Why things dissolve: polarity, electrolytes and nonelectrolytes

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   A cup holds 1 mol of dissolved sugar and 1 mol of dissolved salt. How many moles of dissolved particles is that, Bo?

   3 mol
2. 2.

   A cup holds 0.5 mol of dissolved sugar and 0.25 mol of dissolved salt. How many moles of dissolved particles is that, Esme?

   1 mol
3. 3.

   A jug holds 2 mol of dissolved sugar and 0.5 mol of dissolved salt. How many moles of dissolved particles is that, Jun?

   3 mol
4. 4.

   What happens to a salt crystal as it dissolves in water, Kira?

   • It breaks into tiny NaCl pieces that each stay whole in the water
   • It melts into liquid salt
   • Water pulls its Na⁺ and Cl⁻ ions apart and surrounds them
5. 5.

   In salt water, what are the dissolved particles, Luz?

   • Whole NaCl units
   • Tiny drops of melted salt
   • Separate Na⁺ and Cl⁻ ions
6. 6.

   Why can water pull salt apart, Milo?

   • Its heat melts the salt crystal
   • Its charged ends attract the ions
   • It cuts the salt into whole NaCl pieces
7. 7.

   What happens to sugar as it dissolves, Noah?

   • Its molecules split into charged ions, like salt
   • Its molecules spread apart but stay whole
   • It melts into syrup
8. 8.

   1 mol of sugar dissolves in water. How many moles of dissolved particles form, Pia?

   • 1 mol, since sugar stays whole
   • 0 mol, since the sugar melts away
   • 2 mol, since sugar splits like salt
9. 9.

   A tester lights brightly in salt water, dimly in circle water and not at all in sugar water. Which holds the most ions, Tala?

   • The sugar water
   • They hold the same ions
   • The salt water
10. 10.

    Why does circle water light the tester a little, Zee?

    • Dissolved sugar in it forms ions
    • Water molecules themselves split into many ions in the tap
    • It holds a few dissolved ions from minerals