Predict the sign of Delta S in the system for each of the following reactions.
2H3O^+(aq) + CO3^2-(aq) ---> CO2(g) + 3H2O(l)
-,+, or 0?
To predict the sign of ΔS (change in entropy) in the system for the given reaction, we need to consider the number and state of the reactants and products.
In general, when a reactant is converted into a product, the randomness or disorder of the system can either increase or decrease, affecting the sign of ΔS.
1. Let's examine the number and state of the molecules involved:
Reactants:
- 2 moles of H3O+ (aq) (aqueous state)
- 1 mole of CO3^2- (aq) (aqueous state)
Products:
- 1 mole of CO2 (g) (gaseous state)
- 3 moles of H2O (l) (liquid state)
2. Consider the state changes:
- The conversion of H3O+ and CO3^2- ions from the aqueous state to the gaseous and liquid states, respectively, generally increases randomness. Thus, the reaction tends to have a positive ΔS value for these changes.
- The production of CO2 gas from ions also tends to contribute to an increase in randomness, leading to a positive ΔS.
- The formation of H2O in the liquid state does not result in significant changes in randomness, so the ΔS value for this change is expected to be close to zero.
Based on these considerations, we can predict that the overall ΔS for the reaction is likely to be positive (+).