Compound library
Compounds
Common reference examples with physical data, hazards, uses and beginner explanations.
Water is a polar molecule with hydrogen bonding, which explains many of its unusual properties.
Molar mass18.015 g/mol
Physical stateLiquid
Density0.997 g/mL at 25 C
Melting point0 C
Boiling point100 C at 1 atm
SolubilityMiscible with many polar substances
pHAbout 7 for pure water at 25 C
HazardsLow hazard in ordinary educational contexts.
SourceNIST Chemistry WebBook / PubChem
Verification statusverified
Uses: Solvent, biological systems, heat transfer, cleaning.
Carbon Dioxide
Gas / CO2
CO2
Carbon dioxide is a linear molecule produced by respiration and combustion.
Molar mass44.01 g/mol
Physical stateGas
Density1.98 g/L at 0 C, 1 atm
Melting pointSublimes at -78.5 C at 1 atm
Boiling pointNo normal boiling point at 1 atm; it sublimates instead.
SolubilitySoluble in water; forms carbonic acid equilibrium
pHNot applicable as pure compound
HazardsCan displace oxygen in confined spaces.
SourcePubChem
Verification statusverified
Uses: Carbonated drinks, fire extinguishers, dry ice, atmosphere studies.
Sodium chloride is an ionic compound made of sodium and chloride ions in a crystal lattice.
Molar mass58.44 g/mol
Physical stateSolid
Density2.16 g/cm3
Melting point801 C
Boiling point1465 C
SolubilityAbout 35.9 g/100 mL water at 25 C
pHNear neutral in water
HazardsLow hazard as table salt in ordinary quantities.
SourcePubChem
Verification statusverified
Uses: Food seasoning, preservation, saline solutions, de-icing.
Ethanol
Liquid / C2H6O
C2H6O
Ethanol is an alcohol with a polar hydroxyl group and a small hydrocarbon chain.
Molar mass46.07 g/mol
Physical stateLiquid
Density0.789 g/mL at 20 C
Melting point-114.1 C
Boiling point78.37 C
SolubilityMiscible with water
pHNot applicable as pure compound
HazardsFlammable; avoid ignition sources.
SourcePubChem
Verification statusverified
Uses: Solvent, disinfectant, fuel, chemical feedstock.
Acetic acid is a weak acid; vinegar contains dilute acetic acid.
Molar mass60.05 g/mol
Physical stateLiquid
Density1.049 g/mL at 25 C
Melting point16.6 C
Boiling point117.9 C
SolubilityMiscible with water
pHAcidic in aqueous solution; concentration-dependent
HazardsConcentrated acetic acid is corrosive and flammable.
SourcePubChem
Verification statusverified
Uses: Vinegar component, acetate production, laboratory reagent.
Calcium carbonate is an ionic compound common in shells, limestone and chalk.
Molar mass100.09 g/mol
Physical stateSolid
Density2.71 g/cm3 calcite
Melting pointDecomposes before melting
Boiling pointDecomposes before a normal boiling point is reached.
SolubilityLow solubility in water
pHNot applicable as pure solid
HazardsLow hazard as classroom solid; dust may irritate.
SourcePubChem
Verification statusverified
Uses: Limestone, chalk, antacids, fillers.
Ammonia is a small polar molecule made of nitrogen and hydrogen. In water it behaves as a weak base.
Molar mass17.031 g/mol
Physical stateGas
Density0.73 kg/m3 near room temperature
Melting point-77.7 C
Boiling point-33.3 C
SolubilityHighly soluble in water
pHBasic in aqueous solution; concentration-dependent
HazardsIrritating and toxic gas; avoid inhalation and concentrated solutions.
SourcePubChem
Verification statusverified
Uses: Fertilizer production, cleaning products in dilute form, refrigerant and chemical feedstock.
Methane is the simplest hydrocarbon. Its tetrahedral molecule is nonpolar.
Molar mass16.04 g/mol
Physical stateGas
Density0.657 kg/m3 near room temperature
Melting point-182.5 C
Boiling point-161.5 C
SolubilityLow solubility in water
pHNot applicable as pure gas
HazardsExtremely flammable gas; asphyxiant risk in enclosed spaces.
SourcePubChem
Verification statusverified
Uses: Natural gas fuel, chemical feedstock, atmospheric chemistry studies.
Glucose
Solid / C6H12O6
C6H12O6
Glucose is a simple sugar used by living cells as an energy source.
Molar mass180.156 g/mol
Physical stateSolid
Density1.54 g/cm3
Melting point146 C; decomposes
Boiling pointNot available
SolubilitySoluble in water
pHNot applicable as pure solid
HazardsLow hazard in ordinary educational contexts.
SourcePubChem
Verification statusverified
Uses: Biology energy source, food chemistry, fermentation studies.
Oxygen molecule
Gas / O2
O2
Oxygen gas is a diatomic molecule made from two oxygen atoms.
Molar mass31.998 g/mol
Physical stateGas
Density1.429 g/L at 0 C, 1 atm
Melting point-218.79 C
Boiling point-182.96 C
SolubilitySlightly soluble in water
pHNot applicable as pure gas
HazardsOxidizer; supports combustion.
SourcePubChem
Verification statusverified
Uses: Respiration, medical oxygen, steelmaking and water treatment.
Hydrogen gas is a very light diatomic molecule made of two hydrogen atoms.
Molar mass2.016 g/mol
Physical stateGas
Density0.08988 g/L at 0 C, 1 atm
Melting point-259.16 C
Boiling point-252.88 C
SolubilityLow solubility in water
pHNot applicable as pure gas
HazardsExtremely flammable gas; requires strict ignition control in real laboratories.
SourcePubChem
Verification statusverified
Uses: Fuel cells, hydrogenation, industrial chemical processes and physics demonstrations.