1. What is Molar Mass?

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). For compounds, it's the sum of the atomic masses of all atoms in the formula.

2. How is Na₂S Molar Mass Calculated?

The molar mass of sodium sulfide (Na₂S) is calculated as:

Where:

• Na — Atomic mass of sodium = 22.98976928 g/mol
• S — Atomic mass of sulfur = 32.065 g/mol

Calculation: (2 × 22.98976928) + 32.065 = 78.04453856 g/mol

3. Importance of Significant Figures

Details: Significant figures reflect the precision of measurement. The calculator allows you to specify how many significant figures you need for your calculation.

4. Using the Calculator

Tips: Simply enter the number of significant figures you need (1-10) and click calculate. The default value is 4 significant figures.

5. Frequently Asked Questions (FAQ)

Q1: What is the exact molar mass of Na₂S?
A: The exact molar mass is 78.04453856 g/mol, using IUPAC atomic weights.

Q2: Why does the calculator show 78.05 g/mol by default?
A: This is the value rounded to 4 significant figures, which is commonly used in general chemistry.

Q3: How should I choose the number of significant figures?
A: Match the precision of your input data or follow the requirements of your experiment/report.

Q4: What are the units for molar mass?
A: Molar mass is always expressed in grams per mole (g/mol).

Q5: Can I use this for other compounds?
A: This calculator is specifically for Na₂S. Different compounds require different calculations.