The mole: counting particles

Answer Key - Grade 10 Science Worksheet - Challenge Me

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

1. 1.

   A small glass holds 1.8066 × 10²⁴ water molecules. One mole is 6.022 × 10²³. How many moles is that, to 0.01 mol, Esme?

   3 mol
2. 2.

   A big balloon holds 1.2044 × 10²⁴ CO₂ molecules. One mole is 6.022 × 10²³. How many moles is that, to 0.01 mol, Jun?

   2 mol
3. 3.

   A bag of sugar holds 2.4088 × 10²⁴ sugar molecules. One mole is 6.022 × 10²³. How many moles is that, to 0.01 mol, Kira?

   4 mol
4. 4.

   Kira says 1 mol of salt and 1 mol of sugar have the same mass. Which reply fits, Luz?

   • Disagree: same count, but sugar molecules are heavier
   • Agree: a mole of any substance has one fixed mass in grams
   • Agree: a mole is a mass, like a kilogram
5. 5.

   Jun says 6.022 × 10²³ is a large number picked at random. Which reply fits, Milo?

   • Disagree: it was set to match 12 g of carbon-12
   • Agree: scientists picked it at random
   • Agree: it changes each year with new data
6. 6.

   How many hydrogen atoms are in 0.5 mol of water (H₂O), Pia?

   • 3.011 × 10²³
   • 6.022 × 10²³
   • 6.022 × 10²²
7. 7.

   How many oxygen atoms are in 1 mol of CO₂, Ren?

   • 1.2044 × 10²⁴
   • 1.2044 × 10²³
   • 6.022 × 10²³
8. 8.

   How many atoms in total are in 0.5 mol of CO₂, Tala?

   • 9.033 × 10²³
   • 9.033 × 10²²
   • 3.011 × 10²³
9. 9.

   Which holds more molecules: 2 mol of water or 1 mol of glucose, Zee?

   • 1 mol of glucose, since its molecules are heavier
   • They match, since both samples are measured in moles
   • 2 mol of water, since 2 mol is the larger count
10. 10.

    A sample holds 3.011 × 10²³ glucose molecules. How many moles is that, and is it more or less than 1 mol, Bo?

    • 0.5 mol, less than 1 mol
    • 0.5 g, less than 1 g
    • 5 mol, more than 1 mol