2.4g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atm pressure. The temperature of the calorimeter rises from 298 K to 300 K. The enthalpy change during the combustion of coal is -x kJ mol^-1. The value of x is ____________.

(Given : Heat capacity of bomb calorimeter 20.0 kJ K^-1. Assume coal to be pure carbon)

<p>&nbsp;<math><mrow><mi>C</mi><mrow><mo> (</mo><mrow><mi>s</mi></mrow><mo>)</mo></mrow><mo>+</mo><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo> (</mo><mrow><mi>g</mi></mrow><mo>)</mo></mrow><mo>→</mo><mi>C</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mrow><mo> (</mo><mrow><mi>g</mi></mrow><mo>)</mo></mrow><mtext></mtext><mi>Δ</mi><mi>n</mi><mi>g</mi><mo>=</mo><mn>0</mn></mrow></math></p><p><math><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>C</mi></mrow></msub><mo>=</mo><mn>2</mn><mn>0</mn><mo>×</mo><mn>2</mn><mo>=</mo><mn>4</mn><mn>0</mn><mi>k</mi><mi>J</mi></mrow></math></p><p>Number of moles of C =&nbsp;<math><mrow><mfrac><mrow><mn>2</mn><mo>.</mo><mn>4</mn></mrow><mrow><mn>1</mn><mn>2</mn></mrow></mfrac><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn><mtext> </mtext><mtext> </mtext><mi>m</mi><mi>o</mi><mi>l</mi><mi>e</mi><mi>s</mi></mrow></math></p><p><math><mrow><mi>Δ</mi><msub><mrow><mi>H</mi></mrow><mrow><mi>C</mi></mrow></msub><mo>=</mo><mfrac><mrow><mn>4</mn><mn>0</mn><mi>k</mi><mi>J</mi></mrow><mrow><mn>0</mn><mo>.</mo><mn>2</mn><mi>m</mi><mi>o</mi><mi>l</mi><mi>e</mi></mrow></mfrac><mo>=</mo><mn>2</mn><mn>0</mn><mn>0</mn><mi>k</mi><mi>J</mi><mo>/</mo><mi>m</mi><mi>o</mi><mi>l</mi><mi>e</mi></mrow></math></p>

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