C3 - Chemical Reactions

Chemical symbol

The abbreviation for each element, with the first letter capitalized and the second letter (if present) lowercase, found on the periodic table

Ion

An atom or molecule with a net positive or negative charge due to losing or gaining electrons

Polyatomic ions

Ions containing two or more atoms. Examples include hydroxide and sulfate

Diatomic elements

Elements that naturally exist as molecules with two atoms, written with a subscript. Examples: H₂, N₂, O₂

Covalent bond

Bond between two atoms sharing electron pairs, typically between nonmetal atoms

Ionic bond

Bond formed by electrostatic attraction between ions, leading to electron transfer

Reactants

Substances consumed in a chemical reaction, written on the left side of the arrow

Products

Substances produced in a chemical reaction, written on the right side of the arrow

Electrostatic attraction

Attraction between charged particles affecting atomic structure and interactions

Mole

Unit to measure particles like atoms and molecules

Molar mass

Mass of one mole of a substance, calculated using atomic masses of atoms present

Chemical Reaction

Process where substances (reactants) change to form different substances (products)

Chemical equation

Symbolic representation of a chemical reaction showing reactants and products

Balanced chemical equation

Equation with proper ratios of reactants and products, same elements on both sides

Stoichiometry

Ratios of reactants and products in a balanced chemical equation, like mole ratio

Law of Conservation of Mass

Mass cannot be created or destroyed.

Half equation

An equation that shows the change that one substance undergoes in a chemical reaction

Acid

A substance that produces an acidic solution in water by releasing more hydrogen ions (H⁺) than hydroxide ions (OH^-)

Alkali

A substance that produces an alkaline solution in water by releasing more hydroxide ions than hydrogen ions when dissolved

pH Scale

A scale that measures the acidity or alkalinity of a solution

Neutralization Reaction

A reaction involving an acid and a base or alkali that results in the formation of a salt and water

Electrolysis

The process of breaking down electrolytes using an electric current to produce free ions attracted to oppositely charged electrodes

Cations

Positively charged ions that move towards the cathode during electrolysis

Anions

Negatively charged ions that move towards the anode during electrolysis

Electroplating

The process of using electrolysis to deposit a thin layer of metal onto another metal object, often used for protection against corrosion or purification purposes

Endothermic reaction

A reaction in which more energy is used to break down the reactants than is used to form the products

Exothermic reaction

A reaction that requires more energy to form products than it uses to break down reactants

Activation energy

The minimum amount of energy required for a reaction to occur

Bond energy

The amount of energy necessary to break one mole of a particular covalent bond

Oxidation-Reduction reaction

A reaction in which electrons are transferred between chemical species

Oxidation

the process of a substance gaining oxygen, or losing electrons, during a chemical reaction

Reduction

the process of a substance losing oxygen, or gaining electrons, during a chemical reaction

Strong acids

Acids that completely dissociate in solution

Weak acids

Acids that only partially dissociate in solution

State symbols

Symbols sometimes included in chemical equations that indicate the physical state of each component

Electricity

The flow of electrons

Oxidation number

The number of electrons an atom loses or gains in order to form a bond with another atom

Complete ionic equation

An equation that shows all the ions involved in a chemical reaction

Net ionic equation

An ionic equation that shows the reacting ions and the resulting precipitate(s), but does not include spectator ions

Spectator ions

Ions present that do not directly participate in the reaction