Question

use the reaction to answer the question.\\(\ce{ch_{4} + 2o_{2} -> co_{2} + 2h_{2}o}\\)\\(\ce{h-c}\\); 412 kj/mol\\(\ce{o=o}\\); 496 kj/mol\\(\ce{c=o}\\); 743 kj/mol\\(\ce{o-h}\\); 463 kj/mol\\(\ce{what is the total energy of the reaction?}\\)\\(\ce{(1 point)}\\)\\(\ce{ -265 kj/mol}\\)\\(\ce{294 kj/mol}\\)\\(\ce{228 kj/mol}\\)\\(\ce{ -698 kj/mol}\\)

Explanation:

Step1: Calculate energy to break bonds (reactants)

In \( \text{CH}_4 \), there are 4 \( \text{H-C} \) bonds. Energy for \( \text{CH}_4 \): \( 4 \times 412 = 1648 \, \text{kJ/mol} \).
In \( 2\text{O}_2 \), there are 2 \( \text{O=O} \) bonds. Energy for \( \text{O}_2 \): \( 2 \times 496 = 992 \, \text{kJ/mol} \).
Total energy to break bonds: \( 1648 + 992 = 2640 \, \text{kJ/mol} \).

Step2: Calculate energy to form bonds (products)

In \( \text{CO}_2 \), there are 2 \( \text{C=O} \) bonds. Energy for \( \text{CO}_2 \): \( 2 \times 743 = 1486 \, \text{kJ/mol} \).
In \( 2\text{H}_2\text{O} \), there are 4 \( \text{O-H} \) bonds (2 per \( \text{H}_2\text{O} \)). Energy for \( \text{H}_2\text{O} \): \( 4 \times 463 = 1852 \, \text{kJ/mol} \).
Total energy to form bonds: \( 1486 + 1852 = 3338 \, \text{kJ/mol} \).

Step3: Calculate reaction energy

Reaction energy = Energy to break bonds - Energy to form bonds
\( 2640 - 3338 = -698 \, \text{kJ/mol} \)? Wait, no—wait, correction: Wait, \( \text{CO}_2 \) has two \( \text{C=O} \) bonds? Wait, no, \( \text{CO}_2 \) is \( \text{O=C=O} \), so two \( \text{C=O} \) (double bonds). Wait, but earlier calculation: Wait, \( \text{CH}_4 \) (4 H-C: 4×412=1648), \( 2\text{O}_2 \) (2×496=992). Total break: 1648+992=2640.

Products: \( \text{CO}_2 \): 2 C=O bonds (2×743=1486). \( 2\text{H}_2\text{O} \): each \( \text{H}_2\text{O} \) has 2 O-H, so 2×2=4 O-H bonds (4×463=1852). Total form: 1486+1852=3338.

Reaction enthalpy \( \Delta H = \) (energy to break bonds) - (energy to form bonds) = 2640 - 3338 = -698 kJ/mol? Wait, but the options have -698? Wait, the options include -698 kJ/mol. Wait, maybe I miscalculated? Wait, no—wait, \( \text{CH}_4 \) has 4 H-C (4×412=1648), \( 2\text{O}_2 \) (2×496=992). Sum: 1648+992=2640.

Products: \( \text{CO}_2 \): 2 C=O (2×743=1486). \( 2\text{H}_2\text{O} \): 4 O-H (4×463=1852). Sum: 1486+1852=3338.

\( \Delta H = 2640 - 3338 = -698 \, \text{kJ/mol} \). So the correct answer is -698 kJ/mol. Wait, but let me check again. Wait, maybe the bond for \( \text{C=O} \) in \( \text{CO}_2 \) is different? Wait, no, the given \( \text{C=O} \) is 743 kJ/mol. So yes, calculation: 4 H-C (4×412=1648), 2 O=O (2×496=992). Total break: 2640.

Form: 2 C=O (2×743=1486), 4 O-H (4×463=1852). Total form: 3338.

\( \Delta H = 2640 - 3338 = -698 \, \text{kJ/mol} \). So the answer is -698 kJ/mol.

Answer:

-698 kJ/mol (the option: -698 kJ/mol)