Answer: A) 9.25 KJ.
B) - 148.296 KJ.
C) 296 KJ/mol.
Explanation:
For the reaction: S(s) + O2(g) → SO2(g), ΔH = -296 KJ/mol
A) The number of moles in 1.00 g of S is
n = mass/atomic mass = (1.00 g) / (32.00 g/mol) = 0.03125 mole
So, the quantity of heat when 1.00 g of sulfur burned in oxygen = ΔH of the reaction for 1.0 mole x no. of moles = (-296 KJ/mol) x (0.03125 mole) = 9.25 KJ.
B) The quantity of heat released when 0.501 mole of sulfur is burned in air = ΔH of the reaction for 1.0 mole x no. of moles = (-296 KJ/mol) x (0.501 mol) = - 148.296 KJ.
C) The quantity of energy is required to break up 1.0 mole of SO2(g) into its constituent elements = 296 KJ/mol.
It is the same that the amount of energy released when 1.0 mole of S is burned in oxygen.
The process of formation (burning of S) is exothermic.
On the other hand, the reverse operation (breakdown) must be endothermic (and therefore a positive energy change) = 296 KJ/mol.
