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 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
3. 3.

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

   • Agree: a mole is a mass, like a kilogram
   • Disagree: same count, but sugar molecules are heavier
   • Agree: a mole of any substance has one fixed mass in grams
4. 4.

   Esme says 2 mol of water holds twice as many molecules as 1 mol of sugar. Which reply fits, Noah?

   • Agree: 2 mol is twice the count of 1 mol
   • Disagree: a mole of each substance has the same mass, so they match
   • Disagree: sugar's heavier molecules mean more of them
5. 5.

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

   • 6.022 × 10²³
   • 3.011 × 10²³
   • 6.022 × 10²²
6. 6.

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

   • 6.022 × 10²³
   • 1.2044 × 10²³
   • 1.2044 × 10²⁴
7. 7.

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

   • 9.033 × 10²²
   • 3.011 × 10²³
   • 9.033 × 10²³
8. 8.

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

   • They match, since both samples are measured in moles
   • 2 mol of water, since 2 mol is the larger count
   • 1 mol of glucose, since its molecules are heavier
9. 9.

   Which holds more atoms: 1 mol of water or 1 mol of CO₂ (3 atoms in each molecule), Ari?

   • Water, since its molecules are lighter and pack in
   • They match: 3 mol of atoms each
   • CO₂, since its molecules are heavier
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?

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