Reaction Energy from Bond Energies

Calculate the total energy in all of the bonds for the molecule C₂H₅OH.

• 1582 kJ/mol

• 2886 kJ/mol

• 3234 kJ/mol

• 2821 kJ/mol

Tags

NGSS.HS-PS1-4

For the reaction 2H₂(g) + O₂(g) → 2H₂O(g) the bond enthalpies (in kJ/mol) are

H-H = x, O=O = y, O-H = z

Which calculation will give the value, in kJ/mol, of ΔH for the reaction?

• 2x + y - 2z

• 4z - 2x - y

• 2x + y - 4z

• 2z - 2x - y

Tags

NGSS.HS-PS1-4

Calculate the change in heat for this reaction.

• 580 kJ

• -114 kJ

• 233 kJ

• -453 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Using the table of average bond energies below the image, the ΔH for the reaction in kJ is.....

• + 160 kJ
• -63 kJ
• - 160 kJ
• -217 kJ

Tags

NGSS.HS-PS1-4

Some average bond enthalpies, in kJ/mol, are as follows:
H-H = 436
Cl-Cl = 242
H-Cl = 431
What is the enthalpy change for the decomposition of hydrogen chloride?
2 HCl --> H₂ + Cl₂

• -184 kJ
• + 184 kJ
• - 247 kJ
• + 247 kJ

Tags

NGSS.HS-PS1-4

What happens when chemical bonds are broken?

• Energy is released

• An explosion occurs

• An exothermic process take place

• An endothermic process take place

Tags

NGSS.HS-PS1-4

Calculate the bond energy for the following reaction.

• -443 kj/mole

• -549 kj/mole

• -649 kj/mole

• -349 kj/mole

Tags

NGSS.HS-PS1-4