The Henry’s Law Calculator is a practical tool designed to predict the concentration of a dissolved gas in a liquid under a set of specific conditions. This calculator uses Henry’s Law, a fundamental principle in chemistry that establishes a relationship between the concentration of a gas in a liquid and the partial pressure of that gas above the liquid.
Understanding Henry’s Law
Henry’s Law states that at a constant temperature, the amount of dissolved gas in a liquid is directly proportional to the partial pressure of that gas in contact with the liquid. This relationship can be expressed with the formula:
𝐶=𝑘×𝑃C=k×P
Where:
- 𝐶C is the concentration of the gas in the liquid (usually measured in moles per liter or ppm – parts per million).
- 𝑘k is the Henry’s Law constant, which varies depending on the gas and the liquid (common units include moles per liter per atmosphere 𝑚𝑜𝑙/(𝐿⋅𝑎𝑡𝑚)mol/(L⋅atm) or moles per liter per bar 𝑚𝑜𝑙/(𝐿⋅𝑏𝑎𝑟)mol/(L⋅bar)).
- 𝑃P is the partial pressure of the gas above the liquid, usually measured in atmospheres (atm) or bars.
How to Use the Henry’s Law Calculator
Step 1: Enter the Partial Pressure of the Gas
- Input the partial pressure (𝑃P) exerted by the gas above the liquid. This should be entered in units like atmospheres or bars, depending on your specific scenario.
Step 2: Enter the Henry’s Law Constant
- Input the Henry’s Law constant (𝑘k) for the gas-liquid combination you are analyzing. This constant must be in the correct units to match your measurement of partial pressure.
Step 3: Calculate
- Once the values are entered, click the “Calculate” button. The calculator will multiply the partial pressure by the Henry’s Law constant to provide the concentration of the gas in the liquid.
Example Calculation
Suppose you want to calculate the concentration of oxygen dissolved in water at a partial pressure of 0.21 atmospheres. If the Henry’s Law constant for oxygen in water at a given temperature is 769.23769.23 mol/(L·atm), the calculation would be:
𝐶=769.23×0.21C=769.23×0.21 𝐶=161.54 mol/LC=161.54 mol/L
This result tells us that the concentration of oxygen in water under these conditions is 161.54161.54 mol/L.
Relevant Information Table
| Gas | Henry’s Law Constant 𝑘k (mol/(L·atm)) | Typical Partial Pressure 𝑃P (atm) |
|---|---|---|
| Oxygen (O2) | 769.23 | 0.21 |
| Nitrogen (N2) | 1600.00 | 0.78 |
| Carbon Dioxide (CO2) | 29.41 | 0.0004 |
Conclusion: Benefits and Applications of the Henry’s Law Calculator
The Henry’s Law Calculator is not just a theoretical tool; it has practical applications in various fields such as environmental science, engineering, and medical diagnostics. It helps in predicting how gases will behave when they are dissolved in liquids, which is crucial for designing gas scrubbing systems, understanding blood gas analyses in healthcare, and monitoring the solubility of pollutants in natural waters.