Question

Identify the following statements as true or false.1) All spontaneous reactions occur quickly.2) The energy of the universe is constant; the entropy of the universe increases.3) If a process increases the randomness of the particles of a system, the entropy of the system increases.4) All systems become more disordered spontaneously.5) All spontaneous processes release heat.6) Both Δ Ssys and Δ Ssurr must equal zero at equilibrium.

Answer 1

Answer: The true statements are following:

• Energy of the universe is constant; the entropy of the universe increases.

• If a process increases the randomness of the particles of a system, the entropy of the system increases.

• All spontaneous processes release heat.

• Both $\Delta S_{sys}$ and $S_{surr}$ must equal zero at equilibrium.

Explanation:

Spontaneous reactions are defined as the reaction which occur on its own and they do not require any external force to start.

• All spontaneous reactions show a positive value for change in entropy. Each spontaneous reaction requires different amount of time.

Hence, the statement all spontaneous reactions occur quickly, is false.

• Entropy of the Universe always increases and energy always changes from one form to another. Hence, the statement energy of the universe is constant; the entropy of the universe increases, is true.

• As entropy is the degree of randomness. So, with increases the randomness of the particles of a system there will also be increase in randomness.

Therefore, the statement if a process increases the randomness of the particles of a system, the entropy of the system increases, is true.

• Some processes are non-spontaneous in nature. Hence, the statement all systems become more disordered spontaneously, is false.

• Since, randomness between the molecules increases so, heat is eventually released in all spontaneous processes. Therefore, the statement all spontaneous processes release heat, is true.

• For a reversible process, entropy change of the Universe is equal to 0. Therefore,

            $\Delta S_{Universe} = \Delta S_{system} + \Delta S_{surrounding}$

Hence, the statement both $\Delta S_{sys}$ and $S_{surr}$ must equal zero at equilibrium, is true.