Calculator Input
Formula Used
Molar mass = sum of each element atom count multiplied by its atomic mass.
For calcium carbonate: CaCO3 = Ca + C + 3O.
CaCO3 molar mass = 40.078 + 12.011 + (3 × 15.999) = 100.086 g/mol.
Percent by mass = element mass contribution ÷ total molar mass × 100.
Moles = pure sample mass ÷ molar mass.
Formula units = moles × 6.02214076 × 10^23.
How to Use This Calculator
- Enter CaCO3 or another valid chemical formula.
- Use the formula unit multiplier for grouped formulas.
- Enter sample mass in grams when you need moles.
- Enter purity percentage for real powders or samples.
- Enter target moles to find required weighed mass.
- Choose significant figures for the displayed answer.
- Press Calculate and review the result above the form.
- Use CSV or PDF export for saving the result.
Example Data Table
| Formula | Sample Mass | Purity | Molar Mass | Moles | Main Use |
|---|---|---|---|---|---|
| CaCO3 | 10 g | 100% | 100.086 g/mol | 0.09991 mol | Classroom stoichiometry |
| CaCO3 | 25 g | 95% | 100.086 g/mol | 0.2373 mol | Limestone estimate |
| CaCO3 | 5 g | 80% | 100.086 g/mol | 0.03997 mol | Impure chalk sample |
Calcium Carbonate Molar Mass Guide
Why CaCO3 Matters
Calcium carbonate is a common ionic compound in chemistry labs. It appears in limestone, chalk, marble, shells, antacid tablets, and many classroom reactions. A good molar mass calculation helps convert between grams, moles, formula units, and percent composition. This calculator focuses on CaCO3, but it also accepts other chemical formulas.
Core Calculation
The molar mass of calcium carbonate comes from three atomic mass parts. One calcium atom contributes about 40.078 grams per mole. One carbon atom contributes about 12.011 grams per mole. Three oxygen atoms contribute about 47.997 grams per mole. Added together, the standard result is about 100.086 grams per mole. Small differences may appear when a course uses rounded atomic masses.
Advanced Options
This tool adds more than a simple answer. It breaks the formula into elements. It shows atom counts, mass contributions, and percent composition. It also estimates moles from sample mass and purity. If you enter target moles, it returns the required weighed mass. These options are useful for titration work, stoichiometry, gravimetric analysis, and lab report checking.
Purity Adjustment
Purity matters in real samples. Chalk, limestone, and commercial powders may include moisture or impurities. When purity is below 100 percent, the pure calcium carbonate mass is smaller than the weighed mass. The calculator corrects the mole estimate using the purity percentage. This helps prevent overestimating the available reacting amount.
Formula Entry Notes
The formula parser supports subscripts typed as normal numbers. Enter CaCO3 instead of CaCO₃ if needed. Parentheses and hydrate dots can be used for many other formulas. Review the expanded element table before using the result in a final report. A typing error in the formula can change every conversion.
Practical Use
Use the answer as a study and planning aid. Check your teacher’s atomic mass table when exact rounding is required. For most general chemistry problems, a molar mass near 100.09 g/mol is acceptable. The percent composition is also useful. Calcium is about 40.04 percent, carbon is about 12.00 percent, and oxygen is about 47.96 percent by mass.
Saving Results
The export buttons help save work. Download a CSV file for spreadsheet records. Create a PDF when you need a result sheet. Keep the entered formula, sample values, and calculated composition together for easy review.
FAQs
What is the molar mass of CaCO3?
The molar mass of calcium carbonate is about 100.086 g/mol when using Ca = 40.078, C = 12.011, and O = 15.999.
Why is oxygen multiplied by three?
The formula CaCO3 contains three oxygen atoms. Their combined mass contribution is 3 × 15.999, which equals 47.997 g/mol.
Can I use rounded atomic masses?
Yes. Many classes use Ca = 40, C = 12, and O = 16. That gives a rounded molar mass of 100 g/mol.
What does purity percentage do?
Purity reduces the effective calcium carbonate mass. A 10 g sample at 90% purity contains 9 g of actual CaCO3.
Can this calculator handle other formulas?
Yes. The parser supports many element symbols, normal subscripts, parentheses, and hydrate dots. Check the expanded table after calculation.
What are formula units?
Formula units are the counted particles of an ionic compound. They are found by multiplying moles by Avogadro’s number.
Why do answers differ across sources?
Atomic masses may be rounded differently. Isotope data and classroom tables can also vary slightly. Follow your course table when required.
Is CaCO3 the same as calcium carbonate?
Yes. CaCO3 is the chemical formula for calcium carbonate. It contains calcium, carbon, and oxygen in a 1:1:3 ratio.