Answer: 
Explanation:Bond energy of H-H is 436.4 kJ/mole
Bond energy of C-H is 414 kJ/mol
Bond energy of C=C is 620 kJ/mol
Bond energy of C≡C is 835 kJ/mol

= {1B.E(C≡C)+2B.E(C-H) +1B.E(H-H)} - {1B.E(C=C)+4B.E(C-H)}


Explanation:
For the first part,
Reaction equation:
N₂ + 3H₂ → 2NH₃
Given:
Number of moles of NH₃ = 6 moles
Unknown:
Number of moles of N₂ = ?
Solution:
N₂ + 3H₂ → 2NH₃;
From the reaction above, we solve from the known specie to the unknown. Ensure that the equation is balanced;
2 moles of NH₃ is produced from 1 mole of N₂
6 moles of NH₃ will be produced from
mole of N₂
= 3moles of N₂
The number of moles of N₂ is 3 moles
ii.
Given parameters:
Number of moles of sulfur = 2.4moles
Molar mass of sulfur = 32.07g/mol
Unknown:
Mass of sulfur = ?
Solution:
The number of moles of any substance can be found using the expression below;
Number of moles = 
Mass of sulfur = number of moles of sulfur x molar mass
Insert the parameters and solve;
Mass of sulfur = 2.4 x 32.07 = 76.97g
Carbon because they all have CHO in the chemical equations
Only answers C and D would make sense in this question. Hope I helped please give brainiest!
Answer:
The answer to your question is V2 = 333.9 ml
Explanation:
Data
Pressure 1 = P1 = 1.977 atm
Volume 1 = V1 = 517.4 ml
Pressure 2 = P2 = 3.063 atm
Volume 2 = V2 = ?
Process
To solve this problem use Boyle's law
P1V1 = P2V2
-Solve for V2
V2 = P1V1/P2
-Substitution
V2 = (1.977 x 517.4) / 3.063
-Simplification
V2 = 1022.9 / 3.063
-Result
V2 = 333.9 ml