Answer:
D +405.0kJ mol-¹
Explanation:
Since bond energy is the energy required to break a bond, the energy of dissociation of X₂H₆ = +2775 kJmol⁻¹.
Since there is one X-X bond and six X-H bonds,
Bond energy of one X-X bond + Bond energy of six X-H bonds = energy of dissociation of X₂H₆.
Since bond energy of one X-H bond = 395 kJ mol⁻¹, then
Bond energy of one X-X bond + Bond energy of six X-H bonds = energy of dissociation of X₂H₆
Bond energy of one X-X bond + 6 × one X-H bond = +2775 kJmol⁻¹.
Bond energy of one X-X bond + 6 × 395 kJ mol⁻¹ = +2775 kJmol⁻¹.
Bond energy of one X-X bond + 2370 kJ mol⁻¹ = 2775 kJmol⁻¹
Bond energy of one X-X bond = 2775 kJmol⁻¹ - 2370 kJ mol⁻¹
Bond energy of one X-X bond = +405 kJmol⁻¹
Should be solid , because a liquid has no definite shape and gas has neither just chemical properties
P4O9 is an oxide of phosphorous
so it will named accordingly
There are four phosphorous atoms and nine oxygen atoms
four will be represented as "tetra"
Nine will represented as "non"
so the name of the compound will be
tetraphosphorous nonoxide