What is the standard enthalpy of formation for an element in its standard state?
Practice Questions
Q1
What is the standard enthalpy of formation for an element in its standard state?
0 kJ/mol
100 kJ/mol
298 kJ/mol
1 kJ/mol
Questions & Step-by-Step Solutions
What is the standard enthalpy of formation for an element in its standard state?
Step 1: Understand what 'enthalpy of formation' means. It is 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. It refers to the most stable form of an element at 1 atmosphere of pressure and a specified temperature (usually 25 degrees Celsius).
Step 3: Identify that elements in their standard state are not compounds; they are the pure forms of the elements (like O2 for oxygen, N2 for nitrogen, etc.).
Step 4: Learn that by definition, the standard enthalpy of formation for any element in its standard state is set to 0 kJ/mol. This is a reference point for measuring the enthalpy of formation of compounds.
