Chemistry 11 - Unit 2: Reactions

Evidence of Chemical Reactions

1) Change in Color

2) Energy is released or absorbed

3) Gas is produced

4) Precipitate is formed

5) Change in odour

Atoms in Chemical Reactions

Never created or destroyed.

Are only rearranged, broken down, or form new bonds.

Law of Conservation of Mass

Total mass of reactants = Total mass of products

Catalyst

Substance that makes a chemical reaction occur faster without being in the reaction itself

Synthesis

2 or more REACTANTS combine to form one LARGER / COMPLEX PRODUCT

Decomposition

A LARGER / MORE COMPLEX REACTANT that breaks down into 2 OR MORE SIMPLER PRODUCTS. Most decomposition reactions require energy (Heat, electricity)

Single displacement

One element displaces another element in a compound, producing a new element & compound

Metal / Halogen Activity Series

The element has to be above the other element in the compound or else there will be no reaction.

Further apart means more vigorous displacement.

Double Displacement

Elements in 2 compounds displace each other, producing 2 new compounds

Solubility Table

The combination of cations and anion that are very/slightly soluble

PRECIPITATES form…

when the new compound is only slightly soluble in the liquid

Solubility

The amount of solute that dissolves in a given amount of solvent at a specific temperature: Highly or Slightly Soluble (Precipitate)

Solute

The substance that dissolves (Salt)

Solvent

The substance that dissolves the solute (Water)

Soluble

1g > of solute will dissolve in 100mL of water at room temperature

"Insoluble"

1g < of solute will dissolve in 100mL of water at room temperature.

Ion Charge & Solubility

Small ion CHARGE = Less FORCE = SOLUBLE

Large ion CHARGE = Higher FORCE = INSOLUBLE

Ion Size + Solubility

Smaller ions = More concentrated = Harder to separate = INSOLUBLE

Larger ions = Less concentrated = Easier to separate = SOLUBLE

Temperature

A measurement of the average kinetic energy of the particle in a substance.

Temperature & Chemical Reactions

In chemical reactions, particle can only react when they collide with each other.

Increasing temperature can increase the frequency of the particle colliding.

Combustion

A chemical reaction in which fuel burns in oxygen.

FUEL: Propane, coal, gasoline, oxygen, HYDROCARBONS.

ALWAYS release thermal energy & often light

COMMON products include carbon dioxide, water, and carbon monoxide.

Complete Combustion

Hydrocarbon burn in LOTS of OXYGEN → Carbon dioxide, Water, Energy

Incomplete Combustion

Hydrocarbon burn in LIMITED Oxygen → Carbon dioxide, carbon monoxide, soot, water, energy.

Negatives of Incomplete Combustion

Car idling due to lower operating temperature.

Soot particle (Loose carbon) can be toxic and irritate respiratory tissues

Carbon monoxide (silent killer) can prevent hemoglobin from picking up O2

Dissociation

When ionic compounds dissolve to produce ions. Water molecules pull apart the ionic crystal.

Water = Positive hydrogen + Negative Oxygen

Ion-Dipole Force

Polar ends of the water molecule attract the positive and negative ions within the crystal.

Aqueous solutions are created when ionic compounds are dissolved in water.

Double Displacement reactions occur when…

Precipitate is formed.

Formation of gas (CO2, H2S, SO2).

Formation of water (Neutralization)

Spectator Ions

ions that do not participate in a reaction

Oxides

Any compound of any element combined with oxygen (oxides can create acids/bases)

Acids

Produces HYDROGEN IONS (H) in water

Acidic Oxides

Oxide that form an acidic solution when dissolved in water (non-metallic oxide)

1) CARBON DIOXIDE + WATER = CARBONIC ACID: Shifts in ocean acidity

2) NITROGEN OXIDE + WATER = Acidic rain

3) SULFUR OXIDE + WATER = Acidic rain

Bases

Produces HYDROGEN IONS (OH) in water

Basic Oxides

Oxides that form a basic solution when dissolved in water (metallic oxide)

1) SODIUM OXIDE + WATER = Sodium Hydroxide: Drain cleaner

2) CALCIUM OXIDE + WATER = Calcium Hydroxide: Neutralizes acid spills

Neutralization

Can happen when mixing an Acid with either Hydroxide or Carbonate (bases)

Reactions in Industry: Rockets

Combustion / Synthesis Reaction:

To launch items into space. 1) Hydrogen Gas + Oxygen Gas = Water Vapour 2) Aluminum + Oxygen Gas = Aluminum Oxide

Reactions in Industry: Gas Scrubbers

Synthesis / Neutralization:

To remove unwanted pollutants from waste gases; The scrubber absorb the pollutant gasses (HCL)

1) Sulfur Dioxide Gas + Oxygen Gas = Sulfur Trioxide

2) Sulfur Trioxide + Water Vapour = Sulfuric Acid

Reactions in Industry: Smelting Iron Ore

Synthesis / Decomposition: To isolate iron from iron ore by heating the ore at high temperatures.

1) Carbon + Oxygen = Carbon Monoxide

2) Carbon monoxide + Iron Ore = Iron + Carbon Dioxide

Neutralization Reactions in Industry: Heartburn

Stomach acid irritates the esophagus, while the antacids neutralize the reaction, minimizing irritation.

HCL (acid) + Aluminum Hydroxide (base) → H2O + AlCl3

Neutralization Reactions in Industry: Baking

The reaction between the tartaric acid and baking soda produces carbon dioxide bubbles that are trapped within the dough, allowing the dough to rise.

Tartaric Acid (Acid) + Baking Soda (Base) → Na2C4H4O6 + H2O + CO2

Synthesis #1

Metal + Non-Metal = Ionic Bond

Synthesis #2

Metal / Non-Metal + Oxygen = Oxide

Synthesis #3

Metal Oxide + Water = Base (OH)

Synthesis #4

Non-Metal Oxide + Water = Acid (H#CO#)

Decomposition #1

Water = Hydrogen + Oxygen

Decomposition #2: Carbonates

Metal Carbonate = Metal Oxide + Carbon Dioxide

Decomposition #3: Chlorates

Metal Chlorate = Metal Chloride + Oxygen

Single Displacement #1

Metal replaces Metal

Single Displacement #2

Non-metal replaces Non-metal

Double Displacement #1

Like elements exchange places to form one precipitate (S) and one solution (aq)

Double Displacement #2: Neutralization Reactions

Acid (H) + Base (OH) = Ionic Salt + Water

Double Displacement #3: Gas Production

1) H2S. 2) H2CO3 = H2O + CO2. 3) H2SO3 = H2O + SO2

Fires involving reactive metals; Why is pouring sand on the fire better than attempting to use a fire extinguisher?

Sand smothers the fire by cutting off the oxygen supply.

Why would individuals choose to replace lead pipes with copper ones?

Copper is less reactive then lead, as seen on the Reactivity Series