Question

For which case δη should be about equal to δg? a. so3(g) h2o(g) → h2so4(l) b. caco3(s) → cao(s) co2(g) c. 3 o2(g) → 2 o3(g) d. cl(g) o3(g) → clo(g) o2(g)

Answer 1

The balance of moles of gas (δg) is seen in reaction (c) 3 O2(g) → 2 O3(g) where the number of gaseous reactants is equal to the number of gaseous products, maintaining the volume of gas according to Avogadro's law.

Step-by-step explanation:

The student's question is asking about stoichiometry, specifically the case in which the change in moles of the products and reactants (δη) in a chemical reaction should be about equal to the change in moles of the gas (δg). This balance typically occurs in reactions where the number of moles of gaseous reactants is approximately equal to the number of moles of gaseous products, meaning gas volumes before and after the reaction are nearly the same under the same conditions of temperature and pressure, according to Avogadro's law.

Based on the given reactions, the correct choice would be:

(c) 3 O2(g) → 2 O3(g)

This reaction involves only gases and the total number of moles of gas does not change because 3 moles of O2 produce 2 moles of O3. There is no net change in the amount of gas, and hence the volume (δg is approximately zero). For the other reactions, the number of gaseous molecules changes during the reaction leading to a change in gas volumes.