Bond Energy Calculations GCSE Practice Questions

Question 1

Q1. Knowledge Recall (2 marks)

Define bond energy and explain where it can be found.

Question 2

Q2. Application (3 marks)

Explain the difference between a strong and a weak bond, using bond energy as an example.

Question 3

Q3. Data Analysis/Calculations (4 marks)

Calculate the bond energy released when 1 mole of hydrogen gas (H2) is formed from two hydrogen atoms. Bond energy of H-H = 436 kJ/mol.

Question 4

Q4. Calculations/Chemical Equations (3 marks)

Propane (C3H8) burns in oxygen according to the equation:

```

C3H8 + 5O2 -> 3CO2 + 4H2O

```

Given the bond energies:

C-H = 413 kJ/mol

C-C = 347 kJ/mol

C=O = 799 kJ/mol

O-O = 498 kJ/mol

O-H = 463 kJ/mol

Calculate the overall energy change for the reaction.

Question 5

Q5. Application (2 marks)

Explain why the activation energy of a reaction is always higher than the bond energy of the bonds broken.

Question 6

Q6. Knowledge Recall (1 mark)

What is the unit of bond energy?

Question 7

Q7. Data Analysis/Calculations (4 marks)

Calculate the percentage change in bond energy when the C-H bond length increases by 0.01 nm. Bond energy of C-H = 413 kJ/mol.

Question 8

Q8. Application (3 marks)

Explain how the bond energy of a molecule can be used to predict its reactivity.

Question 9

Q9. Knowledge Recall (2 marks)

State the relationship between bond order and bond energy.

Question 10

Q10. Calculations/Chemical Equations (3 marks)

Ethanol (C2H5OH) undergoes combustion in the presence of oxygen to form carbon dioxide and water:

```

C2H5OH + 3O2 -> 2CO2 + 3H2O

```