Choose the correct answer. A thermodynamic state function is a quantity _______.

1

(a)

used to determine heat changes

(b)

whose value is independent of path

(c)

used to determine pressure volume work

(d)

whose value depends on temperature only.

For the process to occur under adiabatic conditions, the correct condition is:_______.

1

(a)

\(\triangle \)T = 0

(b)

\(\triangle \)P = 0

(c)

q = 0

(d)

w = 0

As per the available data: ______.

1

(a)

CH₄(g) + 2O₂(g) \(\rightarrow \) CO₂(g) + 2H₂O(l); \(\triangle \)_C \(H^{ \ominus }\) = -890.3 KJ mol^-1

(b)

C(s) + O₂(g) \(\rightarrow \)  CO₂(g) \(\triangle \)_C \(H^{ \ominus }\)=-393.5  KJ mol^-1

(c)

H2(g) + 1/2O2(g) \(\rightarrow \) H2O (l); \(\triangle \)_C\(H^{ \ominus }\)= -285.8  KJ mol^-1

Thermodynamics is applicable to ______.

1

(a)

macroscopic system only

(b)

microsopic system only

(c)

homogeneous system only

(d)

heterogeneous system only

An isochoric process takes place at constant ______.

1

(a)

temperature

(b)

pressure

(c)

volume

(d)

concentration

In the equation, \({ N }_{ 2 }(g)+3{ H }_{ 2 }(g)\rightleftharpoons 2N{ H }_{ 3 }(g)\) what would be the sign of work done?

1

(a)

The sign of work done will be positive, i.e. work will be done on the system due to a decrease in volume.

Predict the change in internal energy for an isolated system at constant volume.

1

(a)

For isolated system there is no transfer of energy as heat or work, so according to the first law of thermodynamics,
\(\triangle U=q+W\)
\(\triangle U=0+0=0\)

If the combustion of 1g of graphite produces 20.4kJ of heat, what will be molar enthalpy change? Give the significance of sign also.

1

(a)

Molar enthalpy change for the combustion of graphite, \(\triangle H\) = enthalpy of combustion of 1 g graphite  molar mass
\(\triangle H=-20.7kJg^{ -1 }\times 12gmol^{ -1 } \)
\(=-2.48\times 10^{ 2 }kJmol^{ -1 }\)
Negative sign in the value of \(\triangle H\) indicates that the reaction is exothermic.

How is entropy of a substance related to temperature?

1

(a)

On increasing temperature, entropy of a substance increases.

Define intensive properties.

1

(a)

Properties which depend on the nature of the substance and not on the amount of the substance are called intensive properties.