • The __________ is always a ______________. • Most decomposition Reactions requires energy such as light, heat or electricity. AB → A + B 39 Single replacement reactions: Single elements changes places with the other ion that is the same as the single element. ____________________ & ______________________ A + BC → AC + B Double Replacement: AB + CD → CB + AD Combustion Reactions: 40 Factors Effecting Reaction Rates: Temperature: Concentration: Catalyst: Inhibitor: Neutralization: 41 Predicting Products 1. To predict products of any reaction the first step is to ______________________________________ it is. 2. Then apply existing rules for the type of reaction it is: Activity Series of metals: an invaluable aid to predicting the products of replacement reactions. It also can be used as an aid in predicting products of some other reactions. Going from bottom to top, the metals: 42 Metal Metal Ion Reactivity Lithium Li+ Most Reactive Potassium K+ - Calcium Ca2+ - Sodium Na+ - Magnesium Mg2+ - Aluminum Al3+ - Manganese Mn2+ - Zinc Zn2+ - Chromium Cr2+,Cr3+ - Iron Fe2+,Fe3+ - Lead Pb2+ - Copper Cu2+ - Mercury Hg2+ - Silver Ag+ - Platinum Pt2+ - Gold Au+,Au3+ Least Reactive 43 Synthesis (Combination): ______________ + ___________________ → Combine the 2 elements into a compound Practice: 1. Aluminum + Oxygen → 2. Chlorine + Potassium → 3. Chromium + Bromine → 4. Oxygen + Hydrogen → 5. Calcium + Iodine → 44 Single replacement: _____________ + _______________ If the element forms a + ion replace the + ion of the compound, and if it is a - ion the replace the – ion of the compound. Practice: 1. Aluminum + Magnesium oxide → 2. Copper (II) sulfide + chlorine → 3. Fluorine + Nickel bromide → 45 Double Replacement: ______________ + _____________ Switch the position of the (+) ions. Practice: 1. Aluminum sulfite + Calcium acetate→ 2. Tin (IV) phosphate + Ammonium dichromate → 3. Magnesium chloride + Chromium peroxide → 46 Decomposition Reactions Metallic Chlorates: _____________ ________ + ________ Substitute the specific + ion for the “M” and follow the word equation. Metallic Carbonates: ____________ _______ + ________ Substitute the specific + ion for the “M” and follow the word equation. Metallic Hydroxides: ___________ _______ + _________ Substitute the specific + ion for the “ M “ and follow the word equation. 47 Oxy Acids: Example: Simple Decomposition: __________ ______ + ______ Split the compound into is simpler parts. Practice 1. Potassium sulfide 2. Zinc oxide 48 3. Zinc carbonate → 4. Sodium carbonate → 5. Calcium hydroxide → 6. Aluminum hydroxide → 7. Potassium chlorate → 8. Calcium chlorate → 49 50
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