1. Tardigrade
  2. Question
  3. Chemistry
  4. Sulphur (2.56 g ) is burned in a constant volume calorimeter with excess O 2( g ). The temperature increases from 21.25° to 26.72° C. The bomb has a heat capacity of 923 JK -1. Calorimeter contains 815 g of water. Thus, change in internal energy per mole of SO 2 formed for the reaction is S 8( s )+8 O 2( g ) longrightarrow 8 SO 2( g ) (specific heat of water is 4.184 JK -1 g -1 ).

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Q. Sulphur $(2.56 \,g )$ is burned in a constant volume calorimeter with excess $O _{2}( g )$. The temperature increases from $21.25^{\circ}$ to $26.72^{\circ} C$. The bomb has a heat capacity of $923\, JK ^{-1}$. Calorimeter contains $815 \,g$ of water. Thus, change in internal energy per mole of $SO _{2}$ formed for the reaction is
$S _{8}( s )+8 O _{2}( g ) \longrightarrow 8 SO _{2}( g )$
(specific heat of water is $4.184 \,JK ^{-1} \,g ^{-1}$ ).

Thermodynamics

Solution:

Moles of $S_{8}=\frac{2.56}{256}=0.01$

Moles of $SO _{2}$ formed $=0.08$

Rise in temperature $=(273+26.72) K -(273+21.25) K$

$=5.47\, K$

Total change in internal energy

(as system is at constant volume)

$=-\left(923\, JK ^{-1} \times 5.47 \,K +815\, g \times 4.184 \,JK ^{-1} g ^{-1} \times 5.47 \,K \right)$

$=-23701.29 \,J =-23.70129 \,kJ$

Thus, change in internal energy per mole of $SO _{2}$ formed

$=-\frac{23.7012 \,g}{0.08}=-296.3 \,kJ\, mol ^{-1}$