Chemical Reactions 1

Chapter 7 Vocabulary Words Reactant Product Chemical Energy Exothermic Reaction Endothermic Reaction Chemical Equation Mole Ratio Synthesis Reaction Decomposition Reaction Combustion Reaction Single-Replacement Reaction Double Replacement Reaction Free Radical Oxidation-Reduction Reaction Catalyst Enzyme Substrate Chemical Equilibrium 2

What are elements made of? atoms What are chemical compounds made of? Two or more atoms of different elements What are the different types of compounds? Ionic  Metal + Nonmetal Covalent  Nonmetal + Nonmetal 3

3CuCl 2 + 2Al  2AlCl 3 + 3Cu reactantsproducts “yields” coefficient subscript 4

Types of Chemical Reactions 1.Synthesis 2.Decomposition 3.Single displacement 4.Double displacement 5

1. Synthesis reactions Occur when two substances combine and form 1 new compound A + B  AB Reactant + Reactant  1 Product Ex: 2H 2 + O 2  2H 2 O Ex: C + O 2  CO 2 6

2. DecompositionRxns Compound breaks up into elements or into smaller, simpler compounds AB  A + B 1 Reactant  Product + Product Ex: 2 H 2 O  2H 2 + O 2 7

Practice Identify the type of reaction for each of the following synthesis or decomposition reactions N 2 + O 2  BaCO 3  Co + S  NH 3 + H 2 CO 3  NI 3  8 2 NO (NH 4 ) 2 CO 3 N 2 + I 2 Co 2 S 3 BaO + CO 2 Synthesis Decomposition Synthesis Decomposition

Types of Reactions 1.Synthesis 2.Decomposition 3.Single displacement 4.Double displacement 9

3. Single Replacement Reactions Occur when one element replaces another in a compound. AB + C  CB + A Ex: CuCl 2 + 2Al  2AlCl 3 + 3Cu 10

Double Replacement Rxns Occurs when two elements swap places with one another *AB + CD  AD + CB Ex: Pb(NO 3 ) 2 + K 2 CrO 4  PbCrO 4 + 2KNO 3 11

Practice Identify the type of reaction. Pb(NO 3 ) 2 + 2KI  PbI 2 + 2KNO 3 Zn + 2HCl → ZnCl 2 + H 2 Fe + Cu(NO 3 ) 2 → Fe(NO 3 ) 2 + Cu FeS + HCl  FeCl 2 + H 2 S 12 SR DR SR DR

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Counting Atoms CaCO 3 Ca= C= O= C 2 H 4 O 2 C= H= O= 2Li 3 AsO 4 Li= As= O= 2Ca(AlO 2 ) 2 Ca= Al= O= 14

BR: What is a chemical reaction? Describe it in your own words. EQ: In a chemical equation, where are the: Products? Reactants? 15 SPS2. Apply the Law of Conservation of Matter by balancing the following types of reactions: Synthesis Decomposition, Single replacement, and Double replacement. Left/Beginning Right/End

Mg + 2HCl  MgCl 2 + H 2 What are the reactants in this reaction? What are the products in this reaction? Mg and HCl MgCl 2 + H 2

Balancing Chemical Equations According to the Law of Conservation of Matter, atoms are not ____created______ or __destroyed___ during a chemical reaction. Scientists know that there must be the __same________ number of atoms on each ____side_________ of the ______equation______. To balance the chemical equation, you must place _______coefficients_____________ in front of the chemical formulas in the equation. You cannot __add______ or ____change______ subscripts!

How to balance an equation... 1) Count the number of atoms for each type of element on the reactants and products sides of the equation. 2) Pick an element that is not equal on both sides of the equation. 3) Place a coefficient in front of the formula with that element 4) Adjust your counts. 5) Continue placing coefficients to get the same number of atoms of each element on each side. Reduce your coefficients if possible.

Practice ___Mg + ___O 2  ___MgO

___N 2 + ___H 2  ___NH 3

___Cu 2 O + ___C  ___Cu + ___CO 2

___H 2 O 2  ___H 2 O + ___O 2

Balancing Chemical Equations BR: What do you use to balance chemical equations? Coefficients EQ: What law requires us to balance our chemical equations? Law of Conservation of Matter

Identify each type of reaction by their general equation: a. AB  A + B b. AB + C  CB + A c. A + B  AB d. AB + CD  AD + CB 25 Decomposition Single Replacement Double Replacement Synthesis

___Ca + ___O 2  ___CaO

Endothermic vs. Exothermic Reactions

Balancing Chemical Equations Iron(III) hydroxide breaks down to form iron(III) oxide and water. 28

Balancing Chemical Equations Aluminum fluoride combines with magnesium nitrate to form aluminum nitrate and magnesium fluoride. 29

Balancing Chemical Equations Calcium chloride combines with hydrogen sulfate to form calcium sulfate and hydrogen chloride. 30

Balancing Chemical Equations Aluminum fluoride combines with magnesium nitrate to form aluminum nitrate and magnesium fluoride.

Balancing Chemical Equations Iron(III) hydroxide breaks down to form iron(III) oxide and water.

Balancing Chemical Equations Calcium chloride combines with hydrogen sulfate to form calcium sulfate and hydrogen chloride.

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Classifying and Balancing Chemical Reactions Part 3 6. AgNO 3 + KCl  AgCl + KNO 3 already balanced 7. 2H 2 O 2  2H 2 O + O 2 8. (NH 4 ) 2 SO 4 + Ba(NO 3 ) 2  BaSO 4 + 2NH 4 NO 3 9. MgI 2 + Br 2  MgBr 2 + I 2 already balanced 10. SO 3 + H 2 O  H 2 SO 4 already balanced

Write the chemical equations and balance them... 2AlF 3 + 3Mg(NO 3 ) 2  2Al(NO 3 ) 3 + 3MgF 2 CaCl 2 + H 2 SO 4  CaSO 4 + 2HCl 2Fe(OH) 3  Fe 2 O 3 + 3H 2 O

Write the following chemical equations in words and balance them... 2Al + 3CuSO 4  Al 2 (SO 4 ) 3 + 3Cu Aluminum and copper (II) sulfate yield aluminum sulfate and copper. SiO 2 + 2C  Si + 2CO Silicon dioxide plus carbon form silicon plus carbon monoxide. 2CaCO 3  2Ca + 2C + 3O 2 Calcium carbonate produces calcium, carbon, and oxygen.

Write the reaction in words and balance the equation. 1.K + H 2 O  KOH + H 2 potassium + dihydrogen oxide (water)  potassium hydroxide + hydrogen 2.CuCl 2 + Al  AlCl 3 + Cu copper (II) chloride + aluminum  aluminum chloride + copper 40

Write the chemical equation and balance. 1.Aluminum and oxygen gas (O 2 ) combine to form aluminum oxide. Al + O 2  Al 2 O 3 2. Carbon and iron(III)oxide react to form iron and carbon dioxide. C + Fe 2 O 3  Fe + CO 2 41