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

   Noah says 1 M salt water and 1 M sugar water hold the same grams per liter. Which reply fits, Noah?

   • Disagree: same moles, but 58.44 g against 342.34 g
   • Agree: equal molarity means equal grams per liter
   • Agree: both of them hold 1 g per liter
6. 6.

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

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

   What is the molarity of Na⁺ ions in 0.2 M salt water, Ren?

   • 0.1 M, half the salt
   • 0.2 M
   • 0.4 M, counting both ions
8. 8.

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

   • 0.15 g, the number on the label
   • 8.77 g, from 0.15 × 58.44
   • 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
   • 17.12 g
   • 34.23 g, using 1 L instead of 0.5 L
10. 10.

    Which label shows the most sugar per liter, Bo?

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