Empirical and molecular formulas

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   Glucose, C₆H₁₂O₆, has 6 carbon atoms and 12 hydrogen atoms. How many H atoms are there for each C atom, Ari?

   2 atoms
2. 2.

   Table sugar, C₁₂H₂₂O₁₁, has 11 oxygen atoms and 22 hydrogen atoms. How many H atoms are there for each O atom, Bo?

   2 atoms
3. 3.

   Glucose, C₆H₁₂O₆, has 12 hydrogen atoms and 6 oxygen atoms. How many O atoms are there for each H atom, to 0.01, Kira?

   0.5 atoms
4. 4.

   What is the empirical formula of glucose, C₆H₁₂O₆, Jun?

   • C₆H₁₂O₆
   • C₃H₆O₃
   • CH₂O
5. 5.

   Is H₂O, water's formula, already an empirical formula, Luz?

   • Yes: 2 and 1 share no common factor but 1
   • No: it must be doubled to H₄O₂
   • No: it simplifies to HO
6. 6.

   Glucose's atoms come in the ratio 6 C : 12 H : 6 O. What is the simplest whole-number ratio, Noah?

   • 3 : 6 : 3
   • 6 : 12 : 6
   • 1 : 2 : 1
7. 7.

   What number do you divide 6, 12 and 6 by to get glucose's simplest ratio, Pia?

   • 2, the first common factor you find
   • 12, the largest subscript
   • 6, their greatest common factor
8. 8.

   Table sugar's ratio is 12 C : 22 H : 11 O. What is its simplest whole-number ratio, Ren?

   • 6 : 11 : 5.5
   • 12 : 22 : 11
   • 1 : 2 : 1
9. 9.

   How many atoms of each element are in one unit of baking soda, NaHCO₃, Tala?

   • 3 of each element
   • 1 Na, 1 H, 1 C and 1 O
   • 1 Na, 1 H, 1 C and 3 O
10. 10.

    Which counts are in one CO₂ molecule, Esme?

    • 1 carbon atom and 1 oxygen atom
    • 1 carbon atom and 2 oxygen atoms
    • 2 carbon atoms and 1 oxygen atom