1. What is Molarity?

Molarity (M) is a measure of concentration in chemistry, defined as the number of moles of solute per liter of solution. It's one of the most commonly used units for quantifying the concentration of a solution in chemical and biological laboratories.

2. How to Calculate Molarity from Grams

The formula to calculate molarity from grams is:

Where:

• \( M \) — Molarity (mol/L)
• \( grams \) — Mass of solute in grams
• \( MW \) — Molecular weight of solute (g/mol)
• \( V \) — Volume of solution in liters

Explanation: First convert grams to moles by dividing by molecular weight, then divide by volume in liters to get concentration.

3. Importance of Molarity Calculation

Details: Accurate molarity calculations are essential for preparing solutions with precise concentrations, which is crucial for experiments, chemical reactions, and medical applications.

4. Using the Calculator

Tips: Enter the mass in grams, molecular weight in g/mol, and volume in liters. All values must be positive numbers. For best accuracy, use precise measurements.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molarity and molality?
A: Molarity is moles per liter of solution, while molality is moles per kilogram of solvent. Molarity changes with temperature, molality doesn't.

Q2: How do I find the molecular weight of a compound?
A: Sum the atomic weights of all atoms in the molecule. For example, H₂O is (2×1.008) + 15.999 = 18.015 g/mol.

Q3: Can I use milliliters instead of liters?
A: Yes, but you'll need to convert to liters first (divide mL by 1000) since molarity is defined per liter.

Q4: Why is my calculated molarity different from expected?
A: Possible reasons include impure chemicals, incorrect molecular weight, measurement errors, or volume changes during mixing.

Q5: How precise should my measurements be?
A: For most applications, 4 significant figures is sufficient. Analytical work may require higher precision.