1.2 Essential Review – Chemical Reactions

1. Synthesis

2. Decomposition

3. Single Displacement

4. Double Displacement

5. Combustion

6. Acid-Base Neutralization

What are the 6 main reactions?

Two or more species react to produce a new reagent (or reagents).

How does Synthesis work?

A single reactant breaks down into two or more simple products.

How does Decomposition work?

One element is replaced by another more reactive element (Example: Redox Reactions)

How do Single Displacement rxns work?

The positive or negative ions of two ionic compounds replace each other.

How do Double Displacement rxns work?

- a compound reacts with an oxidant (usually oxygen) in a highly exothermic reaction

- for hydrocarbons, the products are carbon dioxide and water.

How do Combustion reactions work?

a proton is transferred from a proton donor (acid) to a proton acceptor (base)

How do Acid-Base rxns work?

2 Na _(s) + Cl₂ _(g)→ 2 NaCl _(s)

Elemental sodium reacts with chlorine gas to produce sodium chloride.

2 Ca _(s) + O₂ _(g)→ 2 CaO _(s)

Solid calcium reacts with oxygen gas to form calcium oxide

2 C₃H₈ _(g) + O₂ _(g)→ CO₂ _(g) + H₂O _(l)

What is the balanced equation for the combustion of propane, C₃H₈?

1. Comprised of a positive and negative ions in a repeating, regular pattern

2. held together by strong ionic bonds

3. Solid at room temps.

4. hydration spheres created around ions when dissolved in water

What are the components of an ionic compound?

a homogenous mixture involving a substance (solute) being dissolved in a medium (solvent)

Define Solution

Water, H₂O!

What solvent do aqueous solutions have?

Use (aq) after the molecule’s name as a subscript

How do you notate that a compound has been dissolved in water?

1. comprised of stable, neutral molecules in which atoms are held together by covalent bonds

2. their state (s, l, g) depends on the strength of the inter-molecular bonds

3. When dissolved in water, they become hydrated

4. when dissolved in water, they might create ions, but it depends on if they react with water or not

What is a Molecular Compound?

Ionic	Molecular
metal + non-metal	2 non-metals
polyatomic atoms

Ionic vs. Molecular Compounds

Ionic

Ionic or Molecular?: Sodium chloride — NaCl

Ionic

Ionic or Molecular?: Magnesium sulfate — MgSO₄

Ionic

Ionic or Molecular?: Magnesium sulfate — MgSO₄

Ionic

Cation: Potassium (K)

Anion: permanganate (MnO₄)

Ionic or Molecular?: Potassium permanganate — KMnO₄.

Molecular

Ionic or Molecular?: Carbon dioxide — CO₂.

Molecular

Ionic or Molecular?: Sulfur hexafluoride — SF₆

Following the solubility rules, a precipitate will form as a solid

How do you know if a precipitate will form when two aqueous solutions mix?

products of rxn

Solubility Rules only apply to…

1. alkali metals (group 1) are soluble

2. ammonium salts (NH₄anion) are soluble

3. nitrates are soluble (ex. AgNO₃⁻)

4. Chlorides (Cl⁻), bromides (Br⁻) and iodides (I⁻) are soluble except for the chlorides, bromides and iodides of lead (Pb²⁺), mercury (Hg+ and Hg22+) and silver (Ag+). Example: ZnCl₂ is soluble. PbCl₂ is not soluble.

5. Sulfates are all soluble except for the sulfates of calcium, lead, silver, mercury, barium, strontium

6. Carbonates (CO₃²⁻), phosphates (PO₄³⁻), and sulfides (S²⁻) are insoluble except for:

   1. alkali salts (rule 1)

   2. ammonium (rule 2)

7. Hydroxides are insoluble except:

   1. fully soluble with alkalis (rule 1)

   2. slightly soluble

What are the rules of solubility?

proton (H⁺) donor

give proton to the base

According to Bronsted-Lowry, what are acids?

proton acceptors

According to Bronsted-Lowry, what are bases?

• proton donation rxn

• when an acid donates a proton from its possession to a base, who accpts the proton (H⁺)

What is an acid-base rxn? (Bronsted-Lowry definition)

1. pronated

2. hydronium, H₃O⁺

When an acid is dissolved in water, the water becomes ________. What forms in the water?

1. depronated

2. hydroxides released, OH⁻

When an base is dissolved in water, the water becomes ________. What happens in the water?

• by the amount of molecules reacting with the water

• strong = almost every/every molecule reacting with water

What determines if an acid is strong?

1. HCl - hydrochloric acid 

2. HBr - hydrobromic acid 

3. HI - hydroiodic acid 

4. HCl - perchloric acid 

5. HCl - perbromic acid 

6. HCl - periodic acid 

7. H₂SO₄ - sulfuric acid 

8. HNO₃ - hydrochloric acid 

What are the strong acids?

1. Binary Acids

2. Oxo Acids

What types of acids are present when talking about common strong acids?

• acids that contain H and another element, X

• general formula: HₙX

• the H is bonded directly to the X

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1. HCl - hydrochloric acid 

2. HBr - hydrobromic acid 

3. HI - hydroiodic acid 

What are Binary Acids? Which strong acids are Binary?

• acids that contain H, another element, X, and an O

• general formula: HₙXO_a

• the H is bonded directly to the O

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1. HCl - hydrochloric acid 

2. HBr - hydrobromic acid 

3. HI - hydroiodic acid 

What are Oxo Acids? Which strong acids are Oxo Acids?

1. group 1 hydroxides

   1. ex. LiOH, NaOH, KOH, RbOH

2. Group 2 hydroxides are only slightly soluble or sparingly soluble in water.

   1. ex. Mg(OH)₂, Ca(OH)₂, Sr(OH)₂, Ba(OH)₂

3. Hydride ions and oxide ions react with water producing hydroxide ions in solution

   1. hydride (H⁻)

   2. oxide ions (O²⁻)

What are some strong bases?

salt!

In a neutralization reaction, an acid and base react to form a ____.

water!

What is produced most times in an acid-base neutralization?

if a strong acid or base is present

What determines if a rxn goes to full completion?

HCl_(aq) + NaOH_(aq) → HCl_(aq) + H₂O_(l)

For a strong acid, HCl, and a strong base, NaOH, we get the following equation…

HF_(aq) + NaOH_(aq) → NaF_(aq) + H₂O_(l)

For a weak acid, HF, and a strong base, NaOH, we get the following equation:

HCl_(aq) + NH₃_(aq) → NH₄Cl_(aq)

For a weak base, NH₃, and a strong acid, HCl, we get the following equation: