Formula & Formula Mass – Calculation Practice

Instructions: Fill in your Name and Class/Group before attempting the quiz. For each question, calculate the formula mass of the given compound and enter your answer in g/mol. Round to one decimal place unless a whole number is exact. When finished, click Compute Score to see your results. You may also reveal correct answers for any questions you miss, reset the form to try again, print or save your work as a PDF, and download a CSV of your results. A tolerance of ±0.2 g/mol will be accepted for grading.

Student Information
Calculations
1. Calculate the formula mass of NaCl.Enter a numeric value in g/mol.
— Ans: ≈ 58.4–58.5 g/mol
2. Calculate the formula mass of CaCl₂.Enter a numeric value in g/mol.
— Ans: ≈ 111.0 g/mol
3. Calculate the formula mass of H₂O.Enter a numeric value in g/mol.
— Ans: ≈ 18.0 g/mol
4. Calculate the formula mass of CO₂.Enter a numeric value in g/mol.
— Ans: ≈ 44.0 g/mol
5. Calculate the formula mass of Mg(OH)₂.Enter a numeric value in g/mol.
— Ans: ≈ 58.3 g/mol
6. Calculate the formula mass of Al₂O₃.Enter a numeric value in g/mol.
— Ans: ≈ 102.0 g/mol
7. Calculate the formula mass of K₂SO₄.Enter a numeric value in g/mol.
— Ans: ≈ 174.3 g/mol
8. Calculate the formula mass of C₆H₁₂O₆ (glucose).Enter a numeric value in g/mol.
— Ans: ≈ 180.2 g/mol
9. Calculate the formula mass of NH₄NO₃.Enter a numeric value in g/mol.
— Ans: ≈ 80.0 g/mol
10. Calculate the formula mass of Fe₂O₃.Enter a numeric value in g/mol.
— Ans: ≈ 159.7–160.0 g/mol

Atomic masses used (approx.): H 1.008, C 12.01, N 14.01, O 16.00, Na 22.99, Mg 24.31, Al 26.98, Si 28.09, P 30.97, S 32.07, Cl 35.45, K 39.10, Ca 40.08, Fe 55.85.