The mole: counting particles

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   A sip of water holds 3.011 × 10²³ water molecules. One mole is 6.022 × 10²³ molecules. How many moles is the sip, to 0.01 mol, Ari?

   0.5 mol
2. 2.

   A party balloon holds 9.033 × 10²³ molecules of carbon dioxide (CO₂). One mole is 6.022 × 10²³ molecules. How many moles is that, to 0.01 mol, Bo?

   1.5 mol
3. 3.

   A bowl holds 4.5165 × 10²³ sugar molecules. One mole is 6.022 × 10²³ molecules. How many moles of sugar is that, to 0.01 mol, Kira?

   0.75 mol
4. 4.

   A mole is a counting unit, like a dozen. How many particles are in one mole, to four significant figures, Luz?

   • 12 particles, like a dozen
   • 6.022 × 10²³ grams
   • 6.022 × 10²³ particles
5. 5.

   Which of these is a count of particles, Milo?

   • 2 grams of water
   • 2 liters of water
   • 2 moles of water molecules
6. 6.

   On the mole map, which step turns particles into moles, Noah?

   • Divide by 6.022 × 10²³
   • Divide by the mass of one gram
   • Multiply by 6.022 × 10²³
7. 7.

   On the mole map, which step turns moles into particles, Pia?

   • Add 6.022 × 10²³ to the moles
   • Multiply by 6.022 × 10²³
   • Divide by 6.022 × 10²³
8. 8.

   Which line turns 1.2044 × 10²⁴ molecules into moles, Ren?

   • 1.2044 × 10²⁴ − 6.022 × 10²³ = 6.022 × 10²³ mol
   • (6.022 × 10²³) ÷ (1.2044 × 10²⁴) = 0.5 mol
   • 1.2044 × 10²⁴ ÷ (6.022 × 10²³) = 2 mol
9. 9.

   A dozen eggs and a dozen bricks hold the same count. What is true of 1 mol of water and 1 mol of salt, Tala?

   • They hold the same number of particles
   • They have the same mass, since both are one mole
   • They take up the same space, since both are one mole
10. 10.

    How many eggs are in 2 dozen, and how many molecules are in 2 mol, Esme?

    • 24 eggs; 6.022 × 10²³ molecules
    • 24 eggs; 2 grams of molecules
    • 24 eggs; 1.2044 × 10²⁴ molecules