Molar Mass Lab
Molar mass calculator and chemistry learning platform
Calculate molar mass from any chemical formula, then explore clear explanations, properties, reactions, and practice for the compounds you study most.
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Explore detailed molar mass calculations, physical and chemical properties, reactions, applications, and educational explanations for commonly studied chemical compounds.
Sodium Chloride
NaCl · 58.44 g/mol
Sodium chloride (NaCl) is an ionic compound with molar mass 58.44 g/mol, composed of Na⁺ (22.99 g/mol) and Cl⁻ (35.45 g/mol) in a 1:1 ratio. It crystallizes in a face-centered cubic lattice where each ion is octahedrally coordinated by six counterions, giving the familiar cubic cleavage of halite mineral samples. NaCl is essential for human physiology: sodium ions regulate extracellular fluid volume and nerve action potentials, while chloride accompanies sodium as the dominant electrolyte in blood plasma (~145 mM Na⁺, ~110 mM Cl⁻). The compound dissolves readily in water with ΔH_soln slightly endothermic (+3.9 kJ/mol) because the entropy gain from ion dispersal outweighs the lattice energy cost. Seawater averages about 3.5% NaCl by mass, and vast underground deposits of evaporite minerals record ancient enclosed seas that dried through geological time.
BaseSodium Hydroxide
NaOH · 40.00 g/mol
Sodium hydroxide (NaOH) is a strong base with molar mass 40.00 g/mol (Na 22.99 + O 16.00 + H 1.008). It dissociates completely in water to Na⁺ and OH⁻, giving pH values above 13 for concentrated solutions. NaOH is hygroscopic and deliquescent — it absorbs moisture from air until dissolving — and reacts exothermically with water (ΔH ≈ −44 kJ/mol dissolution). NaOH is produced at massive scale by the chlor-alkali process alongside chlorine and hydrogen from brine electrolysis. Its ability to saponify triglycerides (breaking ester bonds to form soap and glycerol) has made it central to soap manufacturing for centuries. In chemistry education, NaOH is the standard strong base for titrations against HCl and for adjusting pH in countless reactions.
InorganicWater
H₂O · 18.02 g/mol
Water (H₂O) is the most abundant compound on Earth's surface and the universal solvent in biological and chemical systems. Its molar mass of 18.015 g/mol arises from two hydrogen atoms (1.008 g/mol each) bonded to one oxygen atom (16.00 g/mol). Unlike most substances, liquid water reaches maximum density at 4 °C rather than at its freezing point, a consequence of hydrogen-bond-driven tetrahedral ordering that expands the crystal lattice when ice forms. The bent molecular geometry (104.5° bond angle) and high electronegativity difference between O and H give water a dipole moment of 1.85 D, enabling extensive hydrogen bonding. This network explains water's unusually high boiling point (100 °C) compared with analogues like H₂S (−60 °C) and its ability to dissolve ionic and polar substances through ion–dipole and dipole–dipole interactions. Water's behavior cannot be understood from its simple three-atom formula alone; nearly every one of its "anomalous" properties — high heat capacity, high surface tension, expansion on freezing, and unusually wide liquid range — traces back to the cooperative hydrogen-bonded network that forms and reforms roughly a trillion times per second in liquid water. This network gives water an outsized role in planetary climate regulation, biological chemistry, and geology, from buffering coastal temperatures to enabling the folding of proteins and the flow of glaciers.
GasCarbon Dioxide
CO₂ · 44.01 g/mol
Carbon dioxide (CO₂) is a linear triatomic molecule with molar mass 44.01 g/mol, formed from one carbon atom (12.01 g/mol) and two oxygen atoms. At standard temperature and pressure it is an invisible, odorless gas denser than air (ρ ≈ 1.98 g/L vs. air ~1.29 g/L), which is why it accumulates in low-lying areas and can displace breathable air in confined spaces. CO₂ plays a central role in Earth's carbon cycle. Plants fix atmospheric CO₂ into carbohydrates via photosynthesis, while respiration, combustion, and volcanic outgassing return it to the atmosphere. Since the Industrial Revolution, fossil fuel burning has raised atmospheric CO₂ from roughly 280 ppm to over 420 ppm, driving radiative forcing through the greenhouse effect: CO₂ absorbs infrared radiation emitted by Earth's surface, trapping thermal energy in the troposphere. Because CO₂ is both a natural biogeochemical participant and the dominant anthropogenic greenhouse gas, it occupies a unique dual role in chemistry education: it is simultaneously the harmless-seeming product of respiration and combustion that students first encounter in balanced equations, and the central molecule of one of the most consequential scientific and policy debates of the modern era. Understanding its simple linear structure and acidic-oxide chemistry is inseparable, in a full chemistry education, from understanding its outsized role in climate science, carbon capture engineering, and the global carbon budget.
OrganicEthanol
C₂H₆O · 46.07 g/mol
Ethanol (C₂H₅OH) is a two-carbon alcohol with molar mass 46.07 g/mol, featuring a hydroxyl group on a sp³-hybridized carbon. It is fully miscible with water in all proportions due to hydrogen bonding between ethanol's OH and water molecules — a property exploited in alcoholic beverages, disinfectants, and solvent systems. Ethanol is produced biologically by yeast fermentation: C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂. Industrial bioethanol from corn and sugarcane serves as gasoline additive (E10, E85) and potential renewable fuel. Blood alcohol concentration (BAC) is measured in mg/dL or ‰; ethanol distributes in total body water and is metabolized primarily by alcohol dehydrogenase to acetaldehyde, then aldehyde dehydrogenase to acetate.
BaseAmmonia
NH₃ · 17.03 g/mol
Ammonia (NH₃) is a colorless gas with molar mass 17.03 g/mol (N 14.01 + 3 × 1.008), characterized by a pungent odor detectable below 1 ppm. Its trigonal pyramidal geometry (107° bond angle) and lone pair on nitrogen make it a Brønsted base — it accepts protons to form ammonium ion NH₄⁺ — and a Lewis base that forms coordination complexes with transition metals. The Haber–Bosch process converts N₂ and H₂ to NH₃ at 400–500 °C and 150–300 atm over iron catalyst, consuming roughly 1–2% of global energy production. Fixed nitrogen from ammonia synthesis supports half the world's food supply through fertilizer (urea, ammonium nitrate, ammonium phosphate). NH₃ also serves as a hydrogen carrier in emerging clean-energy schemes because it liquefies at manageable pressure (~10 bar at room temperature) unlike H₂.
What is molar mass?
Understand what molar mass is, how it is calculated, why it matters, and how chemists use it in stoichiometry, laboratory work, and scientific research.
Clear definition
Why chemists rely on it
How to calculate it
Worked example: water
H₂O contains two hydrogen atoms and one oxygen atom. Using atomic masses, (2 × 1.008) + 15.999 = 18.015 g/mol. Oxygen contributes most of the mass even though hydrogen atoms are more numerous.
Read the full calculation guide →Popular chemical compounds
Browse compounds frequently studied in chemistry courses, laboratories, research, and industrial applications.
- Sodium ChlorideNaCl · 58.44 g/mol · Salt
- Sodium HydroxideNaOH · 40.00 g/mol · Base
- WaterH₂O · 18.02 g/mol · Inorganic
- Carbon DioxideCO₂ · 44.01 g/mol · Gas
- EthanolC₂H₆O · 46.07 g/mol · Organic
- AmmoniaNH₃ · 17.03 g/mol · Base
- Calcium CarbonateCaCO₃ · 100.09 g/mol · Salt
- Hydrochloric AcidHCl · 36.46 g/mol · Acid
- Sulfuric AcidH₂SO₄ · 98.07 g/mol · Acid
- Acetic AcidC₂H₄O₂ · 60.05 g/mol · Organic
- Calcium ChlorideCaCl₂ · 110.98 g/mol · Salt
- Sodium CarbonateNa₂CO₃ · 105.99 g/mol · Salt
- Carbon MonoxideCO · 28.01 g/mol · Gas
- Sulfur DioxideSO₂ · 64.06 g/mol · Gas
- Potassium ChlorideKCl · 74.55 g/mol · Salt
- GlucoseC₆H₁₂O₆ · 180.16 g/mol · Organic
- Silver NitrateAgNO₃ · 169.87 g/mol · Salt
- MethaneCH₄ · 16.04 g/mol · Hydrocarbon
- MethanolCH₃OH · 32.04 g/mol · Organic
- ButaneC₄H₁₀ · 58.12 g/mol · Hydrocarbon
- AcetoneC₃H₆O · 58.08 g/mol · Organic
- BenzeneC₆H₆ · 78.11 g/mol · Hydrocarbon
- SucroseC₁₂H₂₂O₁₁ · 342.30 g/mol · Organic
- PropaneC₃H₈ · 44.10 g/mol · Hydrocarbon
- Calcium HydroxideCa(OH)₂ · 74.09 g/mol · Base
- Nitric OxideNO · 30.01 g/mol · Gas
- Potassium NitrateKNO₃ · 101.10 g/mol · Salt
- Ammonium ChlorideNH₄Cl · 53.49 g/mol · Salt
- Sodium BicarbonateNaHCO₃ · 84.01 g/mol · Salt
- Potassium Hydrogen PhthalateKHC₈H₄O₄ · 204.22 g/mol · Organic
- Potassium ChlorateKClO₃ · 122.55 g/mol · Salt
- OctaneC₈H₁₈ · 114.23 g/mol · Hydrocarbon
- Hydrofluoric AcidHF · 20.01 g/mol · Acid
- Sodium SulfateNa₂SO₄ · 142.04 g/mol · Salt
- Potassium BromideKBr · 119.00 g/mol · Salt
- Copper(II) SulfateCuSO₄ · 159.60 g/mol · Salt
- Citric AcidC₆H₈O₇ · 192.12 g/mol · Organic
- Calcium PhosphateCa₃(PO₄)₂ · 310.17 g/mol · Salt
- Magnesium ChlorideMgCl₂ · 95.21 g/mol · Salt
- Salicylic AcidC₇H₆O₃ · 138.12 g/mol · Organic
- Potassium IodideKI · 166.00 g/mol · Salt
- Potassium HydroxideKOH · 56.11 g/mol · Base
- AspirinC₉H₈O₄ · 180.16 g/mol · Organic
- Ethylene GlycolC₂H₆O₂ · 62.07 g/mol · Organic
- Aluminum SulfateAl₂(SO₄)₃ · 342.13 g/mol · Salt
- HexaneC₆H₁₄ · 86.18 g/mol · Hydrocarbon
- Sodium PhosphateNa₃PO₄ · 163.94 g/mol · Salt
- UreaCH₄N₂O · 60.06 g/mol · Organic
- Phosphoric AcidH₃PO₄ · 97.99 g/mol · Acid
- Magnesium OxideMgO · 40.30 g/mol · Oxide
Periodic table of atomic masses
Use standard atomic masses as you calculate molar mass, check homework, and prepare laboratory samples.
Common calculation mistakes
Avoid the errors that most often reduce accuracy on exams and in the laboratory.
- Forgetting that parentheses multiply every atom inside the group.
- Rounding atomic masses too early and drifting from the accepted answer.
- Reporting a number without the unit g/mol.
- Confusing an element’s mass percent with the compound’s total molar mass.
Chemistry learning center
Guides on the mole concept, stoichiometry, percent composition, solution calculations, and more.
What Is Molar Mass?
Molar mass connects the microscopic world of atoms to the grams you weigh in the lab. A full walkthrough of the definition, the history behind it, worked examples with real compounds, and the mistakes that trip up almost every beginner.
How to Calculate Molar Mass
A reliable, repeatable method for any chemical formula — from simple diatomic gases to parentheses, polyatomic ions, and hydrates — with fully worked examples using real compounds.
Stoichiometry Basics
Stoichiometry is the arithmetic of chemical reactions — a complete guide to converting between grams, moles, and particles using balanced equations, with worked examples, lab context, and the mistakes that most often derail beginners.
Common Molar Mass Mistakes
A complete diagnostic guide to the errors that cost students the most points on molar mass problems — why each mistake happens, how to catch it, and how to fix your habits so it never happens again.
The Mole Concept
The mole is chemistry's counting unit — a full exploration of Avogadro's number, why chemists count by weighing, and how the mole links microscopic particles to grams on the balance, with worked examples, lab context, and common pitfalls.
Percent Composition by Mass
Mass percent reveals which elements dominate a compound's mass — a complete guide covering the formula, real worked examples, fertilizer and combustion-analysis context, and the reverse process of finding empirical formulas from percentages.
Empirical and Molecular Formulas
A complete guide to how the simplest whole-number ratio of atoms relates to a molecule's true formula, with combustion-analysis worked examples, lab and pharmaceutical context, and the exact role molar mass plays in closing the gap between them.
Atomic Mass and Relative Atomic Mass
Understand what the numbers on the periodic table mean, how isotopes affect them, why molar mass calculations depend on consistent values, and how mass spectrometry actually measures these numbers in a real lab.
Educational articles
Longer reading on laboratory practice, industrial chemistry, and composition analysis.
- Laboratory Skills
Why Molar Mass Matters in the Lab
From solution preparation to titration stoichiometry, molar mass is what lets chemists convert between grams weighed on a balance and moles used in a reaction.
- Reference Skills
Reading the Periodic Table for Mass
Atomic masses on the periodic table are weighted averages of isotopes — here’s how to use them confidently in calculations.
- Composition Analysis
From Formula to Mass Percent Composition
Mass percent composition reveals which elements dominate a compound’s mass — essential for empirical formula problems.
- Industrial Chemistry
Chlor-Alkali Process: NaOH, NaCl, and Cl₂
Electrolysis of brine ties together molar masses of sodium chloride, sodium hydroxide, and chlorine — core stoichiometry for a multi-billion-dollar industry.
- Industrial Chemistry
Contact Process and Sulfuric Acid H₂SO₄
From sulfur dioxide to sulfur trioxide to sulfuric acid — molar mass tracks every step of the world's most produced chemical.
- Biochemistry
Fermentation, Glucose, and Ethanol
Yeast converts glucose to ethanol and carbon dioxide — a biological stoichiometry problem linking C₆H₁₂O₆, C₂H₆O, and CO₂.
Browse by chemical category
Find acids, bases, salts, oxides, organic compounds, gases, and hydrocarbons with full educational profiles.
Frequently asked questions
Short answers about molar mass, formulas, units, and how to use this library.
Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). For a compound, add the atomic masses of every atom in the chemical formula.