chapter 11 chemical reactions chemical equation describes chemical reaction. describes chemical...

Download Chapter 11 Chemical Reactions Chemical Equation Describes chemical reaction. Describes chemical reaction. Chemical equation: reactants yield products

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Slide 2 Chapter 11 Chemical Reactions Slide 3 Chemical Equation Describes chemical reaction. Describes chemical reaction. Chemical equation: reactants yield products Chemical equation: reactants yield products Reactants Products Reactants Products Much easier to write symbols and formulas instead of words Much easier to write symbols and formulas instead of words Slide 4 Examples Solid Iron reacts with oxygen gas to form the solid IronIIIoxide. Solid Iron reacts with oxygen gas to form the solid IronIIIoxide. iron(s) + oxygen(g) ironIIIoxide(s) iron(s) + oxygen(g) ironIIIoxide(s) Fe(s) + O 2 (g) Fe 2 O 3 (s) Fe(s) + O 2 (g) Fe 2 O 3 (s) Carbon tetrahydride gas BURNS to form carbon dioxide gas and water vapor. Carbon tetrahydride gas BURNS to form carbon dioxide gas and water vapor. Carbon tetrahydride(g) + oxygen(g) carbon dioxide() + water() Carbon tetrahydride(g) + oxygen(g) carbon dioxide() + water() CH 4 (g) + O 2 (g) CO 2 () + H 2 O() CH 4 (g) + O 2 (g) CO 2 () + H 2 O() Skeleton Equation: chemical equation that tells you what the reactants and products are but NOT how much of each you have. Skeleton Equation: chemical equation that tells you what the reactants and products are but NOT how much of each you have. First step in writing a chemical equation. First step in writing a chemical equation. Slide 5 Symbols Used (s) solid (s) solid (l) liquid (l) liquid (g) gas (g) gas ()gas as a product ()gas as a product (aq) aqueous (in water solution) (aq) aqueous (in water solution) ppt (precipitate) solid product from 2 aqueous reactants ppt (precipitate) solid product from 2 aqueous reactants means with heat means with heat Ptmeans with Platinum catalyst: speeds up a reaction without being used. Ptmeans with Platinum catalyst: speeds up a reaction without being used. reversible reaction reversible reaction Slide 6 Balancing Chemical Equations Balanced equations have: Balanced equations have: the same # of atoms of each element on BOTH sides of the equation. the same # of atoms of each element on BOTH sides of the equation. Law of Conservation of Mass atoms can neither be created nor destroyed, simply rearranged. Law of Conservation of Mass atoms can neither be created nor destroyed, simply rearranged. Slide 7 Rules for Balancing Equations Get the correct formulas for reactants and products. Get the correct formulas for reactants and products. (USE ION CHART AND DONT FORGET DIATOMIC ELEMENTS!) (USE ION CHART AND DONT FORGET DIATOMIC ELEMENTS!) Write reactants on left, products on right. Use plus signs to separate compounds and yield sign to separate the reactants from products. Write reactants on left, products on right. Use plus signs to separate compounds and yield sign to separate the reactants from products. Slide 8 Rules Continued Count the # of atoms of each element in reactants and products. (Polyatomic atoms on both sides count as one.) Count the # of atoms of each element in reactants and products. (Polyatomic atoms on both sides count as one.) Balance # of each element using coefficients. Balance # of each element using coefficients. Coefficient small whole # in front of a formula. Coefficient small whole # in front of a formula. NEVER CHANGE FORMULA SUBSCRIPTS NEVER CHANGE FORMULA SUBSCRIPTS Slide 9 Rules for Balancing Equations Balance elements appearing 3 or more places LAST. Balance elements appearing 3 or more places LAST. Check each element to make sure equation is balanced. Check each element to make sure equation is balanced. Make sure all coefficients are in the lowest whole number ratio. Make sure all coefficients are in the lowest whole number ratio. Do not change subscripts!!! Slide 10 Diatomic Molecules Diatomic Molecules- a molecule made up two atoms of the same element. They are only diatomic when they are alone. -There are 7 naturally occurring diatomic molecules. H O N Cl Br I F Slide 11 Balancing Examples ___ C(s) + ___ O 2 (g) ___ CO 2 (g) ___ C(s) + ___ O 2 (g) ___ CO 2 (g) ___ C(s) + ___ O 2 (g) ___ CO (g) ___ C(s) + ___ O 2 (g) ___ CO (g) ___ AgNO 3 (aq) + ___Cu(s) ___ Cu(NO 3 ) 2 (aq) + ___ Ag(s) ___ AgNO 3 (aq) + ___Cu(s) ___ Cu(NO 3 ) 2 (aq) + ___ Ag(s) ___ Al(s) + ___ O 3 (g) ___ Al 2 O 3 (s) ___ Al(s) + ___ O 3 (g) ___ Al 2 O 3 (s) *___ C 2 H 6 (g) + ___ O 2 (g) ___ CO 2 (g) + ___ H 2 O(g) *___ C 2 H 6 (g) + ___ O 2 (g) ___ CO 2 (g) + ___ H 2 O(g) *___ H 3 PO 3 ___ H 3 PO 4 + PH 3 *___ H 3 PO 3 ___ H 3 PO 4 + PH 3 Slide 12 5 Types of Chemical Reactions Combination Reaction elements combine to form a compound. Combination Reaction elements combine to form a compound. A + B AB A + B AB element + element compound element + element compound Ex. Sodium + chlorine sodium chloride Ex. Sodium + chlorine sodium chloride ___Na(s) + ___ Cl 2 (g) ___ NaCl(s) ___Na(s) + ___ Cl 2 (g) ___ NaCl(s) 22 Slide 13 5 Types of Reactions Decomposition Reaction compound breaks down into its element. Decomposition Reaction compound breaks down into its element. AB A + B AB A + B compound element + element compound element + element Ex: MercuryII oxide mercury + oxygen Ex: MercuryII oxide mercury + oxygen ___ HgO ___Hg + ___O 2 ___ HgO ___Hg + ___O 2 22 Slide 14 5 Types of Reactions - 3 Single Replacement Reaction one element replaces another element in a compound. AB + C A + CB AB + C A + CBor AB + D AD + B AB + D AD + B + - + + + - + - - + - - Slide 15 Examples of Single Replacement Reactions Must use Activity Series to see if reaction works Zinc + sulfuric acid zinc sulfate + hydorgen Zn(s) + H 2 SO 4 (aq) ZnSO 4 (aq) + H 2 () Periodic table is activity series for halogens Sodium bromide + chlorine sodium chloride + bromine ___NaBr(s) + ___Cl 2 (g) ___NaCl(s) + ___Br 2 () 22 Slide 16 5 Types of Reactions Double Replacement Reaction two compounds react and exchange positive ions to form two new compounds. AB + CD AD + CB AB + CD AD + CB Barium Chloride(aq) + potassium carbonate(aq) barium carbonate( ) + potassium chloride(aq) Barium Chloride(aq) + potassium carbonate(aq) barium carbonate( ) + potassium chloride(aq) BaCl 2 (aq) + K 2 CO 3 (aq) BaCO 3 ( ) + ___ KCl(aq) BaCl 2 (aq) + K 2 CO 3 (aq) BaCO 3 ( ) + ___ KCl(aq) + - + - + - + - 2 Slide 17 5 Types of Reactions Combustion Reaction oxygen reacts with a compound composed of C and H. C x H y + O 2 CO 2 + H 2 0 C x H y + O 2 CO 2 + H 2 0 Also called Burning (exothermic) The products are always CO 2 and H 2 O. Slide 18 Examples of Combustion Reactions 1. C 6 H 6 + O 2 CO 2 + H 2 O 2. CH 3 OH + O 2 CO 2 + H 2 O 367 21 CH 3 OH + O 2 CO 2 + H 2 O2 3 2 4 C 6 H 6 + O 2 CO 2 + H 2 O 2 15 12 6 Slide 19 Special Decomposition Reactions: Decomposition of a Carbonate: Decomposition of a Carbonate: Metal carbonate metal oxide + carbon dioxide Metal carbonate metal oxide + carbon dioxide XCO 3 XO + CO 2 ex. Na 2 CO 3 Na 2 O + CO 2 Slide 20 Special Decomposition Reactions: Decomposition of a Hydroxide: Decomposition of a Hydroxide: Metal hydroxide metal oxide + water Metal hydroxide metal oxide + water XOH XO + H 2 O ex. 2NaOH Na 2 O + H 2 O Slide 21 Special Decomposition Reactions: Decomposition of a Chlorate: (ClO 3 ) Decomposition of a Chlorate: (ClO 3 ) Metal chlorate metal chloride + oxygen Metal chlorate metal chloride + oxygen XClO 3 XCl + O 2 XClO 3 XCl + O 2 ex. ___NaClO 3 ___NaCl + ___O 2 2 3 Slide 22 Special Decomposition Reactions: 4 Special single Replacement Reaction: Special single Replacement Reaction: Group IA or IIA metal and H 2 O X + HOH XOH + H 2 ex. 2Na + 2HOH 2NaOH + H 2 Slide 23 How to ID types of reactions. Combination Reactions given 2 items that form 1 new compound. Decomposition Reactions given a single compound that breaks into parts. Single Replacement given a single element plus a single compound, forms a new compound a a different element. Double Replacement given two compounds (+s change places). Combustion Reaction given CH compound with Oxygen, always forms water and carbon dioxide. Slide 24

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