Question 73: [Physical > Chemical Bonding]
The conversion of graphite into diamond is an endothermic reaction (ΔH = +3 kJ mol–1). C(graphite) → C(diamond)
Which statements are correct? 1 The enthalpy change of atomisation of diamond is smaller than that of graphite. 2 The bond energy of the C–C bonds in graphite is greater than that in diamond. 3 The enthalpy change of combustion of diamond is greater than that of graphite.
Which statements are correct? 1 The enthalpy change of atomisation of diamond is smaller than that of graphite. 2 The bond energy of the C–C bonds in graphite is greater than that in diamond. 3 The enthalpy change of combustion of diamond is greater than that of graphite.
Reference: Past Exam Paper -June 2003 Paper 1 Q33
Solution 73:
Answer: A.
Statement 1 is true because diamond is at a higher level of energy than graphite so it would be easier for it to reach the gaseous state.
If Statement 1 is true then 2 is too because if diamond has a smaller enthalpy change of atomisation then it means the C-C bonds are weaker in diamond than in graphite
Statement 3 is true because the intermolecular forces are higher in graphite so if we were to apply the same heat as to something like diamond, the diamond would break apart easier, and release much more heat, while the same heat applied to graphite will not release as much.
If Statement 1 is true then 2 is too because if diamond has a smaller enthalpy change of atomisation then it means the C-C bonds are weaker in diamond than in graphite
Statement 3 is true because the intermolecular forces are higher in graphite so if we were to apply the same heat as to something like diamond, the diamond would break apart easier, and release much more heat, while the same heat applied to graphite will not release as much.
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