VerChem is a free chemistry platform offering deterministic calculators, a 2D structure editor with substructure and similarity search, spectroscopy and lab-safety references, an interactive periodic table with all 118 elements, and a database of 1,311 compounds. Published element references include IUPAC and NIST. Built for students, chemists, and engineers.

Is VerChem free to use?

Yes. The chemistry tools are free to use, with no per-calculation charge and no paid tier gating the chemistry itself.

How accurate is VerChem data?

VerChem cites published reference sources: standard atomic weights are based on the IUPAC 2021 table, while selected physical properties cite NIST and the CRC Handbook. VerChem is not certified by those organizations, and property coverage varies by element.

What calculators does VerChem offer?

VerChem offers 8 chemistry calculators: Molar Mass, Equation Balancer, Stoichiometry (8 modes), pH Calculator (11 modes), Gas Laws (9 modes including Van der Waals), Thermodynamics, Chemical Kinetics, and Electrochemistry. Plus interactive tools: 3D Molecular Viewer, Lewis Structures, VSEPR Geometry, and a table covering all 118 elements.

How do I calculate molar mass?

Enter a supported chemical formula (e.g., H2SO4, NaCl, C6H12O6) into the Molar Mass Calculator. It calculates molar mass by summing standard atomic weights × subscripts. For H2O: (2 × 1.008) + (1 × 15.999) = 18.015 g/mol. The standard atomic weights are based on the IUPAC 2021 table.

What is the Ideal Gas Law formula?

The Ideal Gas Law is PV = nRT, where P = pressure, V = volume, n = moles of gas, R = gas constant (8.314 J/mol·K or 0.0821 L·atm/mol·K), and T = temperature in Kelvin. VerChem Gas Laws Calculator supports 9 modes including Combined Gas Law and Van der Waals equation.

How do I calculate pH from concentration?

pH = -log[H+]. For a 0.01 M HCl solution: pH = -log(0.01) = 2. For bases, calculate pOH first, then pH = 14 - pOH. VerChem pH Calculator handles strong/weak acids and bases, buffer solutions, and shows visual pH scale.

How many elements are in the periodic table?

There are 118 confirmed elements. Elements 1-94 occur naturally (though some like Technetium and Promethium are extremely rare). Elements 95-118 are synthetic, created in laboratories. The latest additions (Nihonium, Moscovium, Tennessine, Oganesson) were confirmed by IUPAC in 2016.

What are rare earth elements?

Rare earth elements include 17 elements: Scandium (Sc), Yttrium (Y), and the 15 Lanthanides (La-Lu: Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium). Despite the name, most are not rare but are difficult to separate from each other.

What is a limiting reagent?

A limiting reagent is the reactant that is completely consumed first in a chemical reaction, determining the maximum amount of product that can be formed. VerChem Stoichiometry Calculator identifies the limiting reagent and calculates theoretical yield, actual yield, and percent yield.

How do I convert moles to grams?

Mass (g) = Moles × Molar Mass (g/mol). For example, 2 moles of water: 2 mol × 18.015 g/mol = 36.03 g. To convert grams to moles, divide: Moles = Mass / Molar Mass.

How is VerChem different from asking an AI chatbot for a chemistry calculation?

VerChem computes with deterministic engines rather than a language model. The same input always produces the same output. An optional Verified Answer Card records the exact inputs, semantic engine release, output, textbook citation, AI explanation, and an Ed25519 compact JWS covering them so the engine fields can be replayed and compared later. Anyone can verify that JWS independently against VerChem's published public key instead of trusting a server-reported validity result. Signature integrity and current-engine agreement are reported separately; cards from replaced releases are marked superseded or corrected instead of current VERIFIED. A chatbot writes its answer as text: it can vary between runs and leaves no record to re-check.

Is a VerChem result guaranteed to be correct?

It is reproducible, not infallible. A VerChem calculation is deterministic — identical inputs always give identical output — and cites published element references including IUPAC and NIST. Required physical inputs such as solution density or a reaction-specific equivalents factor must be supplied; calculations that need a missing value are rejected rather than guessed. Any listed assumptions describe the declared model scope. Verified Answer Cards are tamper-evident: any later edit breaks the signature. That signature proves the signed record was not altered; current validity is a separate replay check, and neither property proves the chemistry model applies to your situation.

How do you balance a chemical equation?

To balance a chemical equation: 1) Write the unbalanced equation, 2) Count atoms of each element on both sides, 3) Add coefficients to balance atoms, starting with the most complex molecule, 4) Verify all atoms are balanced.

Why must chemical equations be balanced?

Chemical equations must be balanced to satisfy the Law of Conservation of Mass, which states that matter cannot be created or destroyed. The number of atoms of each element must be the same on both sides of the equation.

All tools

Free online tool · no sign-up required

Chemical Equation Balancer

Balance molecular chemical equations instantly. Perfect for students, teachers, and chemists. Free, no sign-up, unlimited use.

Enter Your Chemical Equation

Press Enter ↵

Try These Examples

Click any equation below to balance it instantly

How to Balance Chemical Equations

Matrix algebra and Gaussian elimination balance molecular equations in milliseconds, then every result is re-checked for atom conservation

Step 1

Enter Equation

Type your unbalanced chemical equation using standard notation (e.g., H2 + O2 -> H2O)

Step 2

Parse & Analyze

Our system identifies all elements and counts atoms on both sides of the equation

Step 3

Calculate Coefficients

Advanced algorithms find the smallest whole number coefficients that balance the equation

Step 4

Verify & Display

We verify atom counts match and show you the balanced equation with detailed breakdown

Types of Chemical Reactions

Our balancer automatically identifies and labels reaction types

Synthesis

A + B → AB

Two substances combine to form one product

Decomposition

AB → A + B

One compound breaks into simpler substances

Combustion

CₓHᵧ + O₂ → CO₂ + H₂O

Rapid reaction with oxygen producing heat

Redox

Oxidation + Reduction

Electron transfer between species

Why Choose VerChem Equation Balancer?

Lightning Fast

Balance equations in milliseconds using advanced algorithms

Atom-Count Verified

Every balanced equation is re-checked for atom conservation, and every symbol is validated against the periodic table

Works Everywhere

Use on any device - desktop, tablet, or mobile

Completely Free

No sign-up, no limits, no hidden costs. Forever free!

Molecular Reactions

Synthesis, decomposition, combustion and redox written in molecular form

Educational

Shows step-by-step breakdown for learning

Frequently Asked Questions

How do I balance a chemical equation?+

Simply enter your unbalanced equation using the format "Reactants -> Products" (e.g., H2 + O2 -> H2O). Use element symbols with subscripts as numbers (H2O, not H₂O). Our calculator will instantly provide the balanced equation with correct coefficients.

What is a balanced chemical equation?+

A balanced chemical equation has equal numbers of each type of atom on both sides of the reaction arrow. This follows the Law of Conservation of Mass - matter cannot be created or destroyed in a chemical reaction.

Can this balance redox equations?+

Yes, when they are written in molecular form — for example KMnO4 + HCl -> KCl + MnCl2 + H2O + Cl2 balances correctly. Ionic half-equations carrying charges (MnO4⁻, Cr2O7²⁻, Fe³⁺) are rejected rather than guessed at, because balancing them correctly requires charge conservation, which this engine does not do yet. Coefficients up to 20 are supported.

Is this calculator free to use?+

Absolutely! VerChem Equation Balancer is 100% free with no usage limits. No sign-up required. Use it as many times as you need for homework, exams, or research.

How is a balanced result checked?+

The balancer uses matrix algebra (Gaussian elimination) with an optimised search, then verifies atom conservation on both sides and validates every symbol against the periodic table. A result that fails either check is reported as unbalanced rather than returned as an answer.

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Stoichiometry Calculator →Periodic Table →

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