The combustion of glucose, C6 H12 O6 (s), produces carbon dioxide, CO2 (g), and water, H2 O(g), according to the equation below. Upper C subscript 6 upper H subscript 12 upper O subscript 6 (s) plus 6 upper O subscript 2 (g) right arrow 6 upper C upper O subscript 2 (g) plus 6 upper H subscript 2 upper O (l). The enthalpy of the reaction is –2,840 kJ. What is the heat of combustion, per mole, of glucose?

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

gas and precipitate r the correct answers