1. What is the Merck Concentration Equation?

The Merck concentration equation calculates the molar concentration of a solution using Beer-Lambert law. It relates the optical density (absorbance) of a solution to its concentration using the molar extinction coefficient.

2. How Does the Calculator Work?

The calculator uses the Merck concentration equation:

Where:

• \( C \) — Concentration (mol/L)
• \( OD \) — Optical density (dimensionless)
• \( \epsilon \) — Molar extinction coefficient (L/mol/cm)

Explanation: The equation is derived from Beer-Lambert law, which states that absorbance is directly proportional to concentration.

3. Importance of Concentration Calculation

Details: Accurate concentration measurement is crucial for preparing solutions, conducting experiments, and analyzing results in chemistry and biochemistry.

4. Using the Calculator

Tips: Enter optical density (measured from spectrophotometer) and the molar extinction coefficient (specific to the substance being measured). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is optical density?
A: Optical density (OD) is a measure of how much light is absorbed by a solution, typically measured by a spectrophotometer.

Q2: Where do I find the molar extinction coefficient?
A: The molar extinction coefficient (ε) is a property of each substance and can be found in chemical reference tables or published literature.

Q3: What are typical units for this calculation?
A: OD is dimensionless, ε is typically in L/mol/cm, and concentration is in mol/L (Molar).

Q4: Are there limitations to this equation?
A: The Beer-Lambert law assumes a linear relationship and is valid only for dilute solutions where absorbance is less than 1.

Q5: How accurate is this calculation?
A: Accuracy depends on the precision of your OD measurement and the accuracy of the ε value for your specific conditions (pH, temperature, etc.).