10th grade Empirical and molecular formulas worksheet

Empirical and molecular formulas

Grade 10 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   A lab analysis of a glucose sample finds 24.02 g of carbon. Carbon is 12.01 g/mol. How many moles of carbon atoms is that, to 0.01 mol, Bo?
2. 2.

   The same analysis finds 32 g of oxygen. Oxygen is 16 g/mol. How many moles of oxygen atoms is that, to 0.01 mol, Jun?
3. 3.

   A glucose sample holds 24.02 g C, 4.04 g H and 32.00 g O, which is 2 mol C, 4 mol H and 2 mol O. What is its empirical formula, Kira?

   • C₂H₄O₂
   • C₂₄H₄O₃₂
   • CH₂O
4. 4.

   A sample holds 24.02 g C, 4.04 g H and 32.00 g O. Why can't you read the formula from the grams, Luz?

   • You can: the formula is C₂₄H₄O₃₂
   • You can, after rounding each mass to a whole number
   • A formula counts atoms, so change grams to moles first
5. 5.

   Moles in a glucose sample: C 2, H 4, O 2. Divide each by the smallest, 2. Which ratio results, Milo?

   • 1 C : 2 H : 1 O
   • 2 C : 4 H : 2 O
   • 1 C : 1 H : 1 O
6. 6.

   Which of these formulas can be simplified, Noah?

   • C₁₂H₂₂O₁₁, table sugar
   • C₆H₁₂O₆, glucose
   • H₂O, water
7. 7.

   Why is CO₂ already its own empirical formula, Pia?

   • It has fewer than three elements
   • 1 and 2 share no common factor but 1
   • Gases have no empirical formulas
8. 8.

   Which mole ratio gives the empirical formula CH₂O, Ren?

   • 2 mol C, 2 mol H, 1 mol O
   • 1 mol C, 1 mol H, 2 mol O
   • 3 mol C, 6 mol H, 3 mol O
9. 9.

   Glucose's empirical formula is CH₂O, and n = 6. What is its molecular formula, Tala?

   • CH₂O₆
   • C₆H₁₂O₆
   • C₆H₂O
10. 10.

    Which shows how to get a molecular formula from an empirical one, Ari?

    • Multiply just the first subscript by n
    • Add n to each subscript
    • Multiply each subscript by n