Lecture Notes: Types of Chemical Reactions and Key Concepts

Flashcards covering main reaction types, patterns, real-world examples, signs of reactions, and safety considerations from the notes.

General equation for combustion

O2 + fuel → CO2 + H2O + energy

Synthesis reaction pattern

2 reactants → 1 product (A + B → AB)

Decomposition reaction pattern

1 reactant → 2 products (AB → A + B)

Single displacement pattern

A + BC → AC + B

Double displacement pattern

AB + CD → AD + CB

How can you tell a chemical reaction occurred in the described demo?

Bubbles/foam from oxygen release and a temperature rise.

The reaction type in the hydrogen peroxide demo

Decomposition (H2O2 → H2O + O2).

Word equation for hydrogen peroxide decomposition

Hydrogen peroxide → water + oxygen

Word equation example for synthesis (Mg and O2)

Magnesium + oxygen → magnesium oxide

Signs of combustion

Heat, light, flames; gases such as CO2 and water vapor.

Why is oxygen needed in combustion?

Oxygen reacts with the fuel to release energy.

Complete combustion products

CO2 and H2O when there is enough oxygen.

Incomplete combustion products

CO and soot when oxygen is insufficient.

Real-world examples of combustion

Burning wood, petrol in engines, or a candle flame.

What happens in a synthesis reaction?

Two reactants combine to form one product.

Real-world synthesis example (rusting)

Iron + oxygen → iron oxide.

Why is synthesis opposite to decomposition?

Synthesis builds one substance from two; decomposition breaks one into two or more.

What happens in a decomposition reaction?

One reactant breaks down into two or more products.

Decomposition pattern

AB → A + B

Word equation for hydrogen peroxide decomposition

Hydrogen peroxide → water + oxygen

How can you tell a reaction is decomposition from a word equation?

One reactant splits into simpler substances (two products).

Real-world use of decomposition

Hydrogen peroxide decomposing in wound cleaning; baking soda decomposing in baking.

What is a single displacement reaction?

One element replaces another in a compound.

Single displacement pattern

A + BC → AC + B

Example of single displacement

Zinc + hydrochloric acid → zinc chloride + hydrogen gas

How can you tell from a word equation that a reaction is single displacement?

You start with one element + one compound and end with a new compound + a different element.

Why does one element get replaced in single displacement?

Because it is more reactive and pushes the other element out.

What is a double displacement reaction?

Two compounds swap ions to form two new compounds.

Double displacement pattern

AB + CD → AD + CB

Example of double displacement

Silver nitrate + sodium chloride → silver chloride + sodium nitrate

What often forms in a double displacement reaction?

A precipitate, water, or a gas.

Difference between single and double displacement

Single = one element replaces another; Double = two compounds swap ions.

Elephant's toothpaste chemical equation

2 H2O2 → 2 H2O + O2

Combustion reactants and products

Reactants: O2 and fuel; Products: CO2, H2O, and energy

Distinct signs of combustion

Heat, light, flames, CO2 and water vapor.