The pH scale and pH calculations

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   A basic solution at 25 °C has [OH⁻] = 0.0001 M. What is its pH, Ari?

   10
2. 2.

   A basic solution at 25 °C has [OH⁻] = 0.001 M. What is its pH, Bo?

   11
3. 3.

   A basic solution at 25 °C has [OH⁻] = 0.01 M. What is its pH, Esme?

   12
4. 4.

   At 25 °C, what do pH and pOH add up to, Kira?

   • 14
   • 7
   • 10
5. 5.

   At 25 °C, a solution has pH 4. What is its pOH, Luz?

   • 4
   • −4
   • 10
6. 6.

   A solution has [H⁺] = 1 × 10⁻⁵ M. What is its pH, Milo?

   • 5
   • 10
   • −5
7. 7.

   A solution has pH 9. What is its [H⁺], Noah?

   • 1 × 10⁻⁹ M
   • 9 M
   • 1 × 10⁹ M
8. 8.

   Vinegar is about pH 2.9 and milk about 6.9. About how many times more H⁺ does vinegar have, Ren?

   • 4 times
   • 10,000 times
   • 40 times
9. 9.

   Ocean surface water is about pH 8.1. How would you describe it, Tala?

   • Slightly basic
   • Slightly acidic
   • Strongly basic
10. 10.

    Ammonia solution is about pH 12.5 and milk of magnesia about 10.5. Which has more OH⁻, Zee?

    • Ammonia solution
    • Milk of magnesia
    • They are equal