1. What is Relative Molecular Mass?

Relative molecular mass (also called molecular weight) is the sum of the atomic masses of all the atoms in a molecule. It's expressed in atomic mass units (u) or grams per mole (g/mol) and is dimensionless.

2. How to Calculate Relative Molecular Mass

The formula for calculating relative molecular mass is:

Steps to calculate:

1. Identify all atoms in the molecule
2. Find each atom's atomic mass from the periodic table
3. Multiply each atomic mass by the number of atoms of that element
4. Sum all these values to get the total molecular mass

3. Importance of Molecular Mass

Applications: Molecular mass is crucial for stoichiometric calculations, determining empirical and molecular formulas, preparing solutions with specific molarity, and understanding physical properties of substances.

4. Using the Calculator

Instructions:

• Add each element in your molecule using the "Add Element" button
• Enter the element symbol (e.g., H for hydrogen, O for oxygen)
• Specify how many atoms of that element are in the molecule
• Remove elements if needed using the × button
• Click "Calculate" to get the molecular mass

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between molecular mass and molar mass?
A: They are numerically identical but molecular mass is dimensionless while molar mass has units of g/mol.

Q2: How do I calculate mass for ionic compounds?
A: Use the same method - ionic compounds don't form molecules but we can calculate formula mass the same way.

Q3: What if my element isn't recognized?
A: This calculator includes common elements. For a complete list, consult a periodic table and calculate manually.

Q4: How accurate are these calculations?
A: Calculations use average atomic masses accounting for natural isotope abundance, accurate for most purposes.

Q5: Can I calculate percentage composition with this?
A: Yes - divide each element's total mass by the molecular mass and multiply by 100 to get percentage.