1. Tardigrade
  2. Question
  3. Chemistry
  4. Diborane is a potential rocket fuel which undergoes combustion according to the reaction. B 2 H 6( g )+3 O 2 (g) longrightarrow B 2 O 3( s )+3 H 2 O ( g ) From the following data, calculate the enthalpy change for the combustion of diborane. 2 B ( s )+(3 / 2) O 2( g ) longrightarrow B 2 O 3 (s) Δ H =-1273 kJ mol -1 H 2( g )+(1 / 2) O 2( g ) longrightarrow H 2 O (l) Δ H =-286 kJ mol -1 H 2 O (l) longrightarrow H 2 O ( g ) Δ H =44 kJ mol -1 2 B ( s )+3 H 2( g ) longrightarrow B 2 H 6( g ) Δ H =36 kJ mol -1

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Q. Diborane is a potential rocket fuel which undergoes combustion according to the reaction.
$B _{2} H _{6}( g )+3 O _{2} (g) \longrightarrow B _{2} O _{3}( s )+3 H _{2} O ( g )$
From the following data, calculate the enthalpy change for the combustion of diborane.
$2 B ( s )+(3 / 2) O _{2}( g ) \longrightarrow B _{2} O _{3} (s)$
$\Delta H =-1273\, kJ\, mol ^{-1}$
$H _{2}( g )+(1 / 2) O _{2}( g ) \longrightarrow H _{2} O (l)$
$\Delta H =-286\, kJ\, mol ^{-1}$
$H _{2} O (l) \longrightarrow H _{2} O ( g )$
$\Delta H =44\, kJ\, mol ^{-1}$
$2 B ( s )+3 H _{2}( g ) \longrightarrow B _{2} H _{6}( g )$
$\Delta H =36\, kJ\, mol ^{-1}$

Thermodynamics

Solution:

To get
$B _{2} H _{6}( g )+3 O _{2}( g ) \longrightarrow B _{2} O _{3}( s )+3 H _{2} O ( g )$
(i) +3 (ii) + (iii) $\times 3-$ (iv)
$2 B ( s )+3 / 2 O _{2}( g ) \longrightarrow B _{2} O _{3}( s )$
$\Delta H =-1273\, kJ / mol$
$3 H _{2}( g )+3 / 2 O _{2}( g ) \longrightarrow 2 H _{2} O ( l )$
$\Delta H =3 \times 286\, kJ / mol$
$3 H _{2} O (l) \longrightarrow 3 H _{2} O ( g ) ; \Delta H =3 \times 44$
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