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🔬 ScienceFree
Percent ionization of acid calculator
A weak acid at 0.1 mol/L with a Ka of 0.000018 is only a little over 1 % ionized: enter the concentration and Ka and the exact equilibrium is solved for you…
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Percent purity calculator
4.85 g of pure substance in a 5 g sample is 97 % pure: enter the two masses in the same unit and get the purity, the purity fraction and each step of the…
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Percent solution prep calculator
100 g of a 10 % solution needs 10 g of solute and 90 g of solvent: enter the target percent by mass and the total you want to make, and get both weigh-outs in…
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Mass percent to molarity calculator
Sodium chloride at just over five and a half percent by mass, with a density of 1.05 g/mL, is 1 mol/L: enter the mass percent, density and molar mass and get…
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Percent yield calculator
Weighing 8.5 g of dried product against a theoretical 10 g gives an 85 % yield: enter both masses and get the yield, the yield fraction and the substitution…
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pH calculator
A hydrogen ion concentration of 1 × 10⁻⁷ mol/L is pH 7, neutral: enter [H+] in moles per litre and get the pH, an acidic, neutral or basic label and each…
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pH from pOH calculator
A pOH of 4 means a pH of 10, a basic solution at 25 °C: enter the pOH and get the pH as 14 minus pOH, with an acidic, neutral or basic label and each…
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pH to pOH calculator
pH 7 at 25 °C means pOH 7 and 1 × 10⁻⁷ mol/L of both hydrogen and hydroxide ions: enter a pH from 0 to 14 and get the pOH and both ion concentrations in moles…
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Weak acid pH calculator
A weak acid at 0.1 mol/L with a Ka of 0.000018 has a pH just under 3: enter the concentration and Ka or pKa and get the exact pH next to the square-root…
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Weak base pH calculator
Solving the weak-base equilibrium for 0.1 mol/L and a Kb of 0.000018 puts the pH a little above 11: enter the concentration and Kb and get the hydroxide…
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pKb from Kb calculator
Ammonia's Kb of about 1.8 × 10⁻⁵ becomes a pKb of about 4.74: enter any positive Kb from a table, a lab fit or another calculator and get its pKb directly…
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pOH calculator
0.001 mol/L of hydroxide is pOH 3 and pH 11, a clearly basic solution: enter [OH−] in moles per litre and get pOH, pH, the matching [H+] and an acidic, neutral…
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pOH calculator
0.1 mol/L of hydroxide ions is pOH 1, while the pure-water level of 1 × 10⁻⁷ mol/L is the neutral pOH 7: type a known [OH−] and get the pOH, an alkalinity label…
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PPB to molarity calculator
1000 ppb of a solute with a molar mass of 58.44 g/mol, in a solution of density 1 g/mL, is 0.000017111567 mol/L.
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PPM calculator
0.002 g of solute in 1000 g of solution is 2 ppm, or 2000 ppb. Enter the solute mass in grams and then either the solution mass or, for a dilute water sample…
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PPM to mg/L calculator
10 ppm in water of density 1 g/mL is 10 mg/L, and a denser liquid gives proportionally more milligrams per litre.
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PPM to molarity calculator
100 ppm of sodium chloride (58.44 g/mol) is 0.001711156742 mol/L under the dilute-water rule that 1 ppm equals 1 mg per litre.
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PPM to PPB converter
1.5 ppm of residual chlorine is 1500 ppb and 1500000 ppt, because each step from million to billion to trillion is a factor of 1000.
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Pseudo-first-order rate constant calculator
A second-order constant of 0.05 M⁻¹ s⁻¹ with a 0.5 M excess gives an observed constant k′ of 0.025 s⁻¹, simply k times the excess concentration.
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Radioactive decay calculator
100 atoms with a decay constant of 0.1 and 5 units of time on the same time base leave 60.6530659713 atoms, so 0.393469340287 of the sample has decayed.
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Raoult's law vapor pressure calculator
Water at 23.8 torr with a solvent mole fraction of 0.85 gives a solution vapor pressure of 20.23 torr, a drop of 3.57 torr caused by the dissolved solute.
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Raoult's law two-component calculator
A liquid with 0.4 of component 1 (pure vapor pressure 92) and 0.6 of component 2 (35) has partial pressures of 36.8 and 21, a total of 57.8 in the same unit.
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Rate constant at new temperature calculator
A rate constant of 0.0001 at 300 K with an activation energy of 50000 J/mol becomes 0.000190908785 at 310 K, almost double after a 10-degree rise.
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Rate from stoichiometry calculator
A product forming at 0.24 mol per litre per second with a coefficient of 2 gives a reaction rate of 0.12, the single rate every species in the balanced equation…
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Rate law calculator
With k at 0.5, A at 0.1 (first order) and B at 0.2 (second order), the reaction runs at a rate of 0.002, with an overall order of 3.
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Reactant mass needed calculator
To make 13.75 g of a product with a molar mass of 44 g/mol from a reactant of 32 g/mol in a 1:1 ratio, weigh out 10 g of reactant.
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Reaction quotient Q calculator
With reactants at 0.5 and 0.3 (coefficients 1 and 3) and a product at 0.2 (coefficient 2), Q is 0.04 divided by 0.0135, or 2.962962962963.
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Reaction rate calculator
A concentration change of 0.5 mol/L over 10 s is an average rate of 0.05 mol/L per second. Enter the change in concentration and the elapsed time to get the…
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Reduced properties calculator
A gas at 50 bar and 400 K, with a critical pressure of 100 bar and a critical temperature of 300 K, has a reduced pressure of 0.5 and a reduced temperature of…
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Relative vapor pressure lowering calculator
Pure water at 23.8 torr and a solution at 20.23 torr give a lowering of 3.57 torr, a relative lowering of 0.15 or 15 %.
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Reverse osmosis net driving pressure
With a feed osmotic pressure of 25 bar and a pump at 55 bar, the net driving pressure is 30 bar, so reverse osmosis can proceed.
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Root-mean-square speed calculator
Oxygen at 32 g/mol and 298.15 K has a root-mean-square speed of 482.081135827716 m/s. Enter the molar mass in g/mol or kg/mol and the temperature in kelvin to…
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Second-order concentration calculator
Starting at 0.5 mol/L with a second-order rate constant of 0.1 L/(mol·s), 0.333333333333 mol/L remain after 10 s, or 0.666666666667 of the start.
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Second-order half-life calculator
A second-order rate constant of 0.5 L/(mol·s) with an initial concentration of 0.1 mol/L gives a half-life of 20 seconds, because the half-life is one over k…
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Serial dilution calculator
A 1 M stock diluted ten-fold over five steps ends at 0.00001 M. Enter the stock, the factor and the steps, and see each tube's concentration beside its…
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First-order shelf-life calculator
With a first-order rate constant of 0.001 per day, ten percent of the active substance is gone after about 105.36 days.
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Solution density from mass percent
A 20 % solution of a solute at 1.84 g/mL in a solvent at 1 g/mL comes out at about 1.1 g/mL. Enter the mass percent and both pure densities to estimate the…
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Solution freezing point calculator
Water with Kf of 1.86 and a 1 mol/kg non-electrolyte freezes at −1.86 °C instead of 0 °C. Enter the solvent's freezing point, molality, Kf and particle factor…
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Standard cell potential calculator
Copper at +0.34 V as cathode and zinc at −0.76 V as anode give a standard cell potential of +1.10 V.
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Stoichiometric air-fuel ratio calculator
Methane, with one carbon and four hydrogen atoms, needs about 17 kg of dry air per kg of fuel to burn completely.
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Mole ratio calculator
Six moles of hydrogen make four moles of ammonia, because N2 + 3 H2 → 2 NH3 sets a ratio of two to three.
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Theoretical yield calculator
With 2.5 moles of limiting reagent and two moles of product per mole consumed, the theoretical yield is 5 moles.
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Titration equivalence point volume calculator
Titrating 25 mL of a 0.1 M sample with 0.1 M titrant reaches equivalence at 25 mL. Enter the analyte concentration and volume and the titrant concentration…
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Titration pH at equivalence calculator
A 0.05 M salt of a weak acid with a Kb of 5.6 × 10⁻¹¹ gives a pH slightly above 8 at the equivalence point.
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Van der Waals molar volume calculator
At 10 bar and 298.15 K, a gas with a of 3.592 and b of 0.04267 needs slightly less room per mole than an ideal gas.
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Van't Hoff factor calculator
Sodium chloride with a degree of dissociation of 0.8 gives a van 't Hoff factor of 1.8, not 2. Enter the ions per formula unit and the degree of dissociation to…
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Vapor phase composition calculator
An ideal liquid that is 0.6 component 1 and 0.4 component 2, with pure vapor pressures of 100 and 50, makes a vapor that is 0.75 component 1.
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Vapor pressure lowering calculator
A solute mole fraction of 0.1 in a solvent with a vapor pressure of 23.8 lowers it by 2.38, leaving 21.42.
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Volume for target molarity calculator
0.5 mol of solute at a target of 0.25 mol/L needs 2 L of solution, which is 2000 mL. Enter the moles you have and the molarity you want to get the final volume…
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Volume percent to molarity calculator
10 % v/v ethanol becomes a molarity with two facts about the pure liquid: its density (0.789 g/mL) and its molar mass (46.07 g/mol).
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Gas volume to moles calculator
22.4 litres of gas at STP is roughly one mole, and 44.8 litres roughly two. Enter the volume in litres and the tool divides it by the molar volume at 0 °C and 1…
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Weight/volume percent calculator
5 g of solute in 100 mL of solution is 5 % w/v, or 0.05 g per mL. Enter the grams and the final volume in millilitres to get the concentration for a pharmacy…
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Weight-volume % to molarity calculator
A 5.85 % w/v sodium chloride solution, with a molar mass of 58.44 g/mol, is about 1 mol/L. Enter the label percentage and the molar mass and get the molarity…
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Precipitation ion product calculator
With a Ksp of 1.8 × 10⁻¹⁰ and both ions at 0.0001 mol/L in a one-to-one salt, Q is 10⁻⁸, so a precipitate forms.
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Analogous color generator
Give a base color and an angle and get its two hue neighbors: #3366cc with 30 degrees returns #33b2cc and #4c33cc, with the same saturation and lightness, a…
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CMYK to RGB converter
Turn a CMYK swatch into everything a screen needs at once: C0 M50 Y100 K0 gives RGB 255, 128, 0 and the hex code #FF8000, ready to paste into a stylesheet.
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Complementary color finder
Find the color opposite yours on the hue wheel in one step: pure red #FF0000 gives cyan #00FFFF, with the same saturation and lightness, returned as hex, RGB…
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Color to grayscale converter
Get the gray that keeps a color's perceived brightness: #3498db becomes #828282, a gray value of 130, because green counts most, red less and blue least.
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Hex to HSL converter
Turn a hex code into values you can adjust by eye: #FF8040 is hue 20.1°, saturation 100% and lightness 62.55%, ready to paste as hsl(20.1 100% 62.55%).
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Hex to color name
Put a name to a hex code: #ff5733 is closest to tomato, whose own code is #ff6347, picked from 148 CSS named colors by distance in RGB space.
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