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Chapters 6 and 7

Chemical Reactions Are SOLID!!

Chapter 6

I. Chemical Reactions and Equations

A. When has a Reaction Occurred?

B. Representing Reactions with

Chemical Equations

C. Balancing Chemical Equations

Chapter 7

I. Precipitation Reactions

A. Ionic Compounds in

Solutions

B. Double Displacement Reactions

II. Acid Base Reactions

III. Oxidation Reduction Reactions

IV. Combustion Reactions

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I. Chemical Reactions and

Equations

A) When has a Reaction Occurred?

B) Representing Reactions with Chemical

Equations

What is a Chemical Equation?

1. 2. 3. 4.

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Recipe for “Maizin’ Potatoes”

2 21+

Balanced Chemical Equation

N2(g) + O2(g) 2NO(g)

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Information Provided by Recipes and

Chemical Equations

- Ratios of ingredients to each other

and to product(s) provide conversion

factors

Difference Between Recipes and Chemical Equations Chemistry - forward and reverse directions of equation

are possible

- for a specific set of conditions one

direction is favored

www.smallstepsproject.org

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How do we treat chemical reactions?

Law of Conservation of Mass

- total mass of all substances after a

chemical rxn is the same as the total mass

before the rxn

http://www3.delta.edu/bernadetteharkness/Ch4AtomicTheoryPart1/Ch4AtomicTheoryPart1_print.html

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Counting Elements

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C. Balancing Chemical Equations Example

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Method For Balancing Chemical Equations

1. Convert statement into chemical

equation and balance the atoms Sulfuryl chloride(SO2Cl2) reacts with hydroiodic acid to form

hydrosulfuric acid, dihydrogen monoxide, hydrochloric acid, and

iodine.

i. Start with elements in only one compound

on either side of the equation

ii. Finish with elements that exist as

monoatomic atoms, diatomic molecules,

triatomic molecules, etc.

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2. Adjust the coefficients to smallest

whole number coefficients

3. Check Answer

4. Specify the states of Matter

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Example (balance)

1. Solid aluminum reacts with aqueous

hydrochloric acid to form aqueous

aluminum chloride and hydrogen gas.

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2. Aqueous calcium phosphate reacts

with solid silicon dioxide and solid carbon

(C(s)) to form solid phosphorus, solid

calcium silicate (SiO32-

), and gaseous carbon

monoxide.

3. Fe(OH)3(s) + H2SO4(aq) Fe2(SO4)3(aq) + H2O(l)

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Another Way of Looking at Chemical

Reactions

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Chapter 7 Reactions in Aqueous Solution

WHICH IONIC COMPOUNDS WILL DISSOLVE?

Ionic (in water)

Soluble Insoluble

Dissociates into cations and anions

Stays intact

Molecular (in water)

Acids

(soluble)

Bases (N)

(soluble)

Neither Acid or Base

(soluble or insoluble)

Strong Acid Weak Base Weak Acid

Stays Intact H3O

+ + anion Stays Intact

Stays Intact

Solubility Rules for Common Ionic Compounds

SOLUBLE COMPOUNDS

group 1 cations + any anion soluble

ammonium ion + any anion soluble

Any cation + nitrate, perchlorate, soluble

or acetate ions

MOSTLY SOLUBLE COMPOUNDS

Any cation + chloride, bromide, soluble

or iodide ions (except lead(II), silver, mercury(I) insoluble)

Any cation + sulfate ions soluble (except strontium, calcium, barium, lead(II), mercury(I) insoluble)

INSOLUBLE COMPOUNDS

Any cation + hydroxide ions insoluble (except group I, ammonium, calcium*, barium*, strontium* soluble)

Any cation + sulfide ions Insoluble (except group I, ammonium, group II* soluble)

Any cation + carbonate or Insoluble

phosphate ions (except group I, ammonium soluble)

* - slightly soluble (for chem 130 = soluble)

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Representing Ionic Compounds in Water