Bond Energies

The amount of energy needed to break a bond and also the amount of energy released when a bond is made is the

• Activation energy

• Bond energy

• chemical energy

• product energy

Tags

NGSS.HS-PS1-4

Bond energy definition

• The amount of energy in a meal

• The amount of energy in a light bulb

• The amount of energy in a chemical bond

Tags

NGSS.HS-PS1-4

If a reaction is exothermic overall, then more energy has been released during bond making than has been required for bond breaking.

If a reaction is endothermic overall, then more energy has been required during bond breaking than has been released during bond making.

• Both answers are True

• Both answers are false

• Only the top answer is true

• Only the bottom answer is true

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

Using bond enthalpy data, calculate the changes in enthalpy for the following reaction.

CH_{4 (g)} + 2 O_{2 (g}) → CO_{2 (g)} + 2 H₂O_(g)

Various bond energies:

C−H    400 𝑘𝐽∙𝑚𝑜𝑙⁻¹

O=O    500 𝑘𝐽∙𝑚𝑜𝑙⁻¹

C=O    800 𝑘𝐽∙𝑚𝑜𝑙⁻¹

O−H    450 𝑘𝐽∙𝑚𝑜𝑙⁻¹

•   -800 𝑘𝐽∙𝑚𝑜𝑙−1

•   +800 𝑘𝐽∙𝑚𝑜𝑙−1

•   -350 𝑘𝐽∙𝑚𝑜𝑙−1

•   -500 𝑘𝐽∙𝑚𝑜𝑙−1

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

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

The combustion of propane is represented by the equation C₃H₈ + 5O₂ ➝ 2CO₂ + 4H₂O. Find the enthalpy of reaction given the following mean bond enthalpies (kJ mol^-1); C-C 348, C-H 412, O=O 465, C=O 743.

• +1701 kJ mol^-1

• -1701 kJ mol^-1

• +1582 kJ mol^-1

• -1582 kJ mol^-1

Tags

NGSS.HS-PS1-4

The hydrogenation of ethene is represented by the equation C₂H₄ + H₂ ➝ C₂H₆. Find the enthalpy change for this reaction given the following mean bond enthalpies (kJ mol^-1) C=C 612, C-H 412, H-H 436, C-C 348.

• -62 kJ mol^-1

• -86.5 kJ mol^-1

• -124 kJ mol^-1

• -248 kJ mol^-1

Tags

NGSS.HS-PS1-4

The conversion of CO into CO₂ is represented by the equation 2CO + O₂ ➝ 2CO₂. Find the enthalpy change for this reaction given the following mean bond enthalpies (kJ mol^-1); C≡O 351, O=O 497, C=O 743

• +331 kJ mol^-1

• -331 kJ mol^-1

• +886.5 kJ mol^-1

• -886.5 kJ mol^-1

Tags

NGSS.HS-PS1-4