Concentration as molarity

Answer Key - Grade 10 Science Worksheet - Challenge Me

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

1. 1.

   How many grams of salt (58.44 g/mol) are in 0.5 L of 0.2 M salt water, to 0.01 g, Esme?

   5.84 g
2. 2.

   How many grams of sugar (342.34 g/mol) are in 0.25 L of 0.1 M sugar water, to 0.01 g, Jun?

   8.56 g
3. 3.

   How many grams of salt (58.44 g/mol) are in 0.2 L of 1.5 M salt water, to 0.01 g, Kira?

   17.53 g
4. 4.

   Ari says a 1 M solution holds 1 g of solute per liter. Which reply fits, Luz?

   • Agree: M stands for grams per liter of solution
   • Disagree: it holds 1 mol per liter of solution
   • Agree, as long as the solute is table salt
5. 5.

   Kira says 1 mol of sugar plus 1 L of water makes exactly 1 M. Which reply fits, Milo?

   • Disagree: the solution is over 1 L, so under 1 M
   • Agree: 1 mol in 1 L of water is exactly 1 M
   • Agree, as long as the water is stirred well
6. 6.

   What is the total molarity of ions in 0.5 M salt water, Pia?

   • 0.25 M, splitting the 0.5 M in two
   • 0.5 M, counting NaCl as one particle
   • 1.0 M: Na⁺ and Cl⁻ at 0.5 M each
7. 7.

   Which has more dissolved particles: 1 L of 0.5 M salt water or 1 L of 0.5 M sugar water, Tala?

   • The salt water: 1.0 mol of ions against 0.5 mol
   • They match, since both solutions are 0.5 M
   • The sugar water, since sugar molecules are bigger
8. 8.

   A label reads 0.15 M NaCl. How many grams of salt are in 1.00 L, Zee?

   • 8.77 g, from 0.15 × 58.44
   • 0.15 g, the number on the label
   • 389.6 g, from 58.44 ÷ 0.15
9. 9.

   A label reads 0.10 M sucrose. How many grams of sugar are in 500 mL, Ari?

   • 17117 g, using 500 L
   • 34.23 g, using 1 L instead of 0.5 L
   • 17.12 g
10. 10.

    Which label shows the most sugar per liter, Bo?

    • 0.20 M sucrose, since its number looks safest
    • 0.50 M sucrose, at 171.17 g per liter
    • 0.30 M sucrose, the middle value of the three