22. Complete and balance the following acid-base equations: (a) A aqueous solution of HClO4 is added to an aqueous solution of LiOH. (b) Aqueous H2SO4 reacts with aqueous NaOH. (c) Ba(OH)2 solid reacts with HF gas.

Answers are in the explanation

Explanation:

An acid-base equation in general is the reaction between an acid and a base that produce water and a salt. Thus:

a) HClO₄(aq) + LiOH(aq) → LiClO₄(aq) + H₂O(l)

   Acid     + Base → Salt      + Water

b) H₂SO₄(aq) + 2NaOH(aq) → Na₂SO₄(aq) + 2H₂O(l)

   Acid     + Base     →   Salt      + Water

c) 2HF(g) + Ba(OH)₂(s) → BaF₂ + 2H₂O

   Acid     + Base → Salt      + Water

I hope it helps!

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.