The mole: counting particles

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Each water molecule (H₂O) has 2 hydrogen atoms. How many moles of hydrogen atoms are in 3 mol of water, Bo?

   6 mol
2. 2.

   Each carbon dioxide molecule (CO₂) has 2 oxygen atoms. How many moles of oxygen atoms are in 1.5 mol of CO₂, Esme?

   3 mol
3. 3.

   How many water molecules are in 2 mol of water, Kira?

   • 1.2044 × 10²³
   • 3.011 × 10²³
   • 1.2044 × 10²⁴
4. 4.

   How many sugar molecules are in 3 mol of sugar, Milo?

   • 1.8066 × 10²³
   • 2.007 × 10²³
   • 1.8066 × 10²⁴
5. 5.

   A spoon of salt and a spoon of sugar each hold 0.1 mol. Which is true, Noah?

   • The heavier spoonful holds more particles
   • They have the same mass, since both are 0.1 mol
   • They hold the same number of particles
6. 6.

   One mole of water is 18.02 g and 1 mol of glucose is 180.18 g. How do their molecule counts compare, Pia?

   • Water has 10 times as many molecules
   • They are equal: 6.022 × 10²³ each
   • Glucose has 10 times as many molecules
7. 7.

   Why can 1 mol of salt (58.44 g) weigh more than 1 mol of water (18.02 g), Ren?

   • Moles of different substances have equal masses, so the scale is wrong
   • Each salt unit is heavier than a water molecule
   • A mole of salt holds more particles than a mole of water
8. 8.

   How many moles of atoms in total are in 1 mol of CO₂, Tala?

   • 2 mol, counting just the O atoms
   • 3 mol: 1 mol C and 2 mol O
   • 1 mol, one for each molecule
9. 9.

   How many moles of oxygen atoms are in 2 mol of baking soda (NaHCO₃), Zee?

   • 3 mol
   • 2 mol
   • 6 mol
10. 10.

    How many moles of hydrogen atoms are in 0.5 mol of glucose (C₆H₁₂O₆), Ari?

    • 12 mol
    • 6 mol
    • 0.5 mol