Solubility Calculator (Solid/Liquid/Gas)
SolubilityCalc
Engineering Grade Estimation
Configuration
Scientific Disclaimer
Results assume ideal solution behavior. Neglects activity coefficients, pH, and ionic strength. Mixed-solvent effects are qualitative. Educational use only; not for safety-critical design.
Solubility Limit
Thermodynamic Basis
Phase Behavior Visualization
Basic Definitions
Before using the ChemiCalc Solubility Tool, it helps to understand the core chemical concepts. We use standard thermodynamic principles—like Henry’s Law for gases and polynomial fits for solids—to estimate how much of a substance can dissolve.
Solubility
The maximum amount of a substance (solute) that can dissolve in a specific amount of solvent at a set temperature. It’s the limit of what the liquid can hold.
Solute vs. Solvent
The solute is the stuff you are mixing in (like Salt or Oxygen). The solvent is the liquid doing the dissolving (like Water or Ethanol).
Saturation Point
The exact moment the solution is full. If you add even one more grain of salt, it won’t dissolve—it will just sit at the bottom.
Henry’s Law
A rule for gases: The harder you push (pressure), the more gas dissolves. This is why soda stays fizzy as long as the bottle is sealed tight.
How to Use the Calculator
Select the Phase
Choose Gas (like Oxygen) or Solid (like Salt). This tells the calculator which math model to use.
Choose Solute & Solvent
Pick your chemical. You can also switch the solvent from pure water to mixtures (like Ethanol) to see how that changes things.
Set Temperature & Pressure
Move the sliders. You’ll notice gases prefer cold water, while solids usually dissolve better in hot water.
Analyze
The big number is your limit. Use the “Saturation Check” box to type in your own amount and see if it will dissolve or precipitate.
Calculation Examples
1. Oxygenating an Aquarium (Gas)
Henry’s Law“How much Oxygen can water hold at 25°C (room temp)?”
How we calculate it
We start with the Henry’s Law constant for Oxygen, which is about 0.0013. This number represents how many moles of gas dissolve per unit of pressure.
Since we are at standard pressure (1 atm), the math is straightforward:
0.0013 × 1.0 = 0.0013 moles per Liter
To turn that into grams, we multiply by the weight of an Oxygen molecule (32.00):
0.0013 × 32.00 = 0.0416 g/L
2. Making Syrup (High Temp Solid)
Polynomial Fit“Dissolving Sucrose (Sugar) in hot water at 80°C.”
How we calculate it
Sugar follows a curve. We use three numbers (coefficients) to describe this curve: 180 (the base), 0.9 (the slope), and 0.005 (the curve).
At 80°C, we plug the temperature into the equation:
Base: 180
Slope effect: 0.9 × 80 = 72
Curve effect: 0.005 × 80² = 32
Adding them all up: 180 + 72 + 32 = 284 grams per 100mL of water.
3. Carbonating Soda (Cold Gas)
Pressure Effect“CO₂ solubility at 5°C inside a pressurized bottle (3 atm).”
How we calculate it
Gases dissolve better in the cold. At 5°C, the absorption rate constant for CO₂ jumps up to 0.0607.
Since the bottle is pressurized to 3 times the normal atmosphere (3 atm), we multiply the rate by the pressure:
0.0607 × 3.0 = 0.1821 moles per Liter
Then convert to grams (CO₂ weighs 44.01 g/mol):
0.1821 × 44.01 = 8.01 g/L
4. Salting Out (Ethanol Mix)
Solvent Decay“NaCl Solubility in 50% Ethanol mixture at 25°C.”
How we calculate it
First, we calculate the standard water solubility: 35.6 + (0.04 × 25) = 366 g/L.
Then, we apply the decay factor for 50% ethanol ($e^{-2.5} \approx 0.082085$):
366 × 0.082085 = 30.04 g/L
Frequently Asked Questions
1. How accurate is this calculator?
This is an engineering estimation tool using data from NIST Chemistry WebBook and Perry’s Handbook. It assumes ideal solution behavior, meaning it neglects complex interactions like pH, ionic strength, and activity coefficients.
2. Why does gas solubility drop with heat?
Dissolving gas is usually exothermic (releases heat). Adding heat pushes the equilibrium back towards the gas phase (Le Chatelier’s principle).
3. Why does solid solubility increase with heat?
Dissolving solids usually requires energy (endothermic) to break the crystal lattice. Higher temperatures provide this energy.
4. What units does the tool support?
SI (g/L), Common/Imperial (g/100mL), and Molar (mol/L). Toggle these instantly at the bottom of the tool.
5. Can I use this for pH calculations?
No. This tool assumes a neutral pH (pH 7). Extreme pH levels can significantly alter solubility.
6. What is the “Saturation Check”?
It compares your input against the limit to tell you if the solution is unsaturated (clear) or supersaturated (cloudy/precipitating).
7. Why is my chemical not listed?
We include common industrial/academic compounds. Complex organics often lack simple solubility polynomials.
8. Does pressure affect solids?
For practical purposes, no. Pressure primarily affects Gas solubility, which is why the slider is disabled for Solids.
9. What is Henry’s Law?
It states that the weight of a dissolved gas is proportional to its partial pressure. Formula: C = kH · P.
10. How does the mixture logic work?
We use an exponential decay model for salts to estimate solubility in mixed solvents (e.g., water + ethanol). It is a semi-empirical approximation.
11. What is Supersaturation?
An unstable state where a solution holds more solute than theoretically possible. It will eventually crystalize.
12. Why are salt graphs curved?
Solubility is non-linear. We use quadratic equations (A + BT + CT2) to match real-world data curves.
13. Can I use this for medicine?
No. This is for educational/engineering estimates only. Do not use for pharmaceutical compounding.
14. Why is NaCl (Salt) flat?
Sodium Chloride is unique; its solubility barely changes between 0°C and 100°C, unlike sugar or nitrates.
15. How do I read the graph?
X-axis is Temperature (or Pressure), Y-axis is Solubility. Steep lines indicate high sensitivity to conditions.
Disclaimer: This content is intended for educational and estimation purposes only. Please verify all data with standard chemical literature for critical applications. Calculations assume ideal solution behavior.