HSC Science (General) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

Calculate the standard enthalpy of combustion of CH_4(g) if Δ_fH°(CH₄) = – 74.8 kJ mol^–1, Δ_fH°(CO₂) = – 393.5 kJ mol^–1 and Δ_fH°(H₂O) = – 285.8 kJ mol^–1.

Define standard enthalpy of formation.

Write the name of biodegradable polymer formed by two amino acids namely glycine and ε-amino caproic acid.

Write the name of raw material used for preparation of nylon 6, 6 polymer.

Calculate the standard enthalpy of formation of liquid methanol from the following data:

1. \[\ce{CH3OH_{(l)} + \frac{3}{2} O_{2(g)} -> CO_{2(g)} + 2H2O_{(l)}}\]     ∆H° = – 726 kJ mol^–1
2. \[\ce{C_{(Graphite)} + O_{2(g)} -> CO_{2(g)}}\]          ∆_cH° = – 393 kJ mol^–1
3. \[\ce{H_{2(g)} + \frac{1}{2} O_{2(g)} -> H2O_{(l)}}\]          ∆_fH° = – 286 kJ mol^–1 

Define the Bond enthalpy.

Calculate the standard enthalpy of the reaction.

\[\ce{2Fe_{(s)} + \frac{3}{2} O_{2(g)} -> Fe2O_{3(s)}}\]

Given:

Define the Enthalpy of ionisation.

Write an application of Hess’s law.

Does the following reaction represent a thermochemical equation?

\[\ce{CH_{4(g)} + 2O_{2(g)} -> CO_{2(g)} + 2H2O_{(g)}}\], ∆_fH° = –900 kJ mol^–1

Classify the following into intensive and extensive properties.

Pressure, volume, mass, temperature.

Write any three advantages of nanoparticles and nanotechnology.

Explain any three characteristic features of nanoparticles.

State disadvantages of nanoparticles and nanotechnology.

Write the name of biodegradable polyamide copolymer.

Derive an expression to calculate molar mass of non-volatile solute by osmotic pressure measurement.

Identify A and B from the following reaction:

\[\begin{array}{cc}
\ce{CH3}\phantom{.................}\\
|\phantom{....................}\\
\phantom{}\ce{2CH3 - C = O ->[Ba(OH)2] A ->[Δ] B + H2O}
\end{array}\]

Write two disadvantages of nanotechnology.

Calculate the standard enthalpy of formation of CH₃OH_(l) from the following data:

1. \[\ce{CH3OH_{(l)} + 3/2 O2_{(g)} -> CO2_{(g)} + 2H2O_{(l)}ΔH^° = - 726 kJ mol^{-1}}\]
2. \[\ce{C_{(s)} + O2_{(g)} → CO2_{(g)}Δ_cH^° = – 393 kJ mol^{-1}}\]
3. \[\ce{H2_{(g)} + 1/2 O2_{(g)} -> H2O_{(l)}Δ_fH^° = - 286 kJ mol^{-1}}\]

Which cells is used as a source of power in flashlights?