# Worksheet on Spontaneous process

A process that occurs in a system without giving any input of energy from the surrounding is called spontaneous process.  It is also called as irreversible process and in order to reverse the process input of external energy is needed.

This is a process that occurs on it’s own.

Questions:

1. A spontaneous change is one in which the system suffers:

(a)    An increase in internal energy

(b)   A lowering of free energy

(c)    A lowering of entropy

(d)   No energy change

2. Enthalpy of a reaction at $27^0C is 15 mol^{-1}$. The reaction will be feasible if entropy is:

(a) $-50 J mol^{-1} K^{-1}$

(b) $15 J mol^{-1} K^{-1}$

(c)    Greater than $-50 J mol^{-1} K^{-1}$

(d)   Less than $-50 J mol^{-1} K^{-1}$

3. In which of the following the entropy decreases?

(a)   Rusting of iron

(b)   Vapourization of camphor

(c)    Crystallization of sucrose from solution

(d)   Melting of ice

4. In which of the following statements is true? The entropy of the universe:

(a)    Decreases and tends to zero

(b)   Increases and tends towards maximum value

(c)    Decreases and increases with a periodic rate

(d)   Remains constant

5. $\Delta S^0$ will be highest for the reaction:

(a) $CaCO_3(g) \to Ca(s) +CO_2(g)$

(b) $Ca(s) + 1/2 O_2 (s) \to CaO(s)$

(c) $N_2(g) + O_2(g) \to NO(g)$

(d) $C(g) + O_2(g) \to CO_2(g)$

6. For which of the process $\Delta S$ is negative?

(a) $2SO_3 (g) \to 2SO_2(g) + O_2(g)$

(b) $C(diamond) \to C(graphite)$

(c) $H_2(g) \to 2H(g)$

(d) $N_2(g 1 atm) \to N_2 (g 8 atm)$