Strong and weak acids and bases

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   Acetic acid at 0.1 M has [H⁺] = 0.0013 M. What percent of its molecules have ionized, Ari?

   1.3 %
2. 2.

   Acetic acid at 0.01 M has [H⁺] = 0.00042 M. What percent of its molecules have ionized, Esme?

   4.2 %
3. 3.

   Which phrase describes a dilute acid rather than a weak one, Jun?

   • Little acid per liter of water
   • A pH that is above 7
   • Few molecules split into ions
4. 4.

   Can a solution of a strong acid be dilute, Kira?

   • No: dilute means weak
   • Yes: strength and amount differ
   • No: a strong acid can't be dilute
5. 5.

   Which has more H⁺: 0.10 M HCl or 0.10 M acetic acid, Luz?

   • They are equal
   • The HCl
   • The acetic acid
6. 6.

   Ammonia, NH₃, is a weak base. What does that mean, Milo?

   • It has no hydrogen atoms
   • Each NH₃ takes a proton
   • Few NH₃ molecules take a proton
7. 7.

   What does sodium hydroxide, NaOH, give in water, Noah?

   • H⁺ and NaO⁻ ions
   • Na⁺ and OH⁻, completely
   • Mostly whole NaOH units
8. 8.

   What does a larger Ka tell you about an acid, Ren?

   • It is a weaker acid
   • It is a more dilute acid
   • It is a stronger acid
9. 9.

   Acid A has Ka = 1.8 × 10⁻⁵ and acid B has Ka = 1.8 × 10⁻³. Which is stronger, Tala?

   • Acid A
   • They are equal
   • Acid B
10. 10.

    Acetic acid has Ka = 1.8 × 10⁻⁵. What does the small Ka show, Zee?

    • The vinegar is very dilute
    • Most molecules stay whole
    • It has no hydrogen to give