Science & Lab Tools
Graham's Law of Diffusion Calculator
Calculate and compare the rates of diffusion or effusion between different gases based on their molecular masses.
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Related to Graham's Law of Diffusion Calculator
Graham's Law of Diffusion is a fundamental principle in chemistry that describes the relationship between the rate of diffusion or effusion of gases and their molecular masses. The law states that the rate of diffusion or effusion of a gas is inversely proportional to the square root of its molecular mass.
The Mathematical Formula
The mathematical expression of Graham's Law is: r₁/r₂ = √(M₂/M₁) where: - r₁ and r₂ are the rates of diffusion/effusion of gases 1 and 2 - M₁ and M₂ are the molecular masses of gases 1 and 2
This calculator allows you to solve for different variables in Graham's Law equation. You can calculate: - The rate ratio between two gases - The unknown rate of one gas when the other is known - The molecular mass of one gas when both rates are known - The time taken for diffusion when comparing two gases
The results from Graham's Law calculations provide important insights into gas behavior and properties. Here's how to interpret the different calculations:
Rate Ratio (r₁/r₂)
This ratio tells you how much faster or slower one gas diffuses compared to another. A ratio greater than 1 means gas 1 diffuses faster than gas 2, while a ratio less than 1 means gas 2 diffuses faster than gas 1.
Rate Calculations
When calculating an unknown rate, the result shows how quickly the gas will diffuse or effuse relative to the known rate of the other gas. The units will be the same as the input rate units.
Time Calculations
Time calculations show how long it will take for one gas to diffuse compared to another. This is particularly useful in experimental settings where time measurements are easier to obtain than direct rate measurements.
1. What is the difference between diffusion and effusion?
Diffusion is the movement of gas molecules through another gas, while effusion is the movement of gas molecules through a tiny hole in a barrier. Graham's Law applies to both processes, but effusion typically provides more accurate experimental results since there's less molecular interference.
2. Why do lighter gases diffuse faster than heavier ones?
According to kinetic molecular theory, at the same temperature, all gas molecules have the same average kinetic energy. Since kinetic energy is proportional to mass times velocity squared (KE = ½mv²), lighter molecules must travel faster than heavier ones to maintain the same kinetic energy.
3. Does temperature affect Graham's Law calculations?
Temperature does not directly affect the ratio of diffusion rates in Graham's Law as long as both gases are at the same temperature. This is because temperature changes affect both gases equally, canceling out in the ratio.
4. Can Graham's Law be used for liquids?
No, Graham's Law specifically applies to gases. Liquid diffusion is more complex and is better described by Fick's Laws of Diffusion, which take into account factors like concentration gradients and diffusion coefficients.
5. What is the scientific source for this calculator?
This calculator is based on Thomas Graham's original work published in 1829 and 1833, which established the mathematical relationship between gas diffusion rates and molecular masses. The formula has been validated through extensive experimental research and is supported by kinetic molecular theory. The calculations follow the standard form presented in physical chemistry textbooks, particularly P.W. Atkins' "Physical Chemistry" and R.H. Petrucci's "General Chemistry: Principles and Modern Applications." The implementation adheres to IUPAC (International Union of Pure and Applied Chemistry) standards for gas behavior calculations.