Question

Which of the following has the greater entropy?

(a) 1 mol H₂(g) at STP or 1 mol H₂(g) at 100 °C and 0.50 atm.
(b) 1 mol H₂O(s) at 0 ºC or
(c) 1 mol H₂(g) at STP or 1 mol SO₂(g) at STP
(d) 1 mol N₂O₄(g) at STP or 2 mol NO₂(g) at STP

Answer 1

The substance with either higher temperature, lower pressure, more complex molecular structure, or greater number of particles will generally have higher entropy. Therefore, in the given scenarios, the second option in (a), gases in (b) and (c), and 2 moles of NO2(g) in (d) have higher entropy.

Step-by-step explanation:

To predict which substance in each pair has the higher entropy, we need to consider factors such as temperature, pressure, physical state, and molecular complexity.

• (a) Between 1 mol H₂(g) at STP (Standard Temperature and Pressure) and 1 mol H₂(g) at 100 °C and 0.50 atm, the latter has the greater entropy since entropy increases with temperature and decreases with pressure.
• (b) The comparison is between 1 mol H₂O(s) (solid state) at 0 ºC and the gaseous state of H₂ and SO₂ at STP. The H₂O(s) at 0 ºC has lower entropy compared to gases at STP.
• (c) When comparing gases of similar molar amounts at STP, the gas with more complex molecular structure (SO₂) has higher entropy than a simpler gas (H₂).
• (d) For 1 mol N₂O₄(g) vs. 2 mol NO₂(g) both at STP, the 2 mol NO₂(g) will have higher entropy because entropy is an extensive property, and the number of gas particles is greater.