C2H2(g) + 2 H2(g)--> C2H6(g)
Bond Bond Energy (kJ/mol)
C-C 347
C=C 611
C-H 414
H-H 436
Calculate the value of the C C (triple bond) energy in C2H2 in kJ/mole.
347
To calculate the value of the C-C (triple bond) energy in C2H2 (acetylene), we will need to use the difference in bond energies between the reactants and products.
The reaction you provided shows the conversion of acetylene (C2H2) and hydrogen gas (H2) into ethane (C2H6). In this reaction, the triple bond in C2H2 is being broken, and two C-H bonds are being formed in each molecule of ethane (C2H6).
Given the bond energies:
C-C (single bond): 347 kJ/mol
C=C (double bond): 611 kJ/mol
C-H: 414 kJ/mol
We can calculate the energy required to break the C-C triple bond by subtracting the bond energy of the reactants (the triple bond) from the bond energy of the products (the two C-H bonds formed).
The reactant side has one C-C (triple bond) and two H-H bonds.
The product side has two C-H bonds.
Bond energy of the reactants:
1 C-C (triple bond) = 347 kJ/mol
2 H-H (bonds) = 2 * 436 kJ/mol = 872 kJ/mol
Bond energy of the products:
2 C-H (bonds) = 2 * 414 kJ/mol = 828 kJ/mol
To calculate the energy change, we subtract the energy of the reactants from the energy of the products:
Energy change = (Energy of bonds formed) - (Energy of bonds broken)
= (2 C-H bonds) - (1 C-C bond + 2 H-H bonds)
= 828 kJ/mol - (347 kJ/mol + 872 kJ/mol)
= 828 kJ/mol - 1219 kJ/mol
= -391 kJ/mol
The negative sign indicates that the reaction is exothermic, meaning energy is released during the reaction.
Therefore, the value of the C-C (triple bond) energy in C2H2 is approximately -391 kJ/mol.
To calculate the energy of the C-C triple bond (C≡C) in C2H2, we need to consider that the triple bond consists of one sigma bond (σ) and two pi bonds (π).
The total bond energy of the C-C triple bond can be calculated as:
Triple Bond Energy (C≡C) = Sigma Bond Energy + 2 × Pi Bond Energy
Given the bond energy values:
C-C (σ) = 347 kJ/mol
C=C (π) = 611 kJ/mol
Therefore:
Triple Bond Energy (C≡C) = 347 kJ/mol + 2 × 611 kJ/mol
= 347 kJ/mol + 1222 kJ/mol
= 1569 kJ/mol
Thus, the value of the C-C (triple bond) energy in C2H2 is 1569 kJ/mol.