What is the standard enthalpy change of formation for an element in its standard state?
Practice Questions
1 question
Q1
What is the standard enthalpy change of formation for an element in its standard state?
0 kJ/mol
100 kJ/mol
298 kJ/mol
1 kJ/mol
The standard enthalpy change of formation for an element in its standard state is defined as 0 kJ/mol.
Questions & Step-by-step Solutions
1 item
Q
Q: What is the standard enthalpy change of formation for an element in its standard state?
Solution: The standard enthalpy change of formation for an element in its standard state is defined as 0 kJ/mol.
Steps: 4
Step 1: Understand what 'standard enthalpy change of formation' means. It refers to the heat change when one mole of a compound is formed from its elements in their standard states.
Step 2: Recognize what 'standard state' means. The standard state of an element is its most stable form at 1 atmosphere of pressure and a specified temperature (usually 25 degrees Celsius).
Step 3: Identify that elements in their standard state do not require any energy to form themselves. For example, oxygen gas (O2) is in its standard state as a diatomic molecule.
Step 4: Conclude that since no energy is needed to form an element from itself, the standard enthalpy change of formation for an element in its standard state is defined as 0 kJ/mol.
