Strong and weak acids and bases

Answer Key - Grade 10 Science Worksheet - Challenge Me

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

1. 1.

   HCl and acetic acid are both 0.1 M. HCl ionizes completely, so its [H⁺] is 0.1 M; acetic acid's is 0.0013 M. About how many times more H⁺ does HCl have, Ari?

   77 times
2. 2.

   HCl and acetic acid are both 0.001 M. HCl ionizes completely, so its [H⁺] is 0.001 M; acetic acid's is 0.00013 M. About how many times more H⁺ does HCl have, Esme?

   8 times
3. 3.

   Which has the lower pH: 0.10 M HCl or 0.10 M acetic acid, Kira?

   • The 0.10 M acetic acid
   • The 0.10 M HCl
   • Both have the same pH
4. 4.

   Why is [H⁺] in 0.10 M HCl equal to 0.10 M, Luz?

   • Water adds that much H⁺
   • Every HCl molecule splits
   • HCl is a concentrated acid
5. 5.

   Milo says acetic acid is weak because vinegar is mostly water. Agree or disagree?

   • Disagree: weak means partly split
   • Agree: weak just means watered down
   • Agree: water makes any acid weak
6. 6.

   Noah says 6 M acetic acid is a strong acid because it is concentrated. Agree or disagree?

   • Disagree: it is concentrated but weak
   • Agree: more acid means it splits more fully
   • Agree: concentrated means strong
7. 7.

   Pia says a strong acid has a lower pH than a weak acid, whatever their concentrations. Agree or disagree?

   • Agree: weak acids have pH above 7
   • Agree: strong acids win at any amount
   • Disagree: concentration matters too
8. 8.

   Citric acid is a weak acid. Why is lemon juice still about pH 2.2, Ren?

   • Citric acid is a strong acid
   • It holds plenty of citric acid
   • Lemon juice has HCl in it
9. 9.

   Milk of magnesia, Mg(OH)₂, is about pH 10.5, far milder than 1.0 M NaOH at 14.0. Why, Tala?

   • It has no OH⁻ in it
   • Mg(OH)₂ is an acid
   • Little Mg(OH)₂ dissolves
10. 10.

    Which pH fits 0.10 M acetic acid, Zee?

    • About 1.0
    • About 2.9
    • About 7.0