Thermodynamics

The energy released when 6 moles of octane is burnt in air will be [Given, ΔH_f for CO₂ (g). H₂O(g) and C₈H₁₈ (l), respectively are -490, -240 and +160J/mol]

• -37.4 kJ

• -20 kJ

• -6.2 kJ

• -35.5 kJ

If for a given substance, melting point is T_B and freezing point is T_A then correct variation of entropy by graph between entropy change and temperature is

Which of the following is the increasing order of enthalpy of vaporization?

• NH₃, PH₃, AsH₃

• AsH₃, PH₃ NH₃

• NH₃, AsH₃, PH₃

• PH₃, AsH₃, NH₃

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

• $∆$T = 0

• $∆$p = 0

• q = 0 

• W = 0

$\frac{3}{2}$O₂(g) $\to$O₃(g); K_p for this reaction is 2.47 x 10^-29. At 298 K, ${∆}_{\mathrm{r}}\mathrm{G}°$ for conversion of oxygen to ozone will be

• 100 kJ mol^-1

• 150 kJ mol^-1

• 163 kJ mol^-1

• 2303 kJ mol^-1

Graphite is a

• molecular solid

• covalent solid

• ionic solid

• metallic solid

For the reaction,

H₂O(l) $\rightleftharpoons$ H₂O(g)

at 373 K and 1 atm pressure

• $∆$H = 0

• $∆$E = 0

• $∆$H = T$∆\mathrm{S}$

• $∆$H = $∆$E

According to the first law of thermodynamics which of the following quantities represents the change in a state function?

• q_rev

• q_rev - W_rev

• $\frac{{\mathrm{q}}_{\mathrm{rev}}}{{\mathrm{W}}_{\mathrm{rev}}}$

• q_rev + W_rev

What is the $∆$H of the reaction?

CH₂Cl₂ (g) $\to$C (g) + 2H (g) + 2Cl (g)

The average bond energies of C-Cl bond and C-H bond are 416 kJ and 325 kJ mol^-1 respectively.

• 1482 kJ

• 1482 J

• 1492 kJ

• 1492 J

The heat of formation of CO(g) and CO₂ (g)are $∆$H = -110 and $∆$H = - 393 kJ mol^-1 respectively. What is the heat of reaction ($∆$H) (in kJ mol^-1) for the following reaction?

CO (g) + $\frac{1}{2}{\mathrm{O}}^2$ (g) $\to$ CO₂(g)

• -504

• -142.5

• -283

• 504