Chemistry Blog
59 in-depth guides on chemistry concepts, study strategies, and step-by-step problem solving techniques.
How to Draw Lewis Structures: Step-by-Step Guide with Examples
A clear, step-by-step method for drawing Lewis structures for any molecule or ion, with worked examples and common pitfalls.
How to Balance Chemical Equations: 5 Methods That Work
Five reliable methods for balancing chemical equations, from simple inspection to algebraic approaches for complex reactions.
The Mole Concept Explained: From Avogadro to Stoichiometry
A practical explanation of the mole concept, Avogadro's number, molar mass, and how to convert between grams, moles, and particles.
VSEPR Theory: Molecular Geometry Step-by-Step (All 5 Shapes Explained)
How to use VSEPR theory to predict molecular shapes from Lewis structures, with all five electron geometries and their molecular shapes explained.
Dimensional Analysis in Chemistry: The Unit Conversion Method
Master dimensional analysis for chemistry. Learn how to set up conversion factors, chain conversions, and avoid unit errors in stoichiometry problems.
Organic Chemistry Naming: IUPAC Nomenclature Made Simple
A practical guide to IUPAC nomenclature for organic molecules, covering alkanes, alkenes, alkynes, and common functional groups.
How to Study Chemistry: Methods That Actually Work
Evidence-based study strategies specifically designed for chemistry, covering problem practice, concept mapping, active recall, and how to use AI tools effectively.
Chemistry Lab Safety: Rules, Equipment, and Common Mistakes
Essential chemistry lab safety rules covering PPE, chemical handling, equipment use, emergency procedures, and the most common safety mistakes students make.
ICE Tables Chemistry: Step-by-Step Equilibrium Setup (Kc, Ka, Kb)
How to set up Initial/Change/Equilibrium tables for Kc, Ka, and Kb problems with worked examples covering quadratic and small-x approximation methods.
Q vs K Chemistry: How to Predict Reaction Direction (Worked Examples)
How to use the reaction quotient and equilibrium constant to predict whether a reaction shifts left or right.
Calorimetry at Constant Pressure: Step-by-Step Problem Method
A clear workflow for solving coffee-cup calorimetry problems with q = mcΔT and sign conventions.
How to Calculate pH from Ka and Kb: Worked Weak Acid/Base Examples
Step-by-step method for calculating pH from Ka and Kb using ICE setup, with worked weak acid and weak base examples and the 5% approximation check.
Empirical vs Molecular Formula: 5-Step Method + Examples
Convert percent composition data into empirical and molecular formulas with a repeatable ratio method that reduces rounding errors.
Net Ionic Equations with Solubility Rules: Fast, Accurate Method
A structured method for writing molecular, complete ionic, and net ionic equations using core solubility rules.
Henderson-Hasselbalch Equation: Buffer pH Step-by-Step Guide
A practical method for buffer pH calculations, ratio setup, and common exam mistakes when using Henderson-Hasselbalch.
Oxidation Numbers in Chemistry: Rules, Tricks, and Worked Examples
Learn a reliable sequence for assigning oxidation numbers in compounds and ions, including exceptions and redox shortcuts.
Solubility Rules: Predict Precipitates with 7 Worked Examples
A concise framework for using solubility rules to predict precipitates and write accurate complete and net ionic equations.
What Is the Difference Between Ionic and Covalent Bonds?
A clear comparison of ionic and covalent bonding including how they form, their properties, and how to identify them from formulas.
How to Calculate Molarity (M = mol/L): Worked Examples + Dilution
Molarity calculation step-by-step using the M = moles/liters formula, with worked examples for unit conversions, dilution problems (M1V1 = M2V2), and common exam mistakes.
What Is Electronegativity and Why Does It Matter in Chemistry?
Understand electronegativity, how it trends across the periodic table, and why it determines bond polarity, molecular shape, and reactivity.
Ideal Gas Law (PV=nRT) and the Gas Laws: Worked Examples Explained
A complete guide to the gas laws — from the individual laws (Boyle's, Charles's, Gay-Lussac's, Avogadro's) to the combined gas law and the ideal gas law (PV = nRT). Covers derivations, unit pitfalls, worked problems, and when real gases deviate from ideal behavior.
Enthalpy vs Entropy vs Gibbs Free Energy: 8 Worked Examples
Thermodynamics answers the most fundamental question in chemistry: will this reaction happen spontaneously? This guide explains enthalpy (ΔH), entropy (ΔS), and Gibbs free energy (ΔG) from the ground up — what each one measures, how to calculate them, and how ΔG = ΔH - TΔS determines whether a reaction is spontaneous.
How to Balance Redox Reactions Using the Half-Reaction Method (Acidic and Basic Solutions)
Balancing redox reactions is one of the most challenging skills in general chemistry because you need to balance both atoms and charge simultaneously. The half-reaction method breaks this into manageable steps that work every time, in both acidic and basic solutions.
Rate Laws Explained: How to Find Reaction Order (Worked Examples)
A rate law expresses how the speed of a chemical reaction depends on the concentration of reactants, with each reactant raised to an experimentally determined power called the reaction order — you cannot determine reaction order from the balanced equation alone.
Organic Chemistry Functional Groups: Identification, Properties, and Reactivity Patterns
A functional group is a specific arrangement of atoms within a molecule that determines its chemical reactivity — learning to recognize functional groups is the single most important skill in organic chemistry because every reaction mechanism, naming convention, and physical property prediction depends on identifying which functional groups are present.
Acid-Base Titration: How to Do the Calculation, Pick the Right Indicator, and Read the Curve
A hands-on guide to acid-base titration covering the math behind equivalence point calculations, how to choose the right indicator, and how to interpret titration curves for strong acid-strong base and weak acid-strong base combinations.
How to Solve Stoichiometry Problems: Mole-to-Mole, Mass-to-Mass, and Limiting Reagent
A systematic walkthrough of stoichiometry problem solving covering the mole ratio method, mass-to-mass conversions, limiting reagent identification, and percent yield calculations with worked examples.
Intermolecular Forces Explained: London Dispersion, Dipole-Dipole, and Hydrogen Bonding
A thorough guide to the three types of intermolecular forces — how each one works at the molecular level, how to predict which forces a molecule experiences, and how IMFs explain boiling points, solubility, viscosity, and surface tension.
Galvanic vs Electrolytic Cells: How Electrochemistry Problems Work
A step-by-step guide to electrochemistry covering how galvanic (voltaic) cells generate electricity from spontaneous reactions, how electrolytic cells use electricity to drive non-spontaneous reactions, and how to solve cell potential and Nernst equation problems.
Electron Configuration and Quantum Numbers: How to Write Them and Why They Matter
A step-by-step guide to writing electron configurations and understanding quantum numbers — covering the aufbau principle, Hund's rule, the Pauli exclusion principle, shortcut notation, and common exceptions that exams love to test.
Colligative Properties: Boiling Point Elevation, Freezing Point Depression, and Osmotic Pressure
A clear guide to colligative properties — the physical properties of solutions that depend on the number of dissolved particles, not what those particles are — covering the math behind boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure.
Nuclear Chemistry: Radioactive Decay Types, Half-Life Calculations, and Nuclear Equations
A step-by-step guide to nuclear chemistry covering the four types of radioactive decay, how to write balanced nuclear equations, half-life calculations with worked examples, and the applications of nuclear chemistry from medicine to energy.
Periodic Table Trends: Atomic Radius, Ionization Energy, and Electron Affinity Explained
A clear guide to the three major periodic trends — atomic radius, ionization energy, and electron affinity — covering why each trend exists at the atomic level, how to predict values from position on the table, and the exceptions that exams love to test.
SN1, SN2, E1, E2: How to Choose the Right Mechanism Every Time
Four mechanisms, one decision. The SN1/SN2/E1/E2 problem is the most-tested topic in organic chemistry because it combines substrate structure, nucleophile strength, base strength, and solvent effects into a single question. Here is the decision framework that works.
How to Predict Products of Chemical Reactions: A Systematic Approach for Every Reaction Type
Given reactants, predict the products. It is the single most common question format in general chemistry. Instead of memorizing hundreds of reactions, use this systematic approach to classify the reaction type and predict what forms.
Mole Conversions Made Easy: Grams to Moles, Moles to Molecules, and Every Conversion Between
Mole conversions are the foundation of all quantitative chemistry — stoichiometry, concentration, gas laws, everything. If you can convert between grams, moles, and molecules, you can solve 80% of gen chem problems. Here is the method that never fails.
How to Calculate pH for Strong and Weak Acids and Bases: Formulas and Worked Examples
pH calculations follow different rules for strong vs weak acids and bases. Strong acids dissociate completely — the math is simple. Weak acids partially dissociate — you need Ka and an ICE table. Here is when to use each approach and how to avoid the mistakes that cost exam points.
How to Draw Resonance Structures: Rules, Steps, and Worked Examples
Resonance structures confuse students because the molecule does not actually flip between forms — it is a single hybrid. This guide covers the rules for drawing valid resonance structures, how to identify the major contributor, and how to apply resonance to real exam problems.
How to Find the Limiting Reagent and Calculate Theoretical Yield: Step-by-Step Method
Every limiting reagent problem uses the same method: convert both reactants to moles, compare to the mole ratio, and calculate from the one that runs out first. This guide walks through the method with worked examples covering every variation you will see on an exam.
Buffer Solutions: How to Prepare Them, Calculate pH, and Choose the Right Weak Acid/Base Pair
Buffer solutions resist changes in pH when small amounts of acid or base are added. This guide covers how buffers work, how to calculate the pH of a buffer using Henderson-Hasselbalch, how to prepare a buffer in the lab, and how to choose the right conjugate pair for your target pH.
Molecular Polarity and Dipole Moment: How to Determine If a Molecule Is Polar or Nonpolar
Whether a molecule is polar or nonpolar affects almost every chemical property — solubility, boiling point, intermolecular forces, and reactivity. This guide explains how to determine molecular polarity using VSEPR geometry, bond polarity, and vector addition of dipole moments, with the common molecules that trip students up.
Hybridization of Orbitals: sp, sp², sp³ Explained With Worked Examples
Orbital hybridization is one of the concepts gen chem students find most confusing because it seems arbitrary until you connect it to molecular geometry. This guide explains why hybridization exists, how to identify sp, sp², and sp³ hybridization from a Lewis structure, and how it connects to bond angles and molecular shape.
Le Chatelier's Principle: How Systems Respond to Stress With Worked Equilibrium Shift Examples
Le Chatelier's principle predicts how a chemical system at equilibrium responds when you change its conditions — concentration, pressure, volume, or temperature. This guide covers the principle with worked examples for each type of stress, including the common exam traps around inert gases and temperature changes for exothermic vs endothermic reactions.
How to Solve Dilution Problems: The M1V1 = M2V2 Formula With Worked Examples
Dilution problems ask how to make a less concentrated solution from a more concentrated one by adding solvent. The formula M1V1 = M2V2 is simple but students make consistent errors with units, concentration types, and applying the formula in reverse. This guide walks through the formula, worked examples, and the specific traps.
Solution Stoichiometry: How to Use Molarity in Chemical Reactions With Worked Examples
Solution stoichiometry combines two skills: stoichiometry (mole ratios from balanced equations) and molarity (moles per liter). When reactants are in solution, you calculate moles from M × V instead of grams ÷ molar mass. This guide covers the concept, the step-by-step method, worked examples for acid-base neutralization and precipitation reactions, and the common exam traps.
Ideal Gas Law Problems: PV = nRT Step-by-Step with Worked Examples
The ideal gas law (PV = nRT) is one of the most tested equations in general chemistry. This guide covers the equation, unit conversions, the correct value of R to use, and step-by-step solutions to the most common problem types.
Balancing Redox Reactions: Half-Reaction Method Step-by-Step Guide
Balancing redox reactions is one of the most tested topics in general chemistry and organic chemistry. This guide walks through the half-reaction method for both acidic and basic solutions, with worked examples and the specific steps that trip up students.
Hess's Law: How to Calculate Enthalpy Change with Worked Examples
Hess's law lets you calculate the enthalpy change for any reaction by combining known reaction enthalpies — no need to measure directly. Walk through the three main problem types with step-by-step solutions.
How to Assign R and S Configuration: CIP Rules with Worked Examples
Assigning R or S configuration to a chiral center is a core organic chemistry skill tested on every exam from gen chem to the MCAT. Master the CIP priority rules and the three-step assignment process with stepwise worked examples.
Molar Mass Calculation: Step-by-Step Worked Examples for Compounds, Hydrates, and Unknown Formulas
Molar mass is the bridge between grams and moles — the single most-used conversion in general chemistry. This guide walks through calculating molar mass for simple compounds, hydrates, ionic formulas, and unknown molecules from percent composition, with worked examples for every common exam scenario.
Beer-Lambert Law: Absorbance to Concentration Worked Examples (Spectrophotometry for Chemistry Students)
Beer-Lambert law connects absorbance to concentration through a linear equation — A = εbc. This guide walks through worked examples for calibration curves, unknown concentration determination, and the assumptions that break down in real lab measurements.
Arrhenius Equation: Activation Energy and Rate Constants (Worked Examples for Chemistry Students)
The Arrhenius equation connects temperature, activation energy, and reaction rate — one of the most-tested concepts in general and physical chemistry. This guide walks through the formula in both integrated and two-point forms, with worked examples for finding activation energy, predicting rate changes, and interpreting Arrhenius plots.
Polyprotic Acid Titration Curves: Ka1, Ka2, Ka3 and Stepwise Equivalence Points (Worked Examples)
Polyprotic acids like H₃PO₄ and H₂SO₃ donate protons stepwise, producing titration curves with multiple equivalence points and pH plateaus at each half-equivalence point. This guide walks through drawing and interpreting the curves, calculating pH at each point, and using them to identify unknown polyprotic acids.
Alkene Addition Reactions: Markovnikov and Anti-Markovnikov Worked Examples
Alkene addition reactions follow predictable rules once you understand carbocation stability. This guide walks through Markovnikov vs anti-Markovnikov additions with mechanism-level worked examples.
NMR Splitting Patterns: The n+1 Rule and Worked Interpretations
H-NMR splitting patterns tell you how many neighbors each proton has. This guide walks through the n+1 rule, chemical shift ranges, integration, and complete spectra interpretation with worked examples.
Significant Figures and Error Propagation: Worked Examples
Significant figures track measurement precision; error propagation extends that idea to calculated quantities. This guide walks through the rules with 7 worked examples — addition, multiplication, mixed operations, log/exp functions, and lab-relevant uncertainty propagation.
Carbocation Stability Ranking and Rearrangements: Worked Examples
Carbocation stability determines reaction outcome in every SN1, E1, and electrophilic addition reaction. This guide ranks carbocations from least to most stable and walks through 6 worked rearrangement examples (1,2-hydride and 1,2-methyl shifts).
Rate Law Determination by the Method of Initial Rates: Worked Examples
How to determine the rate law (orders, rate constant, units) for a reaction from initial-rate experimental data. Step-by-step worked examples for first-order, second-order, and mixed-order kinetics.
Nernst Equation: Galvanic Cell EMF Under Non-Standard Conditions (Worked Examples)
How to use the Nernst equation to calculate cell potential when concentrations are not 1 M. Step-by-step worked examples for concentration cells, pH dependence, and equilibrium prediction.