12 articles
Moles & Chemical Calculations
The mole, molar mass, formulas, yields and every calculation type you meet in a chemistry course.
What Is Molar Mass, and How Do You Calculate It?
What molar mass actually means, why it's central to stoichiometry, and how to calculate it for any formula by hand — plus when to just use a calculator.
Density in Chemistry: Formula, Units and Worked Examples
What density is, how to calculate it and rearrange the formula, unit conversions, density of gases, and how density identifies substances — with worked examples.
Percent Composition: How to Calculate It and What It Tells You
How to find the mass percent of each element in a compound, worked examples from water to caffeine, and how chemists use percent composition in the real world.
Avogadro's Number: What It Is and Why It's 6.022 × 10²³
What Avogadro's number means, where the value 6.022 × 10²³ comes from, how it was measured, why it became exact in 2019, and how big it really is.
How to Convert Grams to Moles (and Moles to Grams)
The one-step method for converting between grams and moles, worked examples for elements, compounds and hydrates, and the mistakes that cost students marks.
Titration Calculations Step by Step
A reliable method for every titration calculation: 1:1 and 2:1 ratios, diluted samples, finding a molar mass, percentage purity and water of crystallisation, with six fully worked examples.
Limiting Reagent: How to Find It (With Worked Examples)
What a limiting reagent is, the reliable method for finding it, how to calculate theoretical yield and leftover excess reactant, and why the smallest mass isn't always limiting.
Percent Yield Explained: Theoretical vs. Actual Yield
How to calculate theoretical yield and percent yield, worked examples, why real yields fall short of 100%, and what it means when a yield comes out above 100%.
Empirical vs. Molecular Formula: What's the Difference and How to Find Each
What empirical and molecular formulas are, a step-by-step method for finding both from lab data, and how to handle ratios like 1.5 and 1.33 correctly.
Stoichiometry Step by Step: The Mole Map Method
A beginner-friendly method for solving any stoichiometry problem — mass to mass, mass to moles, gases and solutions — built around one simple roadmap.
Hydrates Explained: Water of Crystallization and How to Calculate It
What hydrates are, how to read formulas like CuSO₄·5H₂O, how to calculate their molar mass and percent water, and how to find the formula of an unknown hydrate by heating.
Back Titration Calculations Explained
What a back titration is, when to use one, and a step-by-step method for the calculations, with five worked examples: limestone, antacids, ammonia from ammonium salts, aspirin and chloride by Volhard's method.