Chapter11 Student Version Ppt

Chemistry Chapter 11

Chemical Equations and Reactions

Chemical change vs. Physical change

• ____________________– new substance forms with properties that differ from original substance

• the new compound has a different….. • density• boiling point• melting point

• ____________________– A change that does NOT change the substance’s composition.

• evaporation• cutting• melting• freezing

Describing Chemical Reactions

Chemical Change

• A ________________________ is the process by which one or more substances change into one or more new substances.

• _____________________ are the original substances in a chemical reaction.

• ____________________ are the substances that are created in a chemical reaction.

Reactants →Products

Section 1 Describing Chemical Reactions

Evidence of a Chemical Reaction

Section 1 Describing Chemical Reactions

In a chemical reaction

A reaction can be described several ways:

1. ______________________(only words)

• Methane reacts with oxygen gas to form carbon dioxide and water.

2. ________________: (words and symbols)

• methane + oxygen carbon dioxide + water

3. __________________: (formulas and symbols)

CH4 + 2O2 CO2 + 2H2O

Symbols in equations

(→) means “reacts to form”, “yields” or “produces”

(+) means “and” or “reacts with”

(s), (l), (g) after the formula = solid, liquid or gas:

• Ex: AgCl(s), H2O(l), CO2(g)

■ (aq) after the formula = dissolved in water, an aqueous solution:

■Ex: NaCl(aq)

Symbols cont…..

indicates a reversible reaction

shows that heat is supplied to the reaction heat

,

• Physical States: (s, l, g, aq)

NaHCO3(s) + HC2H3O2(aq) NaC2H3O2(aq) + CO2(aq) + H2O(l) solid liquid

aqueous solutions • Reaction Conditions

350°C 25,000 kPa

N2(g) + 3H2(g) 2NH3(g)

Equations and Reaction Information

Word equations (packet pg.1)

Write the word equation:

Ex: When dissolved sodium phosphate reacts with dissolved calcium chloride in water, aqueous sodium chloride and

calcium phosphate powder are made.

Balancing Equations

• The number of atoms for each element must be the same on reactant and product side. Why?

•B/c Mass or atoms cannot be created or destroyed by a chemical or physical change

• A coefficient multiplies the number of atoms of each element in the formula that follows.

Ex: How many atoms of hydrogen and oxygen are in 2H2O:

Balancing Chemical Equations

• Balanced equations show mass conservation

(same number of atoms on both sides)

2Na + 2H2O 2NaOH + H2

• NEVER CHANGE SUBSCRIPTS to balance equations

Unbalanced: H2 + O2 H2O

Incorrect: H2 + O2 H2O2 WHY???

H2O H2O2

You can only add COEFFICIENTS to balance equations.

Correct: 2H2 + O2 2H2O

Balancing cont……

Balancing Chemical Equations (packet p. 2)

Rules:1. Make a t-table2. Count the number of atoms on each side3. Leave H and O last to balance. 4. Add coefficients (not subscripts) to balance • Ex 2: Balance the following equation

___Mg + ___Fe2O3 ___MgO + ___Fe

Balancing Chemical Equations (packet p. 2)

Ex 3: Balance the equation for the reaction of iron(III) oxide with hydrogen to form iron and water.

Balancing Equations and writing chemical equations

____NaOCl + ____H2O2 ____NaCl + ___H2O + ____O2


Balance the following equation.

____Al + ____Fe3O4 ____Al2O3 + ___Fe


Combustion Reactions (packet p. 3 & 4)

________________________________________________________________________________________________________________________________________________

hydrocarbon + oxygen ----> carbon dioxide and water

Combustion of propane:

C3H8 + 5O2 3CO2 + 4H2O

Combustion of ethanol:

CH3CH2OH + 3O2 2CO2 + 3H2O

Synthesis Reactions (combination rxns)(packet p. 3 & 4)

______________________________________________________________________________________.

The general formula for this type of reaction can be shown as:

A + B AB

Ex:C + O2 CO2

CaO(s) + H2O(l) Ca(OH)2(s)

Decomposition Reactions (decompose)(packet p. 3 & 5)

_________________________________________________________________________________________________________________________________

(Opposite of synthesis rxn)

AB ----> A + B

Ex:C12H22O11(s) ----> 12C(s) + 11H2O(g)2Ag2O (s) ----> 4Ag(s) + O2(g)

electricity

____________________________________________________________________________________________________________________

In the case of a positive ion being replaced: A + BC ----> B + AC

orIn the case of a negative ion being replaced:

A + BC ----> C + BA

in either case we have:element + compound ----> element + compound

Examples: Zn(s) + H2SO4(aq) ----> ZnSO4(aq) + H2(g) Cl2(g) + KBr(aq) ----> KCl(aq) + Br2(l)

Single Displacement (packet p. 3 & 5)

Double Displacement Reactions(packet p. 3 & 6)

• _______________________________________________________________________________________________________________________________________

AB + CD CB + AD

orCompound + Compound ----> Compound + Compound

• Examples: HCl(aq) + NaOH(aq) HOH(l) + NaCl(aq) AgNO3(aq) + NaCl(aq) ----> AgCl(s) + NaNO3(aq)

In Summary Synthesis (A + B AB) Decomposition (AB A + B) Combustion

• (carbon-based + oxygen CO2 and water)

Single Displacement• (A + BC B + AC)

Double Displacement• (AB + CD AD + CB)

Packet Examples: pg. 4 Combustion reactions:

Write the balanced combustion equations for the following substances.

1. C3H8

2. C6H14

Packet Examples: p. 4-5 Synthesis Reactions:

Predict the products for the following reactions. Be sure to balance the equations.

1. S6 + O2 (sulfur dioxide)

2. Mg + O2

Packet Examples: p. 5

Decomposition reactions


1. FeO (forms iron and oxygen)

2. Mg(OH)2 (forms magnesium oxide and water)

Reviewing Predictions Na(s) + Cl2(g) →

CO2(g) + H2O(l) → (hydrogen carbonate)

HgO(s) →

CH4 + O2 →

• The activity series ranks the reactivity of elements

•This table will be given to you on the test. (packet p. 5)

Using the Activity Series with Single Displacement rxns: (packet bottom of pg. 5)

Determine if the following reactions will occur. If not write “no reaction” after the arrow. If a reaction does occur, predict the products and balance the equation.

Ex1: Mg + Pb(NO3)2 Ex2: Ni + Fe2O3

Ex3: Zn(s) + 2HCl(aq)

Ex4: Cl2(g) + 2NaBr(aq)

Ex5: Fe(s) + CuSO4(aq)

Chapter 11

Section 3

Precipitate Reactions &

Net Ionic Equations

Review Double Displacement Rxn(packet p. 6)

• In this rxn two compounds in aqueous solution appear to exchange ions and form two new compounds.

AB + CD CB + AD

These are ALL ionic compounds! Cris Cross Charges!!!

• Examples: HCl(aq) + NaOH(aq) HOH(l) + NaCl(aq)

AgNO3(aq) + NaCl(aq) ----> AgCl(s) + NaNO3(aq)

Predicting Displacement Reactions(packet p. 6)


1.Al2O3 + HgCl2

2.AgNO3 + K3PO4

Precipitate Reactions

Most compounds are soluble in aqueous solutions Compounds with low solubility can be considered

insoluble. When two soluble compounds in aqueous solution

are combined and a precipitate forms a new insoluble compound has been formed

sCdSaqNONH2aqNOCdaqSNH 342324

precipitate

Precipitate Reactions

You will use the solubility table to predict if a precipitate will form if two aqueous solutions are combined.

You will also use the solubility table to predict if a reaction will occur in aqueous solution

• If both of the reactants are soluble then a reaction CAN occur

• If one or both reactants is insoluble then NO reaction can occur.

Solubility Rules- will be given on test

Are the following compounds water soluble? a.)KCl b.) NaNO3 c.) AgCl

d.) BaSO4 e.) Ca3(PO4) f.) Pb(ClO3)2

Are the following compounds water soluble? a.) Na(SO4) b.) Mg(ClO3)2 c.) NH4(CO3)

d.) Ba(OH)2 e.) NaCl f.) AgCl

Will a precipitate form if the aqueous solutions are combined? (packet p. 6 double displacement)

a.) K2SO4( ) + Ba(NO3)2 ( )

b.) Na2CO3( ) + MgCl2( )

Will a precipitate form if the aqueous solutions are combined? (packet p. 6 double displacement) cont………

c.) BaSO4 ( ) + KI( )

d.) Ca3(PO4)2( ) + Pb(ClO3)2( )

Net Ionic Equations

Net Ionic Equation – includes ONLY those compounds and ions that undergo a chemical change in a reaction in an aqueous solution.

How to write an ionic equation (2 steps)

Step 1: Convert the chemical equation into an ionic equation (break apart aqueous compounds into its ions)

sCdSaqNONH2aqNOCdaqSNH 342324

sCdSaqNO2 (aq)NH2aq2CdaqS)(2 3432-2

4 NOaqNH

Net Ionic Equations examples(packet bottom of pg. 6)

Ex 1: Write the net ionic equations for the following reaction:

Li3PO4(aq)+3CuSO4(aq) → Cu3PO4 (s) + 3LiSO4(aq)

Step 1- break apart aqueous compounds:

Step 2- Remove spectator ions

Net Ionic Equations examples…

Ex 2: Write the net ionic equations for the following reactions:

Na2SO4(aq) and BaCl2(aq) →

Step 1- break apart aqueous compounds:

Step 2- Remove spectator ions

Chapter 11: Chemical Equations and Reactions

What you should know from Chapter 11:

Terms:1. Chemical reaction2. Chemical equation3. Precipitate4. Coefficient5. Word equation6. Formula equation7. Reversible reaction8. Synthesis reaction9. Decomposition reaction10. Single-replacement reaction11. Double replacement reaction12. Combustion reaction13. Activity series



Concepts:

1. The four indications of a chemical reaction

2. Three characteristics of chemical equations

3. Know how to write a formula equation from a word equation

4. Know how to write a word equation from a formula equation

5. Symbols used in chemical equations

6. The three things that can be determined from a chemical equation

7. The four steps for balancing a chemical equation



Concepts:

8. Identify the five types of chemical reactions

synthesis

decomposition

single replacement

double replacement

combustion

9. Be able to predict the products of simple reactions given the reactants

10. Understand the activity series

11. Use the activity series of elements table to predict is a reaction will occur

12. Be able to write net ionic equations.

Chapter11 Student Version Ppt

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