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How much heat is released when 4.72 g of carbon reacts with oxygen in the equation C +...

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cenicienta | (Level 1) Valedictorian

Posted March 29, 2011 at 8:46 AM via web

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How much heat is released when 4.72 g of carbon reacts with oxygen in the equation C + O2 --> CO2        dH = -393.5 kJ

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted March 29, 2011 at 1:46 PM (Answer #1)

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The reaction of the combustion of carbon is:

C + O2 --> CO2     dH = -393.5 kJ

As dH is negative the reaction is exothermic and burning one mole of carbon releases 393.5 kJ of heat.

The molar mass of carbon is 12. The combustion of 12 g of carbon releases 393.5 kJ of heat, the heat released when one gram of carbon reacts with oxygen is 393.5/12 = 32.79 kJ

When 4.72 g of carbon reacts with oxygen the heat released is (393.5/12)*4.72 = 154.77 kJ.

The required amount of heat released when 4.72 g of carbon reacts with oxygen in the reaction C + O2 --> CO2 is 154.77 kJ.

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