Chemistry Revision

Yield

The amount of product obtained in a chemical reaction, often expressed as a percentage of the theoretical maximum.

Basic

A chemical substance that reacts with acids to form salts and water, and it typically has a pH greater than 7. It can accept protons or donate electron pairs.

Oxide

A compound formed when oxygen reacts with another element, typically involving the combination of oxygen with metals or nonmetals.

Combusted

When a substance reacts with oxygen to produce heat and light, often resulting in new products such as gases or ash. Can be complete or incomplete depending on amount of oxygen given.

Transition Metal

Also called transition elements. Are primarily found in Groups 3 through 12 of the periodic table and occupy the d-block. A transition metal is defined as an element that forms at least one ion with a partially filled d-subshell.

Melting Point

The temperature at which a solid turns into a liquid, where both phases coexist in equilibrium.

Ductility

A material’s ability to undergo significant plastic deformation under tensile stress without breaking, allowing it to be stretched or drawn into a wire.

Electrical Conductivity

The ability of a material to allow the flow of electric charge, typically enabled in metals by the presence of delocalised electrons.

Acid Rain

Precipitation that contains dissolved acidic components, primarily sulfuric and nitric acids, formed from atmospheric reactions of sulfur dioxide and nitrogen oxides.

Fossil Fuels

Carbon-based energy resources formed from the remains of ancient organisms over millions of years, and their combustion releases energy along with greenhouse gases.

Sulfur Dioxide (SO₂)

A colorless gas produced by burning sulfur-containing fuels, which reacts in the atmosphere to form acids contributing to environmental pollution.

Nitrogen dioxide (SO₂)

A reddish-brown toxic gas formed during high-temperature combustion, playing a major role in air pollution and acid rain formation.

Ion

An atom or group of atoms that has gained or lost one or more electrons, resulting in a net positive or negative electrical charge.

Avogadro’s Number

The constant 6.02×10²³ representing the number of particles (atoms, molecules, or ions) in one mole of a substance.

D-block Element

A chemical element found in the central section of the periodic table, characterized by having partially filled d-orbitals in at least one oxidation state.

Periodic Table

A systematic arrangement of chemical elements in order of increasing atomic number, designed to show recurring patterns in chemical properties.

Ethanol

Also known as ethyl alcohol, is a colorless, volatile liquid widely used in beverages, industrial applications, and as a fuel.

Complete Combustion

Occurs when a reactive reacts with excess oxygen to produce carbon dioxide and water, releasing energy as heat.

Theoretical Yield

The maximum amount of product that can be predicted from a chemical reaction based on stoichiometric calculations, assuming no losses.

Limiting Reagent

The reactant that is completely consumed first in a chemical reaction, thereby determining the maximum amount of product formed.

Coefficient

The relative number of moles or molecules of each substance involved in the reaction.

Collision

Reacting particles come into contact, and only those with sufficient energy and proper orientation lead to a successful chemical reaction.

Endothermic

A chemical process that absorbs energy from its surroundings, often resulting in a temperature decrease of the surroundings.

Exothermic

A chemical process that releases energy to its surroundings, usually in the form of heat, causing a temperature increase.