Empirical and molecular formulas
Grade 10 Science Worksheet
Circle the best answer, or write your answer on the line.
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?
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?
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
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
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
Which of these formulas can be simplified, Noah?
- C₁₂H₂₂O₁₁, table sugar
- C₆H₁₂O₆, glucose
- H₂O, water
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
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
Glucose's empirical formula is CH₂O, and n = 6. What is its molecular formula, Tala?
- CH₂O₆
- C₆H₁₂O₆
- C₆H₂O
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