NOTES: CHEMICAL REACTIONS



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|UNIT 4: Chemical Reactions – Stoichiometry and Thermodynamics |

|Part A: Chemical Reactions |

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|Big Picture Ideas: |

|The identity of the reactants helps scientists to predict the products in a chemical reaction. |

|Quantitative relationships exist with all chemical reactions that allow scientists to predict amounts of products formed, reactants consumed, |

|and percent yield based on theoretical maximum. |

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|Big Picture Question: How can you predict the products in a chemical reaction? |

|Suggested Resources… |

|Homework Assignments |

|Classwork Assignments |

|Laboratory Activities |

|Formative Assessments |

|Textbook pages: Chapter 9 |

|Websites: |

|Key Terms: |

|chemical reaction |

|chemical equation |

|reactants |

|yields |

|products |

|coefficient/mole |

|subscript |

|diatomic molecules |

|synthesis/direct combination |

|decomposition |

|single replacement/displacement |

|double replacement/displacement |

|combustion |

|activity series |

|aqueous |

|kinetics |

|catalyst |

|surface area |

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|Directions: Use this information as a general reference tool to guide you through this unit. Don’t hesitate to ask your teacher for help! |

|By the conclusion of this unit, you should know the following: |By the conclusion of this unit, you should be able to do the following: |

|There are five basic types of chemical reactions (S, D, SR, DR, Comb.)|Balance chemical reactions. |

|that exhibit distinct patterns for the prediction of products. |Identify type of chemical reaction. |

|Experimental evidence can be used to identify products in a reaction. |Identify if a reaction will occur using an activity series. |

|All reactions follow the Law of Conservation of Matter (balancing |Predict products for a reaction. |

|equations). |Write balance formula equation given chemical equation (words). |

|Symbols are used to identify different aspects of a chemical reaction |Using the collision theory, explain how altering the temperature, surface |

|(states of matter, catalysts, heat, etc.). |area, concentration and the addition of a catalyst affects the rate of a |

|Collision theory describes characteristics for a successful reaction. |reaction. |

|Factors can be altered to affect the rate of a reaction (temperature, | |

|surface area, catalyst, concentration). | |

1. What type of reaction is it?

a. element + element (

b. ionic compound + ionic compound (

c. element + ionic compound (

d. compound (

e. compound + oxygen (

2. How can you tell if a chemical change has taken place? List examples.

3. Define a chemical reaction. Why must we balance chemical equations? (if it is a “must” there must be a “law” governing the concept).

4. Balance each reaction below. Identify each type the following reactions are:

a)  NaOH(aq) + Pb(NO3)2(aq) --> NaNO3(aq) + Pb(OH)2(s)

b)  CH4(g) + O2(g) --> CO2(g) + H2O(l)

c)  Fe(s) + NaBr(aq) --> FeBr3(aq) + Na(s)

d)  Pb(s) + O2(g) --> PbO (g)

e)  Na2CO3(s) --> Na2O(s) + CO2(g)

5. Complete and balance each reaction below:

a) Mg + HCl ( _________ + ____________

b) C2H6 + O2 ( _________ + ____________

c) CaF2 + Na2SO4 ( _________ + ____________

d) Sr + N2 ( __________

6. List three factors effecting the rate of a chemical reaction. Know why they effect the reaction rate (collision theory!)

NOTES: CHEMICAL REACTIONS

VOCABULARY:

Products what is formed in a chemical reaction; right of arrow

Reactants what goes into a chemical reaction; left of arrow

( yields

+ and

(s) solid

(l) liquid

(g) gas

(aq) aqueous – only works when dissolved in water

Catalyst a substance that speeds up a reaction but is not itself consumed; provides an easier reaction pathway that requires less activation energy

Activation Energy (Ea) energy necessary to initiate a chemical reaction

ENERGY OF CHEMICAL REACTIONS:

Exothermic Reaction: ΔH is – Endothermic Reaction: ΔH = +

(heat is a “product”) (heat is a “reactant”)

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KINETICS: RATE OF CHEMICAL REACTIONS

Collision Theory: for a reaction to occur, the reactants must collide with sufficient energy and with the proper orientation (and in the correct ratio)

Factors Affecting Reaction Rate:

1. Temperature

if temperature is increased, the reaction will be quicker.

faster moving particles collide more often, and more particles will have enough energy (Ea) when they collide

2. Particle size (surface area)

more exposed particles causes more collisions, so there will be more collisions with the correct orientation

3. Nature of Reaction

reaction rate is also determined by the properties of the reactants

4. Adding a Catalyst or Inhibitor

a catalyst speeds up a reaction by lowering the required activation energy

an inhibitor slows down a reaction by raising the activation energy

BALANCED CHEMICAL REACTIONS

Law of Conservation of Matter: matter cannot be created or destroyed in a chemical reaction

WORD ( FORMULA ( BALANCED EQUATIONS

1. word equation: Hydrogen gas reacts with oxygen gas to form water

formula equation: ____ H2 + O2 ( H2O ___________________________________________

diagram: H – H + O = O ( O + O

H – H H H H H

balanced reaction ____2 H2 + O2 ( 2 H2O ___________________________________________

2. word equation: Magnesium reacts with hydrochloric acid solution (HCl in water) to form

magnesium chloride and hydrogen.

Formula equation: ____ Mg + HCl ( MgCl2 + H2 __________________________________

diagram: Mg + H – Cl ( Cl-1Mg+2Cl-1 + H – H

H – Cl

balanced reaction _______ Mg + 2 HCl ( MgCl2 + H2 ________________________________

Try balancing these chemical reactions:

a. 2Na + H2SO4 ( Na2SO4 + H2

b. 2 K + Cl2 ( 2 KCl

c. S8 + 8 O2 ( 8SO2

d. 3F2 + 2 FeBr3 ( 2 FeF3 + 3Br2

e. 3H2SO4 + 2 Al ( Al2(SO4)3 + 3H2

f. 2 C2H6 + 7 O2 ( 4CO2 + 6H2O

g. 2 NaNO3 + Ca(MnO4)2 ( 2 NaMnO4 + Ca(NO3)2

h. SKIP P4 + KClO3 ( KCl + P2O5

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ANSWERS:

1) 1 + 3 ( 2

2) 2 ( 2 + 3

3) 2 + 1 ( 2 + 1

4) 2 + 1 ( 2

5) 1 + 2 ( 2 + 1

6) 2 + 3 ( 6 + 1

7) 1 + 2 ( 1 + 2

8) 1 + 5 ( 3 + 4

9) 2 + 25 ( 16 + 18

10) 1 + 3 ( 1 + 3

11) 4 + 5 ( 2

12) 2 + 2 ( 2 + 1

13) 2 ( 4 + 1

14) 1 + 12 ( 8

15) 6 + 6 ( 1 + 6

16) 2 + 1 ( 2 + 1

17) 2 + 1 ( 1 + 1 + 1

18) 1 + 1 ( 1 + 1 + 1

19) 2 + 1 ( 2

20) 2 + 1 ( 2 + 1

SYNTHESIS, DECOMPOSITION AND COMBUSTION REACTIONS

Types of Reactions: Synthesis, Decomposition and Combustion

Synthesis – A + B ( AB (1 product only)

Decomposition – AB ( A + B (1 reactant only)

Combustion of a hydrocarbon – CxHy + O2 ( CO2 + H2O

Practice:

Balance each reaction below. Then identify the reaction type.

a. H2 + Br2 ( 2 HBr __synthesis______________

b. C4H8 + 6 O2 ( 4 CO2 + 4 H2O __combustion____________

c. 2 NaOH ( Na2O + H2O __decomposition__________

d. Ba(ClO3)2 ( BaCl2 + 3 O2 __decomposition__________

First write and balance the equation. Then identify the reaction type.

e. phosphorus + oxygen ( tetraphosphorus decoxide __ synthesis _____________

4 P + 5 O2 ( P4O10

f. pentane (C5H12) + oxygen ( carbon dioxide + water __ combustion ____________

C5H12 + 8 O2 ( 5 CO2 + 6 H2O

g. magnesium chlorate ( magnesium chloride + oxygen ___ decomposition _________

Mg(ClO3)2 ( MgCl2 + 3 O2

h. when solid calcium carbonate is heated calcium oxide and carbon dioxide are formed

___ decomposition _________

CaCO3 ( CaO + CO2

i. the formation of calcium nitride from calcium and nitrogen ___ synthesis _____________

3 Ca + N2 ( Ca3N2

j. sulfur trioxide mixes with water in the atmosphere to form sulfuric acid ___ synthesis ________

SO3 + H2O ( H2SO4

NOTES: SINGLE DISPLACEMENT REACTIONS & DOUBLE DISPLACEMENT REACTIONS

1. Single Displacement Reactions (aqueous ONLY)

metals:

standard: A(s) + BX (aq) ( AX (aq) + B(s)

example: Cu + 2 AgNO3 ( Cu(NO3)2 + 2 Ag

metal + acid:

standard: A(s) + HX (aq) ( AX (aq) + H2(g)

example: Mg + 2 HCl ( MgCl2 + H2

metal + water:

standard: A(s) + H2O(l) ( AOH(aq) + H2(g)

example: 2 K + 2 H2O ( 2 KOH + H2

halogens:

standard: X2 + AY ( AX + Y2

example: F2 + 2 KI ( 2 KF + I2

2. Double Displacement (aqueous only)

standard : AX (aq) + BY (aq) ( AY(aq) + BX(s)

example : Ba(NO3)2 + NaI ( BaI2 + NaNO3

3. Identify the reaction type for each reaction below. Then complete and balance the reaction.

_single displacement_ a. Ba + 2 AgNO3 ( Ba(NO3)2 + 2Ag

__single displacement________b. F2 + 2KI ( 2 KF + I2

__double displacement c. NaOH + CaCl2 ( _2 NaCl + Ca(OH)2

___single displacement d. Zn + H2SO4 ( ZnSO4 + H2

WRITING WORD EQUATIONS

__decomposition_______________1. aluminum chlorate ( aluminum chloride + oxygen

2 Al(ClO3)3 ( 9 O2 + 2 AlCl3

__SR_______________ 2. lithium + iron (III) nitrate ( lithium nitrate + iron

3 Li + Fe(NO3)3 ( 3 LiNO3 + Fe

__decomposition_______________ 3. magnesium carbonate ( magnesium oxide + carbon dioxide

MgCO3 ( MgO + CO2

__synthesis____________ 4. tin + nitrogen ( tin (IV) nitride

3 Sn + 2 N2 ( Sn3N4

__SR____________ 5. Zinc reacts with nitric acid to form zinc nitrate and hydrogen

Zn + 2 HNO3 ( Zn(NO3)2 + H2

__decomposition__________6. calcium hydroxide breaks down to form calcium oxide and water

Ca(OH)2 ( CaO + H2O

WRITING WORD EQUATIONS WITH PREDICTING PRODUCTS

__synthesis_______________ 1. aluminum + oxygen (

4 Al + 3 O2 ( 2 Al2O3

__SR____________ 2. sodium + silver nitrate (

Na + AgNO3 ( NaNO3 + Ag

__SR_______________ 3. magnesium + hydrochloric acid (

Mg + 2 HCl ( MgCl2 + H2

___DR______________ 4. solutions of iron (III) nitrate + potassium sulfate are mixed (

2 Fe(NO3)3 + 3 K2SO4 ( Fe2(SO4)3 + 6 KNO3

____SR_____________ 5. Chlorine gas is bubbled through a solution of lithium iodide (

Cl2 + 2 LiI ( 2 LiCl + I2

Fun With Predicting Reaction Products

Predict the products of each of the following chemical reactions. If a reaction will not occur, explain why not:

1) ____ Ag2SO4 + __2__ NaNO3 ( 2 AgNO3 + Na2SO4

2) __2__ NaI + ____ CaSO4 ( CaI2 + Na2SO4

3) __2__ HNO3 + ____ Ca(OH)2 ( 2 H2O + Ca(NO3)2

4) ____ Zn + ___2__ HNO3 ( Zn(NO3)2 + H2

5) ____ AlCl3 + ____ (NH4)3PO4 ( AlPO4 + 3 NH4Cl

6) ___3_ Pb + ___2_ Fe(NO3)3 ( 3 Pb(NO3)2 + 2 Fe

7) ___2_ C3H6 + __9__ O2 ( 6 CO2 + 6 H2O

8) __2__ Na + ____ CaSO4 ( Na2SO4 + Ca

WRITING WORD EQUATIONS

a. lithium + nitrogen ( lithium nitride

6 Li + N2 ( 2 Li3N

b. aluminum + oxygen ( aluminum oxide

4 Al + 3 O2 ( 2 Al2O3

c. sodium carbonate ( sodium oxide + carbon dioxide

Na2CO3 ( Na2O + CO2

d. zinc + phosphoric acid ( zinc phosphate + hydrogen gas

3 Zn + 2 H3PO4 ( Zn3(PO4)2 + 3 H2

e. chlorine gas + lithium iodide ( lithium chloride + iodine

Cl2 + 2 LiI ( 2 LiCl + I2

f. sodium hydroxide ( sodium oxide + water

2 NaOH ( Na2O + H2O

g. magnesium reacts with hydrochloric acid to form magnesium chloride and hydrogen gas

Mg + 2 HCl ( MgCl2 + H2

h. solutions of iron (III) chloride and sodium hydroxide react to form iron (III) hydroxide and sodium chloride

FeCl3 + 3 NaOH ( Fe(OH)3 + 3 NaCl

i. when sodium is added to water, sodium hydroxide and hydrogen gas are produced\

2 Na + 2 H2O ( 2NaOH + H2

j. when zinc is placed in a solution of lead (II) nitrate, zinc nitrate and solid lead metal are formed

Zn + Pb(NO3)2 ( Zn(NO3)2 + Pb

HOMEWORK: BALANCING CHEMICAL REACTIONS NAME:

DATE:

1. ___P4 + _5__O2 ( _2__P2O5

2. _2__Al + _6__HCl ( _2__AlCl3 + _3__H2

3. ___Al2(SO4)3 + _3__Ca(OH)2 ( _2__Al(OH)3 + _3__CaSO4

4. _8__H2S + _8__Cl2 ( ___S8 + _16__HCl

5. _3___Mg + ____N2 ( ____Mg3N2

6. _3___Fe + _4___H2O ( ____Fe3O4 + _4___H2

7. _2___NaOH + ____Cl2 ( ____NaCl + ____NaClO + ____H2O

8. _2___C4H10 + _13___O2 ( _8___CO2 + _10___H2O

9. __2___CH3OH + __3___O2 ( _2___CO2 + __4___ H2O

HOMEWORK: SYNTHESIS, DECOMPOSITION AND COMBUSTION REACTIONS

1. Classify each equation below as synthesis, decomposition or combustion. Then balance each equation.

__decomposition_________________ 1. 2 NaClO3 ( 2 NaCl + 3 O2

__synthesis______________________ 2. 2 Cu + S ( Cu2S

__synthesis______________________ 3. 2 S + 3 O2 ( 2 SO3

__combustion___________________ 4. 2 C3H6 + 9 O2 ( 6 CO2 + 6 H2O

2. Classify each equation below as synthesis, decomposition or combustion. Write and balance the equation for the reaction.

water

_decomposition_______________________ 1. potassium hydroxide ( potassium oxide + hydrogen

2 KOH ( K2O + H2O

__combustion______________________ 2. dicarbon tetrahydride + oxygen ( carbon dioxide + water

C2H4 + 3 O2 (2 CO2 + 2 H2O

__decomposition_____________________ 3. lithium chlorate ( lithium chloride + oxygen

2 LiClO3 ( 2 LiCl + 3 O2

__synthesis______________________ 4. magnesium + nitrogen ( magnesium nitride

3 Mg + N2 ( Mg3N2

__synthesis_____________________ 5. aluminum burns in pure oxygen to form aluminum oxide

4 Al + 3 O2 (2 Al2O3

__decomposition__________ 6. sodium carbonate is heated to form sodium oxide and carbon dioxide

Na2CO3 ( Na2O + CO2

__synthesis_____________________ 7. water and dinitrogen pentoxide combine to form nitric acid

H2O + N2O5 ( 2 HNO3

CLASSIFICATION OF CHEMICAL REACTIONS

Classify the reactions below as synthesis, decomposition, single replacement or double replacement:

1. 2H2 + O2 ( 2H2O _____synthesis_& combustion ______

2. 2H2O ( 2H2 + O2 ______decomposition_______________

3. Zn + H2SO4 ( ZnSO4 + H2 ______single____________________

4. 2CO + O2 ( 2CO2 ______synthesis__& combustion_____

5. 2HgO ( 2Hg + O2 _____decomposition__________

6. 2 KBr + Cl2 ( 2 KCl + Br2 _____single_____________________

7. CaO + H2O ( Ca(OH)2 ____synthesis______________________

8. AgNO3 + NaCl ( AgCl + NaNO3 ____double______________________

9. 2 H2O2 ( 2H2O + O2 ____decomposition_______________

10. Ca(OH)2 + H2SO4 ( CaSO4 + 2H2O ___double_______________________

11. Copper metal is put into a solution of silver nitrate. Solid silver precipitates, and copper (II) nitrate solution is formed.

Cu + 2 AgNO3 ( 2 Ag + Cu(NO3)2 single displacement

12. Methane gas burns in pure oxygen to give carbon dioxide and water

CH4 + 2 O2 ( CO2 + 2 H2O combustion of a hydrocarbon

13. When sodium carbonate is heated, it breaks down to form sodium oxide and carbon dioxide.

Na2CO3 ( Na2O + CO2 decomposition

HOMEWORK – PRACTICE REACTION WRITING

Identify the reaction type for each reaction written below. Then write the balanced equation for each reaction.

____single displacement___ 1. Magnesium is placed in a solution of aluminum nitrate

3 Mg + 2 Al(NO3)3 (3 Mg(NO3)2 + 2 Al

_______synthesis________________ 2. Calcium burns in pure oxygen.

2 Ca + O2 ( 2CaO

____combustion hydrocarbon_____ 3. The combustion of propane (C3H8)

__________C3H8 + 5 O2 ( 3 CO2 + 4 H2O_________________

____single displacement_____ 4. Fluorine is bubble through a solution of sodium bromide

__________F2 + 2 NaBr ( 2 NaF + Br2 _______________________________________

___double displacement______ 5. Solutions of potassium chloride and barium hydroxide are mixed.

_____2 KCl + Ba(OH)2 ( 2 KOH + BaCl2 ______________________________

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