Bucky Burner

Stage: 5 Challenge Level: Challenge Level:2 Challenge Level:2


This question will require you to engage in many different aspects of quantitative chemistry. Some parts are related to previous parts, but others are not: you will have to use your judgement in each case.


$1$kg of graphite is completely combusted. How much energy is produced?
 
$1$kg of graphite is placed in an oxygen tank and completely combusted, as is $1$kg of carbon-60. Which results in the largest change in the total volume of gas present? 

$1$kg of Buckminsterfullerine (carbon-60) is then burned and the energy produced measured. Will it be more or less than that produced by burning the graphite?

A $1$ carat diamond weighs $200$mg and the density of pure diamond is $3.52$ g cm$^{-3}$. How big is a 1 carat diamond? Estimate the number of C - C bonds contained in such a diamond. How accurate do you think that your estimate is? What monetary value would you place on each C - C bond in a flawless example of such a $1$ carat diamond?

If this diamond were completely combusted, what volume of carbon dioxide at standard pressure would be produced, once it had cooled to room temperature? What volume of oxygen (measured at standard pressure and temperature) would the reaction use up?

 

CHEMICAL DATA


The average bond enthalpy at room temperature of a C - C bond is $+348$ kJ mol$^{-1}$


The reaction C(graphite) + O$_2\longrightarrow$ CO$_2$ has an enthalpy change of $\Delta H=-393.5$ kJ mol$^{-1}$.



Average bond energies, kcal/mol
C-H 98; O-H 110; C-C 80; C-O 78; H-H 103; C-N 6;5 O=O 116 (2 x 58); C=O 187* (2 x 93.5); C=C 145 (2 x 72.5); (* as found in CO2)

(NB 1 kJ/mol is equal to 0.239 kcal/mol. )