Thermochemistry

Step 1: Convert mass of water into moles.

Step 2: Use standard enthalpy of formation.
Standard enthalpy of formation of water .
Step 3: Calculate energy released.

Step 4: Conclusion.
Hence, the amount of energy liberated is .

Step 1: Understand enthalpy of formation.
Enthalpy of formation is defined as the enthalpy change when one mole of a compound is formed from its elements in their standard states.
Step 2: Analyze the given reaction.
The given reaction shows formation of moles of with enthalpy change .
Step 3: Calculate enthalpy of formation for one mole.

Step 4: Conclusion.
Thus, the enthalpy of formation of is .

Step 1: Recall the structure of lysine.
Lysine is a basic amino acid with an additional amino group in its side chain.
Step 2: Write the general structure.

Step 3: Identify the side chain of lysine.
The side chain consists of four methylene groups followed by an amino group:

Step 4: Conclusion.
The correct side chain present in lysine is option (B).

Step 1: Molar mass of benzene.
The molar mass of benzene (C H ) is calculated as: Step 2: Moles of benzene.
The mass of benzene given is 780 mg = 0.780 g. The number of moles of benzene is: Step 3: Heat liberated.
The heat liberated per mole of benzene is . Therefore, the total heat released for 0.01 mol is: Step 4: Conclusion.
The correct amount of heat liberated is 32.66 kJ, so the correct answer is (A).

Step 1: Write the relation between and .
For reactions involving gases, the relation is:

Step 2: Calculate change in number of moles of gaseous species.
Moles of gaseous reactants (only )
Moles of gaseous products (only )

Step 3: Substitute the value of .

Step 4: Conclusion.
The correct thermodynamic relation for the given reaction is .