Empirical and molecular formulas
Grade 10 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
One mole of glucose is 180.18 g, and 40% of that is carbon (12.01 g/mol). How many C atoms are in one glucose molecule, Esme?
One mole of glucose is 180.18 g, and 53.3% of that is oxygen (16 g/mol). How many O atoms are in one glucose molecule, Jun?
One mole of table sugar is 342.34 g, and 42.1% of that is carbon (12.01 g/mol). How many C atoms are in one sugar molecule, Kira?
Milo says glucose's empirical formula is C₃H₆O₃, since each subscript was halved. Which reply fits, Luz?
- Agree: halving gives the simplest ratio
- Agree: any common factor gives the empirical formula
- Disagree: dividing by 6, the common factor, gives CH₂O
Tala says table sugar, C₁₂H₂₂O₁₁, simplifies to C₆H₁₁O₅.₅. Which reply fits, Milo?
- Disagree: subscripts must stay whole, so it stays C₁₂H₂₂O₁₁
- Agree: halving each subscript simplifies it
- Agree: half-atoms are allowed in an empirical formula
Ari says a molecular formula can match its empirical formula. Which reply fits, Noah?
- Agree: water, H₂O, is both, with n = 1
- Disagree: glucose alone has an empirical formula
- Disagree: a molecular formula must be at least double
A glucose sample has 12.01 g C, 2.02 g H and 16.00 g O. Which empirical formula fits, Pia?
- CH₂O, from 1 mol C : 2 mol H : 1 mol O
- C₁₂H₂O₁₆, reading the grams as the atom counts
- CHO, since each element appears once in the list
A sample of baking soda gives 0.5 mol Na, 0.5 mol H, 0.5 mol C and 1.5 mol O. Which formula fits, Ren?
- Na₂H₂C₂O₆, a simpler-looking ratio
- NaHCO, since each element shows up
- NaHCO₃, from 1 : 1 : 1 : 3
A compound has empirical formula CH₂O and molar mass 180.18 g/mol. What is its molecular formula, Ari?
- C₆H₁₂O₆, since 180.18 ÷ 30.03 = 6
- C₆H₂O, multiplying just the carbon
- CH₂O, since the empirical formula is final
Glucose's molecular formula is 6 × CH₂O. Which formula is that, Bo?
- CH₂O₆
- C₆H₂O
- C₆H₁₂O₆