71.

For the reaction,

$2{\mathrm{H}}_2\left(\mathrm{g}\right) + {\mathrm{O}}_2\left(\mathrm{g}\right) \to 2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right), ∆\mathrm{H}°= - 573.2 \mathrm{kJ}$

The heat of decomposition of water per mole is

• 286.6 kJ

• 573.2 kJ

• -28.66 kJ

• Zero

Hess's law is based on

• law of conservation of mass

• law of conservation of energy

• first law of thermodynamics

• None of the above

Which of the following is a path function?

• Internal energy

• Enthalpy

• Work

• Entropy

If for the cell reaction,

Zn + Cu²⁺ $\rightleftharpoons$ Cu + Zn²⁺;

entropy change $∆\mathrm{S}°$ is 96.5 J mol^-1K^-1, then temperature coefficient of the emf of a cell is

• 5 × 10^-4 VK^-1

• 1 × 10^-3 VK^-1

• 2 × 10^-3 VK^-1

• 9.65 × 10^-4 VK^-1

Cell reaction is spontaneous, when

• ${\mathrm{E}}_{\mathrm{red}}^{°} \mathrm{is} \mathrm{negative}$

• ${\mathrm{E}}_{\mathrm{red}}^{°} \mathrm{is} \mathrm{positive}$

• $∆\mathrm{G}° \mathrm{is} \mathrm{negative}$

• $∆\mathrm{G}° \mathrm{is} \mathrm{positive}$

16 g of oxygen gas expands isothermally and reversibly at 300 K from 10 dm³ to 100 dm³. The work done is (in J)

• zero

• - 2875 J

• + 2875 J

• infinite

$$\begin{gathered} \mathrm{If} \mathrm{C}\left(\mathrm{s}\right) + {\mathrm{O}}_2\left(\mathrm{g}\right) \to \mathrm{CO}\left(\mathrm{g}\right); ∆\mathrm{H} = \mathrm{r} \\ \mathrm{and} \mathrm{CO}\left(\mathrm{g}\right) + \frac{1}{2}{\mathrm{O}}_2\left(\mathrm{g}\right) \to {\mathrm{CO}}_2\left(\mathrm{g}\right); ∆\mathrm{H} =\mathrm{s} \mathrm{then}, \mathrm{the} \mathrm{heat} \mathrm{of} \mathrm{formation} \mathrm{of} \mathrm{CO} \mathrm{is} \end{gathered}$$

• r+s

• r-s

• s-r

• rs

Heat of combustion of methane is -800 kJ. What is the heat of combustion for 4 × 10^-4 kg of methane?

• -800 kJ

• -3.2 × 10⁴ kJ

• -20 kJ

• -1600 kJ

Kirchhoff's equation is

• $\log \frac{{\mathrm{k}}_2}{{\mathrm{k}}_1} = \frac{{\mathrm{E}}_{\mathrm{a}}}{2.303 \mathrm{R}} \left[\frac{1}{{\mathrm{T}}_1} - \frac{1}{{\mathrm{T}}_2}\right]$

• $\log \frac{{\mathrm{p}}_2}{{\mathrm{p}}_1} = \frac{∆{\mathrm{H}}_{\mathrm{v}}}{2.303 \mathrm{R}} \left[\frac{{\mathrm{T}}_2 - {\mathrm{T}}_1}{{\mathrm{T}}_1 \times {\mathrm{T}}_2}\right]$

• $∆{\mathrm{C}}_{\mathrm{p}} = \frac{∆{\mathrm{H}}_2 - ∆{\mathrm{H}}_1}{{\mathrm{T}}_2 - {\mathrm{T}}_1}$

• $\text{log }\frac{{\mathrm{k}}_2}{{\mathrm{k}}_1} = \frac{∆\mathrm{H}}{2.303 \mathrm{R}} \left[\frac{1}{{\mathrm{T}}_1} - \frac{1}{{\mathrm{T}}_2}\right]$

The heat of combustion of carbon is - 393.5 kJ/mol. The heat released upon the formation of 35.2 g of CO₂ from carbon and oxygen gas is

• + 315 kJ

• - 31.5 kJ

• - 315 kJ

• + 31.5 kJ