The entropy change can be calculated by using the expression

ΔS =. When water freezes in a glass beaker, choose the correct statement amongst the following:

In an adiabatic process, no transfer of heat takes place between system and surroundings. Choose the correct option for free expansion of an ideal gas under adiabatic condition from the following.

The pressure-volume work for an ideal gas can be calculated by using the expression w = − dV. The work can also be calculated from the PV– plot by using the area under the curve within the specified limits. When an ideal gas is compressed (a) reversibly or (b) irreversibly from volume V_i to V_f. choose the correct option.

On the basis of thermochemical equations (a), (b) and (c), find out which of the algebric relationships given in options (I) to (iv) is correct.

(a) C (graphite) + O₂ (g) → CO₂ (g); Δ_rH = x kJ mol^–1

(b) C (graphite) + O₂ (g) → CO (g);Δ_rH = y kJ mol^–1

c) CO (g) + O₂ (g) → CO₂ (g);Δ_rH = z kJ mol^–1

Consider the reactions given below. On the basis of these reactions find out which of the algebric relations given in options (I) to (iv) is correct?

(a) C (g) + 4 H (g) → CH₄ (g); Δ_rH = x kJ mol^–1

(b) C (graphite, s) + 2H₂ (g) → CH₄ (g); Δ_rH = y kJ mol^–1