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Hess's law calculator
Double a step of −286 and reverse a step of −572, and the contributions of −572 and +572 cancel to an overall ΔH of 0.
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Hydrate formula calculator
Work out how many water molecules a hydrate holds: 24.96 g of hydrate that dries to 15.96 g of salt with a molar mass of 159.6 g/mol gives n of 5, written…
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Hydrogen ion from weak acid calculator
Get the real [H+] of a weak acid solution: 0.1 mol/L with a Ka of 0.000018 gives 0.001332670973 mol/L and a pH of 2.87527706155, from the exact quadratic rather…
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Hydroxide concentration from pOH calculator
Convert pOH straight into hydroxide concentration: a pOH of 7 gives 1 × 10⁻⁷ mol/L, the neutral point of pure water at 25 °C, and a pOH of 1 gives a tenth of a…
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Ideal gas law chemistry calculator
Enter any three of pressure, volume, moles and temperature and get the fourth from PV = nRT: 101325 Pa, 0.0224 m³ and 1 mol give 272.979758798406 K with the SI…
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Integrated rate law order checker
Decide the order of a reaction from your time and concentration readings: when ln[A] against time fits a perfect line with an R² of 1 and the plain…
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Internal energy change calculator
Apply the first law in one step: 500 J of heat absorbed while the system does 200 J of expansion work leaves an internal energy change of 300 J, with a note on…
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Ionic strength calculator
Sum up how charged a solution is: 0.1 mol/L of sodium chloride, entered as its two ions with charges +1 and −1, gives an ionic strength of 0.1 mol/L, and you…
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Isotope abundance calculator
Work back from an element's average atomic mass to the share of each of its two isotopes: chlorine at 35.453 u with isotopes of 34.9689 and 36.9659 u is…
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Ka from pH calculator
Turn a measured pH into the acid dissociation constant: a 0.1 mol/L weak acid at pH 3 holds 0.001 mol/L of hydrogen ions, which gives a Ka of 0.00001010101 and…
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Kb from pKb calculator
Turn a pKb from your table into the base dissociation constant: a pKb of 4.75, typical of ammonia, gives a Kb of 0.000017782794 and a weak-base label, with each…
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Kc from degree of dissociation calculator
Turn a degree of dissociation into an equilibrium constant: with α of 0.1 at a starting 0.1 mol/L, Kc is 0.001111111111 mol/L, leaving 0.09 mol/L of A and 0.01…
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Kp from Kc calculator
Switch an equilibrium constant from concentrations to pressures: a Kc of 0.5 at 298.15 K with one extra mole of gas, a Δn of 1, becomes a Kp of 12.2327158495…
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Lattice energy calculator
Estimate how strongly an ionic crystal holds together: sodium chloride, with charges of 1 and 1, a Madelung constant of 1.74756, a Born exponent of 9.1 and ions…
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Product mass from limiting reactant calculator
Find how many grams of product two reactant charges can make: 10 g of oxygen and 5 g of hydrogen forming water give 11.25 g of water, because the oxygen, at…
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Mass fraction calculator
Find what share of a solution's mass is the dissolved substance: 25 g of salt in 100 g of solution is a mass fraction of 0.25, or 25 %, with 75 g of solvent…
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Mass fraction to mole fraction calculator
Turn the mass fractions of a two-part mixture into mole fractions: salt water that is 0.2 sodium chloride at 58.44 g/mol and 0.8 water at 18.015 g/mol by mass…
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Pure mass from purity calculator
Find how much of a weighed sample is the substance you actually want: 25 g of material at 98.5 % purity holds 24.625 g of pure substance and 0.375 g of…
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Mass of element in sample calculator
Find how many grams of an element a compound sample holds: 100 g of sample in which that element makes up a mass fraction of 0.32, or 32 %, contains 32 g of it…
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Mass of product from reactant calculator
Go from grams of reactant to grams of product in one step: 10 g of oxygen at 32 g/mol turning one to one into carbon dioxide at 44 g/mol gives 0.3125 mol and…
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Mass percent calculator
Get the weight-per-weight concentration printed on labels: 25 g of solute in 100 g of solution is 25 % (w/w), and a 5 % saline means 5 g of salt in every 100 g…
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Mass percent to mole fraction calculator
In a 20% sodium chloride solution, salt is only about 7 of every 100 moles. Enter the mass percent and the two molar masses to get both mole fractions, ready…
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Mass to gas volume stoichiometry calculator
10 g of a reactant at 32 g/mol with a one-to-one mole ratio release 0.3125 mol of gas, which fills 0.007645438655 m³ at 101325 Pa and 298.15 K.
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Mixing three solutions calculator
100 mL at 2 M, 200 mL at 0.5 M and 50 mL at 1 M combine into 350 mL at exactly 1 M. Enter three concentrations and volumes of one solute and see how much each…
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Mixing two solutions calculator
100 mL of a 2 M solution poured into 300 mL at 0.5 M give 400 mL at 0.875 M. Enter the concentration and volume of each solution and get the mixture's strength…
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Molality calculator
Half a mole of solute in 1 kg of water is 0.5 mol/kg, and 2 mol in half a kilogram is 4 mol/kg. Get the molality that freezing-point, boiling-point and osmotic…
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Molality calculator
0.5 mol of solute in 1 kg of solvent is 0.5 mol/kg, and every substitution step is written out next to the answer.
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Molality to molarity calculator
A 1 mol/kg salt solution with a density of 1.04 g/mL and a molar mass of 58.44 g/mol is about 0.983 mol/L.
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Molar mass calculator
Water, H2O, weighs 18.015 g/mol: two hydrogens at 1.008 and one oxygen at 15.999. Type any formula, with parentheses or a hydrate dot, and get its molar mass…
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Molar mass from freezing point depression calculator
2.5 g of an unknown in 0.05 kg of water that freezes 0.465 °C lower, with a Kf of 1.86, has a molar mass of 200 g/mol.
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Molar mass from osmotic pressure
1.2 g of solute in 0.25 L showing 0.52 atm at 298.15 K has a molar mass of 225.834754144615 g/mol.
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Molar solubility from Ksp calculator
A 1:1 salt with a Ksp of 1.8 × 10⁻¹⁰ dissolves to 0.000013416408 mol/L. Enter the Ksp and the number of cations and anions per formula unit to get the molar…
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Molar volume at STP calculator
One mole of ideal gas at 0 °C and 1 atm fills 22.414 L, so any amount in moles becomes a volume in litres and cubic metres in one step.
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Molarity to mass percent calculator
A 1 M sodium chloride solution with a density of 1.05 g/mL is 5.565714285714% salt by mass. Add the density and molar mass to turn a volumetric concentration…
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Molarity to normality calculator
0.5 M sulfuric acid used as a diprotic acid is 1 N. Multiply a molarity by the equivalents each mole supplies in your reaction and get the normality that…
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Mole fraction calculator
In a mixture of 2, 3 and 5 moles, the first component's mole fraction is 0.2. Enter the moles of every component, pick one, and get its share along with the…
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Mole fraction to molality calculator
When the solute makes up 0.1 of the moles in water, at 18.015 g/mol, the molality is 6.167699756376 mol/kg.
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Mole fraction to molarity calculator
Turn a solute mole fraction such as 0.1 into molarity, the moles per litre that titrations and stock labels use, from the solution density in g/mL and the two…
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Gas volume ratio calculator
With coefficients 2 and 1 from a balanced equation, 4 litres of the first gas match 2 litres of the second, as long as both are measured at the same temperature…
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Mole to mole conversion calculator
Four moles of hydrogen in 2 H2 + O2 → 2 H2O give four moles of water: the calculator multiplies your reactant moles by the product coefficient over the reactant…
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Molecular formula calculator
Type an empirical formula such as CH2O and a molar mass of 180.156 g/mol, and get C6H12O6 with the multiplier 6.
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Molecular formula from empirical calculator
Enter 180.156 g/mol for the compound and 30.026 g/mol for the empirical formula, and the calculator returns the multiplier 6 that turns CH2O into C6H12O6.
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Moles to grams calculator
18.015 grams of water with a molar mass of 18.015 g/mol is exactly 1 mole, and the same tool works backwards from moles to grams.
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Moles from molarity and volume calculator
2 litres of a 0.5 mol/L solution contain 1 mole of solute: the calculator multiplies molarity by volume in litres and returns the moles, with the formula shown.
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Most probable molecular speed calculator
Enter 32 g/mol for oxygen and 300 K to get the speed at which the largest share of its molecules travel, the peak of the Maxwell–Boltzmann distribution, in…
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Nernst equation calculator
A Daniell cell with a standard potential of 1.1 V, 2 electrons and a reaction quotient of 0.01 reads about 0.05916 V above standard at 25 °C.
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Neutralization moles calculator
0.025 L of acid and 0.03 L of base, both at 0.1 mol/L, neutralize 0.0025 mol and leave 0.0005 mol of base in excess.
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Normality calculator
Half an equivalent of solute in 1 litre of solution is 0.5 N, and 2 equivalents in half a litre are 4 N.
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Normality to molarity calculator
2 N sulfuric acid, with both protons reacting, is 1 M: molarity is normality divided by the equivalents each mole contributes.
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Number of atoms in sample calculator
18.015 grams of water hold 1 mole of molecules and 1.806642228 × 10²⁴ atoms, since each molecule has 3.
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Osmolarity from osmotic pressure calculator
One atmosphere of osmotic pressure at 298.15 K corresponds to about 0.0409 osmol per litre of dissolved particles.
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Osmotic pressure calculator
A 0.1 M glucose solution at 298.15 K has an osmotic pressure of about 2.45 atm, using the default gas constant of 0.08205746 L·atm/(mol·K).
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Osmotic pressure from molarity calculator
A 0.1 mol/L non-electrolyte at 298.15 K exerts about 2.446 atm when you use the litre-atmosphere gas constant; left at its default, the SI constant gives…
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Osmotic pressure difference calculator
0.3 and 0.15 osmol/L at 298.15 K give a pressure difference that pulls water toward the more concentrated side; with the litre-atmosphere constant both…
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Partial pressure at new temperature calculator
Heat a sealed flask from 298 K to 373 K and the oxygen's 0.21 atm partial pressure rises in the same ratio as the absolute temperature; doubling the kelvins…
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Partial pressure from mole fraction calculator
Air treated as 0.21 oxygen by mole at 1 atm gives an oxygen partial pressure of 0.21 atm. Enter the mole fraction and the total pressure in any unit to get each…
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Particles to grams calculator
6.02214076 × 10²³ water molecules at 18.015 g/mol weigh exactly 18.015 g, because that count is one mole.
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Parts per thousand calculator
5 g of solute in a 1000 g solution is 5 ‰: enter the solute mass and the total mass and you also get the mass fraction and the solvent mass, ready for salinity…
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Element percent by mass calculator
32 g of an element in a compound of 98 g/mol is 32.65 % by mass: enter both masses and get the percentage, the mass fraction and the substitution written out…
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Percent dissociation calculator
Starting at 0.1 and keeping 0.02 undissociated at equilibrium means 80 % has dissociated: enter the two concentrations in the same unit and get the percentage…
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