When you boil water for tea or light a candle, heat moves between the system and its surroundings. This exchange is explained by enthalpy, a way to measure the total heat content of a system. Chemists use the enthalpy formula, $H = U + PV$, to calculate heat changes in reactions or phase transitions. In …

When you buy eggs, you count them in dozens because dealing with each egg individually would be inefficient. Chemists face a similar challenge when working with atoms and molecules, which are far too small to count one by one. To solve this, they use a unit called the mole, which represents $6.022 \times 10^{23}$ particles. …

When carbon dioxide ($CO_2$) forms its linear shape or methane ($CH_4$) adopts a tetrahedral structure, the explanation is hybridization. Hybridization combines atomic orbitals into arranged hybrid orbitals to maximize bonding efficiency and minimize electron repulsion. We will explain hybridization step-by-step. You’ll learn how to identify the type of hybridization (sp, sp², sp³), connect it to …

Chemical bonds are like the glue that holds atoms together, forming the wide variety of substances we see around us. Getting a good grasp of these bonds is important for high school students to understand basic and more advanced chemistry ideas. This guide will explore different types of chemical bonds, how they form, and why …

When salt dissolves in water, it forms a clear solution, but oil and water refuse to mix. These everyday examples reveal how solvents interact with different substances. A solvent dissolves a solute to create a solution. In this guide, you’ll learn about solvents, including polar, nonpolar, and organic types and their unique chemistry properties. Solvents: …

Carbon forms the basis of millions of compounds, from the graphite in your pencil to the sugar in your food. Its ability to bond in countless ways makes it unmatched in chemistry. In this study guide, we’ll explore carbon’s atomic structure, carbon allotropes like diamond and graphite, and how it forms bonds in organic and …

Water, known chemically as $H_2O$, is an example of a molecule—a combination of atoms bonded to form a stable unit. Molecules are found everywhere—from the oxygen ($O_2$) in the atmosphere to the glucose ($C_6H_{12}O_6$) that fuels our cells—making them central to chemistry and life itself. We’ll start by looking at what a molecule is and …

A substitution is a chemical reaction that occurs when one atom or group in a molecule is swapped with another. Substitutions help create medicines, polymers, and other compounds we use daily. Certain antibiotics are made by using substitution reactions to adjust chemical structures. In this online textbook, you’ll learn about the main types of substitution—nucleophilic, …

Did you know that aldehydes are responsible for the distinctive smell of almonds? They are also preservatives found in many products. Due to their characteristic structure and reactivity, aldehydes such as acetic aldehyde and formaldehyde are used in flavourings, fragrances and even in important biological cycles. Our study guide presents what makes aldehydes unique, including …