21. Determine the empirical formula of a compound containing 40% carbon,6.7% hydrogen, and 53.3% oxygen by mass.
22. What is the difference between a strong acid and a weak acid?
23. Calculate the solubility product constant (Ksp) for a salt that dissolvesin water according to the equation:
AB2↔A2++2B−\text{AB}_2 \leftrightarrow \text{A}^{2+} + 2\text{B}^-AB2↔A2++2B− with
[A2+]=0.1 M[\text{A}^{2+}] = 0.1 \text{ M}[A2+]=0.1 M and [B−]=0.2 M[\text{B}^-] = 0.2 \text{
M}[B−]=0.2 M.
24. Explain the concept of enthalpy and its importance in chemicalreactions.