Presentation is loading. Please wait.

Presentation is loading. Please wait.

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

Similar presentations


Presentation on theme: "Chapter 11 Chemical Reactions Chemical Equation Describes chemical reaction. Describes chemical reaction. Chemical equation: reactants yield products."— Presentation transcript:

1

2 Chapter 11 Chemical Reactions

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

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.

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

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.

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 DON”T FORGET DIATOMIC ELEMENTS!) (USE ION CHART AND DON”T 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.

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

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!!!

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

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

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

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

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

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

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)

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.

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 367½ 21½ CH 3 OH + O 2 CO 2 + H 2 O C 6 H 6 + O 2 CO 2 + H 2 O

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

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

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

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

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.

24


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

Similar presentations


Ads by Google