Which of the following statements is false ?
a) S is negative when water condenses at 100oC
b) Ssurroundings is positive when water condenses at 100oC
c) Suniverse is equal to zero when water condenses at 990C
d) Suniverse increases when water condenses at 110oC
To determine which statement is false, we need to understand the concept of entropy change (∆S) during the process of water condensation at different temperatures.
a) Statement a) says that ∆S is negative when water condenses at 100°C. In the process of condensation at a fixed temperature, the ∆S value is typically negative because the liquid state has lower entropy than the corresponding gas state. Thus, statement a) is true.
b) Statement b) says that ∆S surroundings is positive when water condenses at 100°C. The ∆S surroundings depends on the temperature of the surroundings. In the case of water condensation, the surroundings typically gain heat when vapor condenses into liquid, resulting in an increase in ∆S surroundings. Therefore, statement b) is also true.
c) Statement c) claims that ∆S universe is equal to zero when water condenses at 99°C. The entropy change of the universe (∆S universe) is the sum of the entropy change of the system (∆S system) and the entropy change of the surroundings (∆S surroundings). Since both the system and the surroundings experience a change in entropy during condensation, it is unlikely that ∆S universe would be zero. Thus, statement c) is false.
d) Statement d) suggests that ∆S universe increases when water condenses at 110°C. As mentioned before, when water condenses, both the system and surroundings experience an increase in entropy (∆S). Therefore, ∆S universe would indeed increase during the condensation process. Hence, statement d) is true.
In summary, the false statement is c) ∆Suniverse is equal to zero when water condenses at 99°C.