Question

The thermochemical equation shows the combustion of carbon in oxygen. How many moles of carbon, C must be burnt to produce 196.5 kJ of heat? 

Given thermochemical equation; C(s) + O2(g) -> CO2(g) = -393 kJ mol ‐¹

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Answer 1

0.5 moles OF CARBON WILL BE BURNT SHOULD 196.5 kJ OF HEAT IS LIBERATED IN THE REACTION.

Step-by-step explanation:

The standard heat of combustion of a substance is the heat evolved when one mole of the substance is burned completely in oxygen under standard conditions.

From the reaction, -393kJ of heat is required to burn 1 mole of Carbon completely in oxygen.

C(s) + O2 (g) -----> CO2(g) -393 kJ mol^-1

Should 196.5 kJ of heat was evolved by the reaction, the number of moles of carbon to be produced will be x moles;

-393 kJmol^-1 of heat was required to burn 1 mole of Carbon

196.5 kJ/mol of heat will burn x moles of carbon.

x = ( 196.5 * 1 / -393)

x = -0.5 moles

0.5 moles of carbon will be burnt when 196.5 kJ of heat is liberated