1. What is a ppm to mmol/L Calculator?

Definition: This calculator converts concentration from parts per million (ppm) to millimoles per liter (mmol/L) using the molecular weight of the substance.

Purpose: It helps chemists, biologists, and medical professionals convert between these common concentration units used in solutions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{mmol/L} \) — Concentration in millimoles per liter
• \( \text{PPM} \) — Concentration in parts per million
• \( \text{MW} \) — Molecular weight of the substance (g/mol)

Explanation: The ppm value is divided by the molecular weight to convert mass concentration to molar concentration.

3. Importance of Unit Conversion

Details: Accurate conversion between ppm and mmol/L is crucial for preparing solutions, interpreting lab results, and comparing concentrations across different substances.

4. Using the Calculator

Tips: Enter the concentration in ppm and the molecular weight of the substance in g/mol. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is ppm exactly?
A: Parts per million (ppm) is a mass concentration unit representing 1 milligram of substance per kilogram of solution (or 1 mg/L in water).

Q2: When would I need mmol/L instead of ppm?
A: mmol/L is preferred when working with chemical reactions where molar ratios are important, or when comparing different substances.

Q3: Where can I find molecular weights?
A: Molecular weights are available in chemical reference tables, safety data sheets (SDS), or can be calculated from the chemical formula.

Q4: Does this work for all substances?
A: Yes, as long as you have the correct molecular weight for the specific substance you're working with.

Q5: How precise is this conversion?
A: The conversion is mathematically exact, but your results depend on the accuracy of your ppm measurement and molecular weight value.